[td-225] merge develop.

src/connector/jdbc/CMakeLists.txt

@@ -8,10 +8,8 @@ IF (TD_MVN_INSTALLED)
   ADD_CUSTOM_COMMAND(OUTPUT ${JDBC_CMD_NAME}
     POST_BUILD
     COMMAND mvn -Dmaven.test.skip=true install -f ${CMAKE_CURRENT_SOURCE_DIR}/pom.xml
-    COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/target/taos-jdbcdriver-2.0.29.jar ${LIBRARY_OUTPUT_PATH}
+    COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/target/taos-jdbcdriver-2.0.32-dist.jar ${LIBRARY_OUTPUT_PATH}
     COMMAND mvn -Dmaven.test.skip=true clean -f ${CMAKE_CURRENT_SOURCE_DIR}/pom.xml
     COMMENT "build jdbc driver")
   ADD_CUSTOM_TARGET(${JDBC_TARGET_NAME} ALL WORKING_DIRECTORY ${EXECUTABLE_OUTPUT_PATH} DEPENDS ${JDBC_CMD_NAME})
-ENDIF ()
-
-
+ENDIF ()
\ No newline at end of file

src/connector/jdbc/deploy-pom.xml

@@ -5,7 +5,7 @@
 
   <groupId>com.taosdata.jdbc</groupId>
   <artifactId>taos-jdbcdriver</artifactId>
-  <version>2.0.29</version>
+  <version>2.0.32</version>
   <packaging>jar</packaging>
 
   <name>JDBCDriver</name>

src/connector/jdbc/pom.xml

@@ -3,7 +3,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.taosdata.jdbc</groupId>
     <artifactId>taos-jdbcdriver</artifactId>
-    <version>2.0.29</version>
+    <version>2.0.32</version>
     <packaging>jar</packaging>
     <name>JDBCDriver</name>
     <url>https://github.com/taosdata/TDengine/tree/master/src/connector/jdbc</url>
@@ -47,7 +47,7 @@
         <dependency>
             <groupId>org.apache.httpcomponents</groupId>
             <artifactId>httpclient</artifactId>
-            <version>4.5.8</version>
+            <version>4.5.13</version>
         </dependency>
         <dependency>
             <groupId>com.alibaba</groupId>
@@ -113,16 +113,16 @@
                         <include>**/*Test.java</include>
                     </includes>
                     <excludes>
-                        <exclude>**/TSDBJNIConnectorTest.java</exclude>
-                        <exclude>**/UnsignedNumberJniTest.java</exclude>
-                        <exclude>**/DatetimeBefore1970Test.java</exclude>
                         <exclude>**/AppMemoryLeakTest.java</exclude>
                         <exclude>**/AuthenticationTest.java</exclude>
-                        <exclude>**/TaosInfoMonitorTest.java</exclude>
+                        <exclude>**/ConnectMultiTaosdByRestfulWithDifferentTokenTest.java</exclude>
+                        <exclude>**/DatetimeBefore1970Test.java</exclude>
                         <exclude>**/FailOverTest.java</exclude>
                         <exclude>**/InvalidResultSetPointerTest.java</exclude>
                         <exclude>**/RestfulConnectionTest.java</exclude>
-                        <exclude>**/TD4144Test.java</exclude>
+                        <exclude>**/TSDBJNIConnectorTest.java</exclude>
+                        <exclude>**/TaosInfoMonitorTest.java</exclude>
+                        <exclude>**/UnsignedNumberJniTest.java</exclude>
                     </excludes>
                     <testFailureIgnore>true</testFailureIgnore>
                 </configuration>

src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractConnection.java

 package com.taosdata.jdbc;
 
+import com.taosdata.jdbc.enums.TimestampFormat;
+
 import java.sql.*;
 import java.util.Enumeration;
 import java.util.Map;
@@ -18,7 +20,7 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
         for (String propName : propNames) {
             clientInfoProps.setProperty(propName, properties.getProperty(propName));
         }
-        String timestampFormat = properties.getProperty(TSDBDriver.PROPERTY_KEY_TIMESTAMP_FORMAT, "STRING");
+        String timestampFormat = properties.getProperty(TSDBDriver.PROPERTY_KEY_TIMESTAMP_FORMAT, String.valueOf(TimestampFormat.STRING));
         clientInfoProps.setProperty(TSDBDriver.PROPERTY_KEY_TIMESTAMP_FORMAT, timestampFormat);
     }
 
@@ -304,9 +306,6 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
 
     @Override
     public Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException {
-        if (isClosed())
-            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
-
         switch (resultSetHoldability) {
             case ResultSet.HOLD_CURSORS_OVER_COMMIT:
                 break;
@@ -320,11 +319,7 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
     }
 
     @Override
-    public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability)
-            throws SQLException {
-        if (isClosed())
-            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
-
+    public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException {
         switch (resultSetHoldability) {
             case ResultSet.HOLD_CURSORS_OVER_COMMIT:
                 break;
@@ -423,7 +418,7 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
                 status = resultSet.getInt("server_status()");
                 resultSet.close();
             }
-            return status == 1 ? true : false;
+            return status == 1;
         });
 
         boolean status = false;
@@ -432,9 +427,7 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
                 status = future.get();
             else
                 status = future.get(timeout, TimeUnit.SECONDS);
-        } catch (InterruptedException e) {
-            e.printStackTrace();
-        } catch (ExecutionException e) {
+        } catch (InterruptedException | ExecutionException e) {
             e.printStackTrace();
         } catch (TimeoutException e) {
             future.cancel(true);
@@ -450,8 +443,7 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
         if (isClosed)
             throw (SQLClientInfoException) TSDBError.createSQLException(TSDBErrorNumbers.ERROR_SQLCLIENT_EXCEPTION_ON_CONNECTION_CLOSED);
 
-        if (clientInfoProps != null)
-            clientInfoProps.setProperty(name, value);
+        clientInfoProps.setProperty(name, value);
     }
 
     @Override
@@ -459,8 +451,8 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
         if (isClosed)
             throw (SQLClientInfoException) TSDBError.createSQLException(TSDBErrorNumbers.ERROR_SQLCLIENT_EXCEPTION_ON_CONNECTION_CLOSED);
 
-        for (Enumeration<Object> enumer = properties.keys(); enumer.hasMoreElements(); ) {
-            String name = (String) enumer.nextElement();
+        for (Enumeration<Object> enumeration = properties.keys(); enumeration.hasMoreElements(); ) {
+            String name = (String) enumeration.nextElement();
             clientInfoProps.put(name, properties.getProperty(name));
         }
     }
@@ -516,7 +508,6 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
     public void abort(Executor executor) throws SQLException {
         if (isClosed())
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
-
         // do nothing
     }
 
@@ -527,14 +518,13 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
         if (milliseconds < 0)
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_VARIABLE);
 
-        throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNSUPPORTED_METHOD);
+        // do nothing
     }
 
     @Override
     public int getNetworkTimeout() throws SQLException {
         if (isClosed())
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
-
-        throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNSUPPORTED_METHOD);
+        return 0;
     }
 }

src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDriver.java

@@ -58,7 +58,7 @@ public abstract class AbstractDriver implements Driver {
                         value = parameterValuePair.substring(indexOfEqual + 1);
                     }
                 }
-                if ((value != null && value.length() > 0) && (parameter != null && parameter.length() > 0)) {
+                if (value != null && value.length() > 0 && parameter.length() > 0) {
                     urlProps.setProperty(parameter, value);
                 }
             }
@@ -87,7 +87,7 @@ public abstract class AbstractDriver implements Driver {
             url = url.substring(0, indexOfColon);
         }
         // parse host
-        if (url != null && url.length() > 0 && url.trim().length() > 0) {
+        if (url.length() > 0 && url.trim().length() > 0) {
             urlProps.setProperty(TSDBDriver.PROPERTY_KEY_HOST, url);
         }
         return urlProps;

src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractParameterMetaData.java

@@ -49,6 +49,22 @@ public abstract class AbstractParameterMetaData extends WrapperImpl implements P
         if (param < 1 && param >= parameters.length)
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_PARAMETER_INDEX_OUT_RANGE);
 
+        if (parameters[param - 1] instanceof Boolean)
+            return TSDBConstants.BOOLEAN_PRECISION;
+        if (parameters[param - 1] instanceof Byte)
+            return TSDBConstants.TINYINT_PRECISION;
+        if (parameters[param - 1] instanceof Short)
+            return TSDBConstants.SMALLINT_PRECISION;
+        if (parameters[param - 1] instanceof Integer)
+            return TSDBConstants.INT_PRECISION;
+        if (parameters[param - 1] instanceof Long)
+            return TSDBConstants.BIGINT_PRECISION;
+        if (parameters[param - 1] instanceof Timestamp)
+            return TSDBConstants.TIMESTAMP_MS_PRECISION;
+        if (parameters[param - 1] instanceof Float)
+            return TSDBConstants.FLOAT_PRECISION;
+        if (parameters[param - 1] instanceof Double)
+            return TSDBConstants.DOUBLE_PRECISION;
         if (parameters[param - 1] instanceof String)
             return ((String) parameters[param - 1]).length();
         if (parameters[param - 1] instanceof byte[])
@@ -60,6 +76,11 @@ public abstract class AbstractParameterMetaData extends WrapperImpl implements P
     public int getScale(int param) throws SQLException {
         if (param < 1 && param >= parameters.length)
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_PARAMETER_INDEX_OUT_RANGE);
+
+        if (parameters[param - 1] instanceof Float)
+            return TSDBConstants.FLOAT_SCALE;
+        if (parameters[param - 1] instanceof Double)
+            return TSDBConstants.DOUBLE_SCALE;
         return 0;
     }
 

src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractResultSet.java

@@ -66,10 +66,16 @@ public abstract class AbstractResultSet extends WrapperImpl implements ResultSet
     public abstract byte[] getBytes(int columnIndex) throws SQLException;
 
     @Override
-    public abstract Date getDate(int columnIndex) throws SQLException;
+    public Date getDate(int columnIndex) throws SQLException {
+        Timestamp timestamp = getTimestamp(columnIndex);
+        return timestamp == null ? null : new Date(timestamp.getTime());
+    }
 
     @Override
-    public abstract Time getTime(int columnIndex) throws SQLException;
+    public Time getTime(int columnIndex) throws SQLException {
+        Timestamp timestamp = getTimestamp(columnIndex);
+        return timestamp == null ? null : new Time(timestamp.getTime());
+    }
 
     @Override
     public abstract Timestamp getTimestamp(int columnIndex) throws SQLException;

src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractStatement.java

@@ -9,8 +9,6 @@ public abstract class AbstractStatement extends WrapperImpl implements Statement
     protected List<String> batchedArgs;
     private int fetchSize;
 
-
-
     @Override
     public abstract ResultSet executeQuery(String sql) throws SQLException;
 

src/connector/jdbc/src/main/java/com/taosdata/jdbc/EmptyResultSet.java

@@ -23,7 +23,7 @@ import java.util.Calendar;
 import java.util.Map;
 
 /*
- * TDengine only supports a subset of the standard SQL, thus this implemetation of the
+ * TDengine only supports a subset of the standard SQL, thus this implementation of the
  * standard JDBC API contains more or less some adjustments customized for certain
  * compatibility needs.
  */

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConnection.java

@@ -20,7 +20,7 @@ import java.util.Properties;
 public class TSDBConnection extends AbstractConnection {
 
     private TSDBJNIConnector connector;
-    private TSDBDatabaseMetaData databaseMetaData;
+    private final TSDBDatabaseMetaData databaseMetaData;
     private boolean batchFetch;
 
     public Boolean getBatchFetch() {

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConstants.java

@@ -41,22 +41,66 @@ public abstract class TSDBConstants {
     public static final int TSDB_DATA_TYPE_BINARY = 8;
     public static final int TSDB_DATA_TYPE_TIMESTAMP = 9;
     public static final int TSDB_DATA_TYPE_NCHAR = 10;
-    /*
-    系统增加新的无符号数据类型，分别是：
-        unsigned tinyint， 数值范围：0-254, NULL 为255
-        unsigned smallint，数值范围： 0-65534， NULL 为65535
-        unsigned int，数值范围：0-4294967294，NULL 为4294967295u
-        unsigned bigint，数值范围：0-18446744073709551614u，NULL 为18446744073709551615u。
-    example:
-        create table tb(ts timestamp, a tinyint unsigned, b smallint unsigned, c int unsigned, d bigint unsigned);
-    */
+    /**
+     * 系统增加新的无符号数据类型，分别是：
+     * unsigned tinyint， 数值范围：0-254, NULL 为255
+     * unsigned smallint，数值范围： 0-65534， NULL 为65535
+     * unsigned int，数值范围：0-4294967294，NULL 为4294967295u
+     * unsigned bigint，数值范围：0-18446744073709551614u，NULL 为18446744073709551615u。
+     * example:
+     * create table tb(ts timestamp, a tinyint unsigned, b smallint unsigned, c int unsigned, d bigint unsigned);
+     */
     public static final int TSDB_DATA_TYPE_UTINYINT = 11;       //unsigned tinyint
     public static final int TSDB_DATA_TYPE_USMALLINT = 12;      //unsigned smallint
     public static final int TSDB_DATA_TYPE_UINT = 13;           //unsigned int
     public static final int TSDB_DATA_TYPE_UBIGINT = 14;        //unsigned bigint
+
     // nchar column max length
     public static final int maxFieldSize = 16 * 1024;
 
+    // precision for data types, this is used for metadata
+    public static final int BOOLEAN_PRECISION = 1;
+    public static final int TINYINT_PRECISION = 4;
+    public static final int SMALLINT_PRECISION = 6;
+    public static final int INT_PRECISION = 11;
+    public static final int BIGINT_PRECISION = 20;
+    public static final int FLOAT_PRECISION = 12;
+    public static final int DOUBLE_PRECISION = 22;
+    public static final int TIMESTAMP_MS_PRECISION = 23;
+    public static final int TIMESTAMP_US_PRECISION = 26;
+    // scale for data types, this is used for metadata
+    public static final int FLOAT_SCALE = 31;
+    public static final int DOUBLE_SCALE = 31;
+
+    public static final String DEFAULT_PRECISION = "ms";
+
+    public static int typeName2JdbcType(String type) {
+        switch (type.toUpperCase()) {
+            case "TIMESTAMP":
+                return Types.TIMESTAMP;
+            case "INT":
+                return Types.INTEGER;
+            case "BIGINT":
+                return Types.BIGINT;
+            case "FLOAT":
+                return Types.FLOAT;
+            case "DOUBLE":
+                return Types.DOUBLE;
+            case "BINARY":
+                return Types.BINARY;
+            case "SMALLINT":
+                return Types.SMALLINT;
+            case "TINYINT":
+                return Types.TINYINT;
+            case "BOOL":
+                return Types.BOOLEAN;
+            case "NCHAR":
+                return Types.NCHAR;
+            default:
+                return Types.NULL;
+        }
+    }
+
     public static int taosType2JdbcType(int taosType) throws SQLException {
         switch (taosType) {
             case TSDBConstants.TSDB_DATA_TYPE_BOOL:
@@ -88,7 +132,7 @@ public abstract class TSDBConstants {
     }
 
     public static String taosType2JdbcTypeName(int taosType) throws SQLException {
-        switch (taosType){
+        switch (taosType) {
             case TSDBConstants.TSDB_DATA_TYPE_BOOL:
                 return "BOOL";
             case TSDBConstants.TSDB_DATA_TYPE_UTINYINT:
@@ -119,7 +163,7 @@ public abstract class TSDBConstants {
     }
 
     public static int jdbcType2TaosType(int jdbcType) throws SQLException {
-        switch (jdbcType){
+        switch (jdbcType) {
             case Types.BOOLEAN:
                 return TSDBConstants.TSDB_DATA_TYPE_BOOL;
             case Types.TINYINT:
@@ -145,7 +189,7 @@ public abstract class TSDBConstants {
     }
 
     public static String jdbcType2TaosTypeName(int jdbcType) throws SQLException {
-        switch (jdbcType){
+        switch (jdbcType) {
             case Types.BOOLEAN:
                 return "BOOL";
             case Types.TINYINT:

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDatabaseMetaData.java

@@ -20,8 +20,8 @@ import java.sql.SQLException;
 
 public class TSDBDatabaseMetaData extends AbstractDatabaseMetaData {
 
-    private String url;
-    private String userName;
+    private final String url;
+    private final String userName;
     private Connection conn;
 
     public TSDBDatabaseMetaData(String url, String userName) {

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDriver.java

@@ -176,7 +176,7 @@ public class TSDBDriver extends AbstractDriver {
         int beginningOfSlashes = url.indexOf("//");
         int index = url.indexOf("?");
         if (index != -1) {
-            String paramString = url.substring(index + 1, url.length());
+            String paramString = url.substring(index + 1);
             url = url.substring(0, index);
             StringTokenizer queryParams = new StringTokenizer(paramString, "&");
             while (queryParams.hasMoreElements()) {
@@ -213,7 +213,7 @@ public class TSDBDriver extends AbstractDriver {
             url = url.substring(0, indexOfColon);
         }
 
-        if (url != null && url.length() > 0 && url.trim().length() > 0) {
+        if (url.length() > 0 && url.trim().length() > 0) {
             urlProps.setProperty(TSDBDriver.PROPERTY_KEY_HOST, url);
         }
 
@@ -233,7 +233,7 @@ public class TSDBDriver extends AbstractDriver {
         return false;
     }
 
-    public Logger getParentLogger() throws SQLFeatureNotSupportedException {
+    public Logger getParentLogger() {
         return null;
     }
 

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBError.java

@@ -8,7 +8,7 @@ import java.util.HashMap;
 import java.util.Map;
 
 public class TSDBError {
-    private static Map<Integer, String> TSDBErrorMap = new HashMap<>();
+    private static final Map<Integer, String> TSDBErrorMap = new HashMap<>();
 
     static {
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED, "connection already closed");
@@ -32,10 +32,10 @@ public class TSDBError {
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_INVALID_SQL, "invalid sql");
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_NUMERIC_VALUE_OUT_OF_RANGE, "numeric value out of range");
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_UNKNOWN_TAOS_TYPE_IN_TDENGINE, "unknown taos type in tdengine");
+        TSDBErrorMap.put(TSDBErrorNumbers.ERROR_UNKNOWN_TIMESTAMP_PERCISION, "unknown timestamp precision");
 
-        /**************************************************/
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_UNKNOWN, "unknown error");
-        /**************************************************/
+
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_SUBSCRIBE_FAILED, "failed to create subscription");
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_UNSUPPORTED_ENCODING, "Unsupported encoding");
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_JNI_TDENGINE_ERROR, "internal error of database");

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBErrorNumbers.java

 package com.taosdata.jdbc;
 
 import java.util.HashSet;
+import java.util.Set;
 
 public class TSDBErrorNumbers {
 
@@ -25,6 +26,7 @@ public class TSDBErrorNumbers {
     public static final int ERROR_INVALID_SQL = 0x2313;     // invalid sql
     public static final int ERROR_NUMERIC_VALUE_OUT_OF_RANGE = 0x2314;  // numeric value out of range
     public static final int ERROR_UNKNOWN_TAOS_TYPE_IN_TDENGINE = 0x2315; //unknown taos type in tdengine
+    public static final int ERROR_UNKNOWN_TIMESTAMP_PERCISION = 0x2316;     // unknown timestamp precision
 
     public static final int ERROR_UNKNOWN = 0x2350;    //unknown error
 
@@ -38,10 +40,9 @@ public class TSDBErrorNumbers {
     public static final int ERROR_JNI_FETCH_END = 0x2358;       // fetch to the end of resultSet
     public static final int ERROR_JNI_OUT_OF_MEMORY = 0x2359;   // JNI alloc memory failed
 
-    private static final HashSet<Integer> errorNumbers;
+    private static final Set<Integer> errorNumbers = new HashSet();
 
     static {
-        errorNumbers = new HashSet();
         errorNumbers.add(ERROR_CONNECTION_CLOSED);
         errorNumbers.add(ERROR_UNSUPPORTED_METHOD);
         errorNumbers.add(ERROR_INVALID_VARIABLE);
@@ -62,8 +63,8 @@ public class TSDBErrorNumbers {
         errorNumbers.add(ERROR_INVALID_SQL);
         errorNumbers.add(ERROR_NUMERIC_VALUE_OUT_OF_RANGE);
         errorNumbers.add(ERROR_UNKNOWN_TAOS_TYPE_IN_TDENGINE);
+        errorNumbers.add(ERROR_UNKNOWN_TIMESTAMP_PERCISION);
 
-        /*****************************************************/
         errorNumbers.add(ERROR_SUBSCRIBE_FAILED);
         errorNumbers.add(ERROR_UNSUPPORTED_ENCODING);
         errorNumbers.add(ERROR_JNI_TDENGINE_ERROR);

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBJNIConnector.java

@@ -16,27 +16,22 @@
  */
 package com.taosdata.jdbc;
 
+import com.taosdata.jdbc.utils.TaosInfo;
+
 import java.nio.ByteBuffer;
 import java.sql.SQLException;
 import java.sql.SQLWarning;
 import java.util.List;
 
-import com.taosdata.jdbc.utils.TaosInfo;
-
 /**
  * JNI connector
  */
 public class TSDBJNIConnector {
     private static volatile Boolean isInitialized = false;
 
-    private TaosInfo taosInfo = TaosInfo.getInstance();
-    
-    // Connection pointer used in C
-    private long taos = TSDBConstants.JNI_NULL_POINTER;
-    
-    // result set status in current connection
-    private boolean isResultsetClosed;
-
+    private final TaosInfo taosInfo = TaosInfo.getInstance();
+    private long taos = TSDBConstants.JNI_NULL_POINTER;     // Connection pointer used in C
+    private boolean isResultsetClosed;      // result set status in current connection
     private int affectedRows = -1;
 
     static {
@@ -96,11 +91,9 @@ public class TSDBJNIConnector {
 
     /**
      * Execute DML/DDL operation
-     *
-     * @throws SQLException
      */
     public long executeQuery(String sql) throws SQLException {
-        Long pSql = 0l;
+        long pSql = 0L;
         try {
             pSql = this.executeQueryImp(sql.getBytes(TaosGlobalConfig.getCharset()), this.taos);
             taosInfo.stmt_count_increment();
@@ -161,7 +154,7 @@ public class TSDBJNIConnector {
     private native long getResultSetImp(long connection, long pSql);
 
     public boolean isUpdateQuery(long pSql) {
-        return isUpdateQueryImp(this.taos, pSql) == 1 ? true : false;
+        return isUpdateQueryImp(this.taos, pSql) == 1;
     }
 
     private native long isUpdateQueryImp(long connection, long pSql);
@@ -194,7 +187,9 @@ public class TSDBJNIConnector {
      * Get schema metadata
      */
     public int getSchemaMetaData(long resultSet, List<ColumnMetaData> columnMetaData) {
-        return this.getSchemaMetaDataImp(this.taos, resultSet, columnMetaData);
+        int ret = this.getSchemaMetaDataImp(this.taos, resultSet, columnMetaData);
+        columnMetaData.forEach(column -> column.setColIndex(column.getColIndex() + 1));
+        return ret;
     }
 
     private native int getSchemaMetaDataImp(long connection, long resultSet, List<ColumnMetaData> columnMetaData);
@@ -215,13 +210,22 @@ public class TSDBJNIConnector {
     private native int fetchBlockImp(long connection, long resultSet, TSDBResultSetBlockData blockData);
 
     /**
-     * Execute close operation from C to release connection pointer by JNI
+     * Get Result Time Precision.
      *
-     * @throws SQLException
+     * @return 0: ms, 1: us, 2: ns
+     */
+    public int getResultTimePrecision(long sqlObj) {
+        return this.getResultTimePrecisionImp(this.taos, sqlObj);
+    }
+
+    private native int getResultTimePrecisionImp(long connection, long result);
+
+    /**
+     * Execute close operation from C to release connection pointer by JNI
      */
     public void closeConnection() throws SQLException {
         int code = this.closeConnectionImp(this.taos);
-        
+
         if (code < 0) {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_JNI_CONNECTION_NULL);
         } else if (code == 0) {
@@ -229,7 +233,7 @@ public class TSDBJNIConnector {
         } else {
             throw new SQLException("Undefined error code returned by TDengine when closing a connection");
         }
-        
+
         // invoke closeConnectionImpl only here
         taosInfo.connect_close_increment();
     }
@@ -256,8 +260,6 @@ public class TSDBJNIConnector {
 
     /**
      * Unsubscribe, close a subscription
-     *
-     * @param subscription
      */
     void unsubscribe(long subscription, boolean isKeep) {
         unsubscribeImp(subscription, isKeep);
@@ -270,71 +272,80 @@ public class TSDBJNIConnector {
      */
     public boolean validateCreateTableSql(String sql) {
         int res = validateCreateTableSqlImp(taos, sql.getBytes());
-        return res != 0 ? false : true;
+        return res == 0;
     }
 
     private native int validateCreateTableSqlImp(long connection, byte[] sqlBytes);
-    
-	public long prepareStmt(String sql) throws SQLException {
-    	Long stmt = prepareStmtImp(sql.getBytes(), this.taos);
-		if (stmt == TSDBConstants.JNI_TDENGINE_ERROR) {
-			throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_SQL);
-		} else if (stmt == TSDBConstants.JNI_CONNECTION_NULL) {
+
+    public long prepareStmt(String sql) throws SQLException {
+        long stmt;
+        try {
+            stmt = prepareStmtImp(sql.getBytes(), this.taos);
+        } catch (Exception e) {
+            e.printStackTrace();
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNSUPPORTED_ENCODING);
+        }
+
+        if (stmt == TSDBConstants.JNI_CONNECTION_NULL) {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_JNI_CONNECTION_NULL);
-        } else if (stmt == TSDBConstants.JNI_SQL_NULL) {
+        }
+
+        if (stmt == TSDBConstants.JNI_SQL_NULL) {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_JNI_SQL_NULL);
-        } else if (stmt == TSDBConstants.JNI_OUT_OF_MEMORY) {
+        }
+
+        if (stmt == TSDBConstants.JNI_OUT_OF_MEMORY) {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_JNI_OUT_OF_MEMORY);
         }
-        
-    	return stmt;
+
+        return stmt;
     }
-    
+
     private native long prepareStmtImp(byte[] sql, long con);
-    
+
     public void setBindTableName(long stmt, String tableName) throws SQLException {
-		int code = setBindTableNameImp(stmt, tableName, this.taos);
-		if (code != TSDBConstants.JNI_SUCCESS) {
+        int code = setBindTableNameImp(stmt, tableName, this.taos);
+        if (code != TSDBConstants.JNI_SUCCESS) {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNKNOWN, "failed to set table name");
-		}
-	}
-    
+        }
+    }
+
     private native int setBindTableNameImp(long stmt, String name, long conn);
-    
+
     public void setBindTableNameAndTags(long stmt, String tableName, int numOfTags, ByteBuffer tags, ByteBuffer typeList, ByteBuffer lengthList, ByteBuffer nullList) throws SQLException {
-    	int code = setTableNameTagsImp(stmt, tableName, numOfTags, tags.array(), typeList.array(), lengthList.array(), 
-    			nullList.array(), this.taos);
-    	if (code != TSDBConstants.JNI_SUCCESS) {
-    		throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNKNOWN, "failed to bind table name and corresponding tags");
-    	}
+        int code = setTableNameTagsImp(stmt, tableName, numOfTags, tags.array(), typeList.array(), lengthList.array(),
+                nullList.array(), this.taos);
+        if (code != TSDBConstants.JNI_SUCCESS) {
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNKNOWN, "failed to bind table name and corresponding tags");
+        }
     }
-    
+
     private native int setTableNameTagsImp(long stmt, String name, int numOfTags, byte[] tags, byte[] typeList, byte[] lengthList, byte[] nullList, long conn);
-    
-    public void bindColumnDataArray(long stmt, ByteBuffer colDataList, ByteBuffer lengthList, ByteBuffer isNullList, int type, int bytes, int numOfRows,int columnIndex) throws SQLException {
-    	int code = bindColDataImp(stmt, colDataList.array(), lengthList.array(), isNullList.array(), type, bytes, numOfRows, columnIndex, this.taos);
-    	if (code != TSDBConstants.JNI_SUCCESS) {
+
+    public void bindColumnDataArray(long stmt, ByteBuffer colDataList, ByteBuffer lengthList, ByteBuffer isNullList, int type, int bytes, int numOfRows, int columnIndex) throws SQLException {
+        int code = bindColDataImp(stmt, colDataList.array(), lengthList.array(), isNullList.array(), type, bytes, numOfRows, columnIndex, this.taos);
+        if (code != TSDBConstants.JNI_SUCCESS) {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNKNOWN, "failed to bind column data");
-    	}
-	}
-    
+        }
+    }
+
     private native int bindColDataImp(long stmt, byte[] colDataList, byte[] lengthList, byte[] isNullList, int type, int bytes, int numOfRows, int columnIndex, long conn);
-    
+
     public void executeBatch(long stmt) throws SQLException {
-    	int code = executeBatchImp(stmt, this.taos);
-    	if (code != TSDBConstants.JNI_SUCCESS) {
+        int code = executeBatchImp(stmt, this.taos);
+        if (code != TSDBConstants.JNI_SUCCESS) {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNKNOWN, "failed to execute batch bind");
-    	}
+        }
     }
-    
+
     private native int executeBatchImp(long stmt, long con);
-    
+
     public void closeBatch(long stmt) throws SQLException {
-    	int code = closeStmt(stmt, this.taos);
-    	if (code != TSDBConstants.JNI_SUCCESS) {
+        int code = closeStmt(stmt, this.taos);
+        if (code != TSDBConstants.JNI_SUCCESS) {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNKNOWN, "failed to close batch bind");
-    	}
+        }
     }
-    
+
     private native int closeStmt(long stmt, long con);
 }

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSet.java

@@ -133,9 +133,10 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return this.blockData.getString(columnIndex - 1);
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
         if (!lastWasNull) {
-            res = this.rowData.getString(columnIndex - 1, this.columnMetaDataList.get(columnIndex - 1).getColType());
+            int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+            res = this.rowData.getString(columnIndex, nativeType);
         }
         return res;
     }
@@ -147,9 +148,10 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return this.blockData.getBoolean(columnIndex - 1);
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
         if (!lastWasNull) {
-            res = this.rowData.getBoolean(columnIndex - 1, this.columnMetaDataList.get(columnIndex - 1).getColType());
+            int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+            res = this.rowData.getBoolean(columnIndex, nativeType);
         }
         return res;
     }
@@ -161,9 +163,10 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return (byte) this.blockData.getInt(columnIndex - 1);
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
         if (!lastWasNull) {
-            res = (byte) this.rowData.getInt(columnIndex - 1, this.columnMetaDataList.get(columnIndex - 1).getColType());
+            int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+            res = (byte) this.rowData.getInt(columnIndex, nativeType);
         }
         return res;
     }
@@ -175,9 +178,10 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return (short) this.blockData.getInt(columnIndex - 1);
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
         if (!lastWasNull) {
-            res = (short) this.rowData.getInt(columnIndex - 1, this.columnMetaDataList.get(columnIndex - 1).getColType());
+            int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+            res = (short) this.rowData.getInt(columnIndex, nativeType);
         }
         return res;
     }
@@ -189,9 +193,11 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return this.blockData.getInt(columnIndex - 1);
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
+
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
         if (!lastWasNull) {
-            res = this.rowData.getInt(columnIndex - 1, this.columnMetaDataList.get(columnIndex - 1).getColType());
+            int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+            res = this.rowData.getInt(columnIndex, nativeType);
         }
         return res;
     }
@@ -203,13 +209,15 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return this.blockData.getLong(columnIndex - 1);
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
         if (!lastWasNull) {
-            Object value = this.rowData.get(columnIndex - 1);
-            if (value instanceof Timestamp)
+            Object value = this.rowData.getObject(columnIndex);
+            if (value instanceof Timestamp) {
                 res = ((Timestamp) value).getTime();
-            else
-                res = this.rowData.getLong(columnIndex - 1, this.columnMetaDataList.get(columnIndex - 1).getColType());
+            } else {
+                int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+                res = this.rowData.getLong(columnIndex, nativeType);
+            }
         }
         return res;
     }
@@ -221,9 +229,11 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return (float) this.blockData.getDouble(columnIndex - 1);
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
-        if (!lastWasNull)
-            res = this.rowData.getFloat(columnIndex - 1, this.columnMetaDataList.get(columnIndex - 1).getColType());
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
+        if (!lastWasNull) {
+            int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+            res = this.rowData.getFloat(columnIndex, nativeType);
+        }
 
         return res;
     }
@@ -235,9 +245,10 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return this.blockData.getDouble(columnIndex - 1);
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
         if (!lastWasNull) {
-            res = this.rowData.getDouble(columnIndex - 1, this.columnMetaDataList.get(columnIndex - 1).getColType());
+            int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+            res = this.rowData.getDouble(columnIndex, nativeType);
         }
         return res;
     }
@@ -245,34 +256,27 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
     public byte[] getBytes(int columnIndex) throws SQLException {
         checkAvailability(columnIndex, this.columnMetaDataList.size());
 
-        Object value = this.rowData.get(columnIndex - 1);
+        Object value = this.rowData.getObject(columnIndex);
         if (value == null)
             return null;
 
-        int colType = this.columnMetaDataList.get(columnIndex - 1).getColType();
-        switch (colType) {
+        int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+        switch (nativeType) {
             case TSDBConstants.TSDB_DATA_TYPE_BIGINT:
-                return Longs.toByteArray((Long) value);
+                return Longs.toByteArray((long) value);
             case TSDBConstants.TSDB_DATA_TYPE_INT:
                 return Ints.toByteArray((int) value);
             case TSDBConstants.TSDB_DATA_TYPE_SMALLINT:
-                return Shorts.toByteArray((Short) value);
+                return Shorts.toByteArray((short) value);
             case TSDBConstants.TSDB_DATA_TYPE_TINYINT:
                 return new byte[]{(byte) value};
+            case TSDBConstants.TSDB_DATA_TYPE_BINARY:
+                return (byte[]) value;
+            case TSDBConstants.TSDB_DATA_TYPE_BOOL:
+            case TSDBConstants.TSDB_DATA_TYPE_NCHAR:
+            default:
+                return value.toString().getBytes();
         }
-        return value.toString().getBytes();
-    }
-
-    @Override
-    public Date getDate(int columnIndex) throws SQLException {
-        Timestamp timestamp = getTimestamp(columnIndex);
-        return timestamp == null ? null : new Date(timestamp.getTime());
-    }
-
-    @Override
-    public Time getTime(int columnIndex) throws SQLException {
-        Timestamp timestamp = getTimestamp(columnIndex);
-        return timestamp == null ? null : new Time(timestamp.getTime());
     }
 
     public Timestamp getTimestamp(int columnIndex) throws SQLException {
@@ -282,9 +286,10 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return this.blockData.getTimestamp(columnIndex - 1);
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
         if (!lastWasNull) {
-            res = this.rowData.getTimestamp(columnIndex - 1);
+            int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+            res = this.rowData.getTimestamp(columnIndex, nativeType);
         }
         return res;
     }
@@ -304,13 +309,9 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return this.blockData.get(columnIndex - 1);
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
         if (!lastWasNull) {
-            int colType = this.columnMetaDataList.get(columnIndex - 1).getColType();
-            if (colType == TSDBConstants.TSDB_DATA_TYPE_BINARY)
-                res = ((String) this.rowData.get(columnIndex - 1)).getBytes();
-            else
-                res = this.rowData.get(columnIndex - 1);
+            res = this.rowData.getObject(columnIndex);
         }
         return res;
     }
@@ -318,7 +319,7 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
     public int findColumn(String columnLabel) throws SQLException {
         for (ColumnMetaData colMetaData : this.columnMetaDataList) {
             if (colMetaData.getColName() != null && colMetaData.getColName().equalsIgnoreCase(columnLabel)) {
-                return colMetaData.getColIndex() + 1;
+                return colMetaData.getColIndex();
             }
         }
         throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_VARIABLE);
@@ -329,25 +330,25 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
         if (this.getBatchFetch())
             return new BigDecimal(this.blockData.getLong(columnIndex - 1));
 
-        this.lastWasNull = this.rowData.wasNull(columnIndex - 1);
+        this.lastWasNull = this.rowData.wasNull(columnIndex);
         BigDecimal res = null;
         if (!lastWasNull) {
-            int colType = this.columnMetaDataList.get(columnIndex - 1).getColType();
-            switch (colType) {
+            int nativeType = this.columnMetaDataList.get(columnIndex - 1).getColType();
+            switch (nativeType) {
                 case TSDBConstants.TSDB_DATA_TYPE_TINYINT:
                 case TSDBConstants.TSDB_DATA_TYPE_SMALLINT:
                 case TSDBConstants.TSDB_DATA_TYPE_INT:
                 case TSDBConstants.TSDB_DATA_TYPE_BIGINT:
-                    res = new BigDecimal(Long.valueOf(this.rowData.get(columnIndex - 1).toString()));
+                    res = new BigDecimal(Long.parseLong(this.rowData.getObject(columnIndex).toString()));
                     break;
                 case TSDBConstants.TSDB_DATA_TYPE_FLOAT:
                 case TSDBConstants.TSDB_DATA_TYPE_DOUBLE:
-                    res = new BigDecimal(Double.valueOf(this.rowData.get(columnIndex - 1).toString()));
+                    res = BigDecimal.valueOf(Double.parseDouble(this.rowData.getObject(columnIndex).toString()));
                     break;
                 case TSDBConstants.TSDB_DATA_TYPE_TIMESTAMP:
-                    return new BigDecimal(((Timestamp) this.rowData.get(columnIndex - 1)).getTime());
+                    return new BigDecimal(((Timestamp) this.rowData.getObject(columnIndex)).getTime());
                 default:
-                    res = new BigDecimal(this.rowData.get(columnIndex - 1).toString());
+                    res = new BigDecimal(this.rowData.getObject(columnIndex).toString());
             }
         }
         return res;

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetBlockData.java

@@ -36,23 +36,20 @@ public class TSDBResultSetBlockData {
     private int rowIndex = 0;
 
     private List<ColumnMetaData> columnMetaDataList;
-    private ArrayList<Object> colData = null;
+    private ArrayList<Object> colData;
 
     public TSDBResultSetBlockData(List<ColumnMetaData> colMeta, int numOfCols) {
         this.columnMetaDataList = colMeta;
-        this.colData = new ArrayList<Object>(numOfCols);
+        this.colData = new ArrayList<>(numOfCols);
     }
 
     public TSDBResultSetBlockData() {
-        this.colData = new ArrayList<Object>();
+        this.colData = new ArrayList<>();
     }
 
     public void clear() {
         int size = this.colData.size();
-        if (this.colData != null) {
-            this.colData.clear();
-        }
-
+        this.colData.clear();
         setNumOfCols(size);
     }
 
@@ -69,7 +66,7 @@ public class TSDBResultSetBlockData {
     }
 
     public void setNumOfCols(int numOfCols) {
-        this.colData = new ArrayList<Object>(numOfCols);
+        this.colData = new ArrayList<>(numOfCols);
         this.colData.addAll(Collections.nCopies(numOfCols, null));
     }
 
@@ -166,15 +163,10 @@ public class TSDBResultSetBlockData {
         }
     }
 
-    
 
     /**
      * The original type may not be a string type, but will be converted to by
      * calling this method
-     *
-     * @param col column index
-     * @return
-     * @throws SQLException
      */
     public String getString(int col) throws SQLException {
         Object obj = get(col);
@@ -387,7 +379,7 @@ public class TSDBResultSetBlockData {
                     return null;
                 }
 
-                return (long) val;
+                return val;
             }
 
             case TSDBConstants.TSDB_DATA_TYPE_FLOAT: {

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetMetaData.java

@@ -41,10 +41,7 @@ public class TSDBResultSetMetaData extends WrapperImpl implements ResultSetMetaD
     }
 
     public boolean isSearchable(int column) throws SQLException {
-        if (column == 1) {
-            return true;
-        }
-        return false;
+        return column == 1;
     }
 
     public boolean isCurrency(int column) throws SQLException {
@@ -113,6 +110,7 @@ public class TSDBResultSetMetaData extends WrapperImpl implements ResultSetMetaD
 
         ColumnMetaData columnMetaData = this.colMetaDataList.get(column - 1);
         switch (columnMetaData.getColType()) {
+            
             case TSDBConstants.TSDB_DATA_TYPE_FLOAT:
                 return 5;
             case TSDBConstants.TSDB_DATA_TYPE_DOUBLE:

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBStatement.java

@@ -32,14 +32,15 @@ public class TSDBStatement extends AbstractStatement {
     }
 
     public ResultSet executeQuery(String sql) throws SQLException {
-        // check if closed
         if (isClosed()) {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_STATEMENT_CLOSED);
         }
-        
-        //TODO: 如果在executeQuery方法中执行insert语句，那么先执行了SQL，再通过pSql来检查是否为一个insert语句，但这个insert SQL已经执行成功了
-
-        // execute query
+        //TODO:
+        // this is an unreasonable implementation, if the paratemer is a insert statement,
+        // the JNI connector will execute the sql at first and return a pointer: pSql,
+        // we use this pSql and invoke the isUpdateQuery(long pSql) method to decide .
+        // but the insert sql is already executed in database.
+        //execute query
         long pSql = this.connection.getConnector().executeQuery(sql);
         // if pSql is create/insert/update/delete/alter SQL
         if (this.connection.getConnector().isUpdateQuery(pSql)) {

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java

@@ -47,9 +47,6 @@ public class TSDBSubscribe {
 
     /**
      * close subscription
-     *
-     * @param keepProgress
-     * @throws SQLException
      */
     public void close(boolean keepProgress) throws SQLException {
         if (this.connecter.isClosed())

src/connector/jdbc/src/main/java/com/taosdata/jdbc/enums/TimestampFormat.java

+package com.taosdata.jdbc.enums;
+
+public enum TimestampFormat {
+    STRING,
+    TIMESTAMP,
+    UTC
+}

src/connector/jdbc/src/main/java/com/taosdata/jdbc/enums/TimestampPrecision.java

+package com.taosdata.jdbc.enums;
+
+public enum TimestampPrecision {
+    MS,
+    US,
+    NS,
+    UNKNOWN
+}

src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulConnection.java

@@ -16,17 +16,19 @@ public class RestfulConnection extends AbstractConnection {
     private final String host;
     private final int port;
     private final String url;
-    private volatile String database;
+    private final String database;
+    private final String token;
     /******************************************************/
     private boolean isClosed;
     private final DatabaseMetaData metadata;
 
-    public RestfulConnection(String host, String port, Properties props, String database, String url) {
+    public RestfulConnection(String host, String port, Properties props, String database, String url, String token) {
         super(props);
         this.host = host;
         this.port = Integer.parseInt(port);
         this.database = database;
         this.url = url;
+        this.token = token;
         this.metadata = new RestfulDatabaseMetaData(url, props.getProperty(TSDBDriver.PROPERTY_KEY_USER), this);
     }
 
@@ -66,6 +68,7 @@ public class RestfulConnection extends AbstractConnection {
         return this.metadata;
     }
 
+    // getters
     public String getHost() {
         return host;
     }
@@ -81,4 +84,8 @@ public class RestfulConnection extends AbstractConnection {
     public String getUrl() {
         return url;
     }
+
+    public String getToken() {
+        return token;
+    }
 }
\ No newline at end of file

src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulDriver.java

@@ -38,15 +38,11 @@ public class RestfulDriver extends AbstractDriver {
         String port = props.getProperty(TSDBDriver.PROPERTY_KEY_PORT, "6041");
         String database = props.containsKey(TSDBDriver.PROPERTY_KEY_DBNAME) ? props.getProperty(TSDBDriver.PROPERTY_KEY_DBNAME) : null;
 
-        String loginUrl = "http://" + props.getProperty(TSDBDriver.PROPERTY_KEY_HOST) + ":"
-                + props.getProperty(TSDBDriver.PROPERTY_KEY_PORT) + "/rest/login/"
-                + props.getProperty(TSDBDriver.PROPERTY_KEY_USER) + "/"
-                + props.getProperty(TSDBDriver.PROPERTY_KEY_PASSWORD) + "";
+        String loginUrl = "http://" + host + ":" + port + "/rest/login/" + props.getProperty(TSDBDriver.PROPERTY_KEY_USER) + "/" + props.getProperty(TSDBDriver.PROPERTY_KEY_PASSWORD) + "";
         try {
             String user = URLEncoder.encode(props.getProperty(TSDBDriver.PROPERTY_KEY_USER), "UTF-8");
             String password = URLEncoder.encode(props.getProperty(TSDBDriver.PROPERTY_KEY_PASSWORD), "UTF-8");
-            loginUrl = "http://" + props.getProperty(TSDBDriver.PROPERTY_KEY_HOST) + ":"
-                    + props.getProperty(TSDBDriver.PROPERTY_KEY_PORT) + "/rest/login/" + user + "/" + password + "";
+            loginUrl = "http://" + props.getProperty(TSDBDriver.PROPERTY_KEY_HOST) + ":" + props.getProperty(TSDBDriver.PROPERTY_KEY_PORT) + "/rest/login/" + user + "/" + password + "";
         } catch (UnsupportedEncodingException e) {
             e.printStackTrace();
         }
@@ -55,12 +51,12 @@ public class RestfulDriver extends AbstractDriver {
         JSONObject jsonResult = JSON.parseObject(result);
         String status = jsonResult.getString("status");
         String token = jsonResult.getString("desc");
-        HttpClientPoolUtil.token = token;
+
         if (!status.equals("succ")) {
             throw new SQLException(jsonResult.getString("desc"));
         }
 
-        RestfulConnection conn = new RestfulConnection(host, port, props, database, url);
+        RestfulConnection conn = new RestfulConnection(host, port, props, database, url, token);
         if (database != null && !database.trim().replaceAll("\\s", "").isEmpty()) {
             Statement stmt = conn.createStatement();
             stmt.execute("use " + database);

src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulPreparedStatement.java

@@ -13,7 +13,7 @@ import java.util.Calendar;
 
 public class RestfulPreparedStatement extends RestfulStatement implements PreparedStatement {
 
-    private ParameterMetaData parameterMetaData;
+    private final ParameterMetaData parameterMetaData;
     private final String rawSql;
     private Object[] parameters;
     private boolean isPrepared;
@@ -44,7 +44,7 @@ public class RestfulPreparedStatement extends RestfulStatement implements Prepar
         if (!isPrepared)
             return executeQuery(this.rawSql);
 
-        final String sql = getNativeSql(this.rawSql);
+        final String sql = Utils.getNativeSql(this.rawSql, this.parameters);
         return executeQuery(sql);
     }
 
@@ -55,20 +55,10 @@ public class RestfulPreparedStatement extends RestfulStatement implements Prepar
         if (!isPrepared)
             return executeUpdate(this.rawSql);
 
-        final String sql = getNativeSql(this.rawSql);
+        final String sql = Utils.getNativeSql(rawSql, this.parameters);
         return executeUpdate(sql);
     }
 
-    /****
-     * 将rawSql转换成一条可执行的sql语句，使用属性parameters中的变脸进行替换
-     * 对于insert into ?.? (?,?,?) using ?.? (?,?,?) tags(?, ?, ?) values(?, ?, ?)
-     * @param rawSql，可能是insert、select或其他，使用?做占位符
-     * @return
-     */
-    private String getNativeSql(String rawSql) {
-        return Utils.getNativeSql(rawSql, this.parameters);
-    }
-
     @Override
     public void setNull(int parameterIndex, int sqlType) throws SQLException {
         if (isClosed())
@@ -224,16 +214,13 @@ public class RestfulPreparedStatement extends RestfulStatement implements Prepar
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_STATEMENT_CLOSED);
         if (!isPrepared)
             return execute(this.rawSql);
-        final String sql = getNativeSql(rawSql);
+        final String sql = Utils.getNativeSql(rawSql, this.parameters);
         return execute(sql);
     }
 
     @Override
     public void addBatch() throws SQLException {
-        if (isClosed())
-            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_STATEMENT_CLOSED);
-
-        final String sql = getNativeSql(this.rawSql);
+        final String sql = Utils.getNativeSql(rawSql, this.parameters);
         addBatch(sql);
     }
 

src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulResultSetMetaData.java

@@ -7,21 +7,20 @@ import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.sql.Timestamp;
 import java.sql.Types;
-import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 
 public class RestfulResultSetMetaData extends WrapperImpl implements ResultSetMetaData {
 
     private final String database;
-    private ArrayList<RestfulResultSet.Field> fields;
-    private final RestfulResultSet resultSet;
+    private final List<RestfulResultSet.Field> fields;
 
-    public RestfulResultSetMetaData(String database, ArrayList<RestfulResultSet.Field> fields, RestfulResultSet resultSet) {
+    public RestfulResultSetMetaData(String database, List<RestfulResultSet.Field> fields, RestfulResultSet resultSet) {
         this.database = database;
-        this.fields = fields;
-        this.resultSet = resultSet;
+        this.fields = fields == null ? Collections.emptyList() : fields;
     }
 
-    public ArrayList<RestfulResultSet.Field> getFields() {
+    public List<RestfulResultSet.Field> getFields() {
         return fields;
     }
 
@@ -139,8 +138,8 @@ public class RestfulResultSetMetaData extends WrapperImpl implements ResultSetMe
 
     @Override
     public String getColumnTypeName(int column) throws SQLException {
-        int taos_type = fields.get(column - 1).taos_type;
-        return TSDBConstants.taosType2JdbcTypeName(taos_type);
+        int taosType = fields.get(column - 1).taos_type;
+        return TSDBConstants.taosType2JdbcTypeName(taosType);
     }
 
     @Override

src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/SqlSyntaxValidator.java

@@ -14,10 +14,6 @@
  *****************************************************************************/
 package com.taosdata.jdbc.utils;
 
-import com.taosdata.jdbc.TSDBConnection;
-
-import java.sql.Connection;
-
 public class SqlSyntaxValidator {
 
     private static final String[] SQL = {"select", "insert", "import", "create", "use", "alter", "drop", "set", "show", "describe"};
@@ -26,12 +22,6 @@ public class SqlSyntaxValidator {
 
     private static final String[] databaseUnspecifiedShow = {"databases", "dnodes", "mnodes", "variables"};
 
-    private TSDBConnection tsdbConnection;
-
-    public SqlSyntaxValidator(Connection connection) {
-        this.tsdbConnection = (TSDBConnection) connection;
-    }
-
     public static boolean isValidForExecuteUpdate(String sql) {
         for (String prefix : updateSQL) {
             if (sql.trim().toLowerCase().startsWith(prefix))

src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/AuthenticationTest.java → src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/AuthenticationTest.java

-package com.taosdata.jdbc.rs;
+package com.taosdata.jdbc.cases;
 
 import org.junit.Before;
 import org.junit.Test;

src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/TwoTypeTimestampPercisionInRestfulTest.java → src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MicroSecondPrecisionRestfulTest.java

@@ -10,10 +10,9 @@ import org.junit.Test;
 import java.sql.*;
 import java.util.Properties;
 
-public class TwoTypeTimestampPercisionInRestfulTest {
+public class MicroSecondPrecisionRestfulTest {
 
     private static final String host = "127.0.0.1";
-
     private static final String ms_timestamp_db = "ms_precision_test";
     private static final String us_timestamp_db = "us_precision_test";
     private static final long timestamp1 = System.currentTimeMillis();