fix: adapter 3.0 (#20391)

docs/examples/java/src/main/java/com/taos/example/highvolume/DataBaseMonitor.java

@@ -36,28 +36,17 @@ public class DataBaseMonitor {
         stmt.execute("CREATE STABLE test.meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (location BINARY(64), groupId INT)");
     }
 
-    public Long count() throws SQLException {
-        if (!stmt.isClosed()) {
-            ResultSet result = stmt.executeQuery("SELECT count(*) from test.meters");
+    public long count() throws SQLException {
+        try (ResultSet result = stmt.executeQuery("SELECT count(*) from test.meters")) {
             result.next();
             return result.getLong(1);
         }
-        return null;
     }
 
-    /**
-     * show test.stables;
-     *
-     *               name              |      created_time       | columns |  tags  |   tables    |
-     * ============================================================================================
-     *  meters                         | 2022-07-20 08:39:30.902 |       4 |      2 |      620000 |
-     */
-    public  Long getTableCount() throws SQLException {
-        if (!stmt.isClosed()) {
-            ResultSet result = stmt.executeQuery("show test.stables");
+    public long getTableCount() throws SQLException {
+        try (ResultSet result = stmt.executeQuery("select count(*) from information_schema.ins_tables where db_name = 'test';")) {
             result.next();
-            return result.getLong(5);
+            return result.getLong(1);
         }
-        return null;
     }
 }
\ No newline at end of file

docs/examples/java/src/main/java/com/taos/example/highvolume/SQLWriter.java

@@ -42,7 +42,7 @@ public class SQLWriter {
     /**
      * Maximum SQL length.
      */
-    private int maxSQLLength;
+    private int maxSQLLength = 800_000;
 
     /**
      * Map from table name to column values. For example:
@@ -81,14 +81,6 @@ public class SQLWriter {
         conn = getConnection();
         stmt = conn.createStatement();
         stmt.execute("use test");
-        ResultSet rs = stmt.executeQuery("show variables");
-        while (rs.next()) {
-            String configName = rs.getString(1);
-            if ("maxSQLLength".equals(configName)) {
-                maxSQLLength = Integer.parseInt(rs.getString(2));
-                logger.info("maxSQLLength={}", maxSQLLength);
-            }
-        }
     }
 
     /**
@@ -149,7 +141,7 @@ public class SQLWriter {
         } catch (SQLException e) {
             // convert to error code defined in taoserror.h
             int errorCode = e.getErrorCode() & 0xffff;
-            if (errorCode == 0x362 || errorCode == 0x218) {
+            if (errorCode == 0x2603) {
                 // Table does not exist
                 createTables();
                 executeSQL(sql);