change

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

@@ -981,9 +981,7 @@ public abstract class AbstractDatabaseMetaData implements DatabaseMetaData, Wrap
         return getEmptyResultSet();
     }
 
-    public Connection getConnection() throws SQLException {
-        return null;
-    }
+    public abstract Connection getConnection() throws SQLException;
 
     public boolean supportsSavepoints() throws SQLException {
         return false;

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

@@ -90,7 +90,7 @@ public class TSDBDriver extends AbstractDriver {
      * fetch data from native function in a batch model
      */
     public static final String PROPERTY_KEY_BATCH_LOAD = "batchfetch";
-    
+
     private TSDBDatabaseMetaData dbMetaData = null;
 
     static {
@@ -179,18 +179,18 @@ public class TSDBDriver extends AbstractDriver {
             while (queryParams.hasMoreElements()) {
                 String oneToken = queryParams.nextToken();
                 String[] pair = oneToken.split("=");
-                
+
                 if ((pair[0] != null && pair[0].trim().length() > 0) && (pair[1] != null && pair[1].trim().length() > 0)) {
                     urlProps.setProperty(pair[0].trim(), pair[1].trim());
                 }
             }
         }
-        
+
         // parse Product Name
         String dbProductName = url.substring(0, beginningOfSlashes);
         dbProductName = dbProductName.substring(dbProductName.indexOf(":") + 1);
         dbProductName = dbProductName.substring(0, dbProductName.indexOf(":"));
-        
+
         // parse database name
         url = url.substring(beginningOfSlashes + 2);
         int indexOfSlash = url.indexOf("/");
@@ -200,7 +200,7 @@ public class TSDBDriver extends AbstractDriver {
             }
             url = url.substring(0, indexOfSlash);
         }
-        
+
         // parse port
         int indexOfColon = url.indexOf(":");
         if (indexOfColon != -1) {
@@ -209,11 +209,11 @@ public class TSDBDriver extends AbstractDriver {
             }
             url = url.substring(0, indexOfColon);
         }
-        
+
         if (url != null && url.length() > 0 && url.trim().length() > 0) {
             urlProps.setProperty(TSDBDriver.PROPERTY_KEY_HOST, url);
         }
-        
+
         this.dbMetaData = new TSDBDatabaseMetaData(urlForMeta, urlProps.getProperty(TSDBDriver.PROPERTY_KEY_USER));
         return urlProps;
     }

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

 package com.taosdata.jdbc.rs;
 
 import com.taosdata.jdbc.AbstractDatabaseMetaData;
-import com.taosdata.jdbc.TSDBConstants;
+import com.taosdata.jdbc.TSDBError;
+import com.taosdata.jdbc.TSDBErrorNumbers;
 
 import java.sql.Connection;
 import java.sql.ResultSet;
@@ -34,11 +35,10 @@ public class RestfulDatabaseMetaData extends AbstractDatabaseMetaData {
         return RestfulDriver.class.getName();
     }
 
-
     @Override
     public ResultSet getTables(String catalog, String schemaPattern, String tableNamePattern, String[] types) throws SQLException {
         if (connection == null || connection.isClosed()) {
-            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
         }
         return super.getTables(catalog, schemaPattern, tableNamePattern, types, connection);
     }
@@ -46,14 +46,14 @@ public class RestfulDatabaseMetaData extends AbstractDatabaseMetaData {
     @Override
     public ResultSet getCatalogs() throws SQLException {
         if (connection == null || connection.isClosed())
-            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
         return super.getCatalogs(connection);
     }
 
     @Override
     public ResultSet getTableTypes() throws SQLException {
         if (connection == null || connection.isClosed()) {
-            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
         }
         return super.getTableTypes();
     }
@@ -61,21 +61,26 @@ public class RestfulDatabaseMetaData extends AbstractDatabaseMetaData {
     @Override
     public ResultSet getColumns(String catalog, String schemaPattern, String tableNamePattern, String columnNamePattern) throws SQLException {
         if (connection == null || connection.isClosed())
-            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
         return super.getColumns(catalog, schemaPattern, tableNamePattern, columnNamePattern, connection);
     }
 
     @Override
     public ResultSet getPrimaryKeys(String catalog, String schema, String table) throws SQLException {
         if (connection == null || connection.isClosed())
-            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
         return super.getPrimaryKeys(catalog, schema, table, connection);
     }
 
+    @Override
+    public Connection getConnection() throws SQLException {
+        return this.connection;
+    }
+
     @Override
     public ResultSet getSuperTables(String catalog, String schemaPattern, String tableNamePattern) throws SQLException {
         if (connection == null || connection.isClosed())
-            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
         return super.getSuperTables(catalog, schemaPattern, tableNamePattern, connection);
     }