diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDatabaseMetaData.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDatabaseMetaData.java
index 0d9239d4a0..5dcaa77ebd 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDatabaseMetaData.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDatabaseMetaData.java
@@ -4,7 +4,7 @@ import java.sql.*;
 import java.util.ArrayList;
 import java.util.List;
 
-public abstract class AbstractDatabaseMetaData implements DatabaseMetaData, Wrapper {
+public abstract class AbstractDatabaseMetaData extends WrapperImpl implements DatabaseMetaData {
 
     private final static String PRODUCT_NAME = "TDengine";
     private final static String PRODUCT_VESION = "2.0.x.x";
@@ -1092,20 +1092,6 @@ public abstract class AbstractDatabaseMetaData implements DatabaseMetaData, Wrap
         return new EmptyResultSet();
     }
 
-    @Override
-    public <T> T unwrap(Class<T> iface) throws SQLException {
-        try {
-            return iface.cast(this);
-        } catch (ClassCastException cce) {
-            throw new SQLException("Unable to unwrap to " + iface.toString());
-        }
-    }
-
-    @Override
-    public boolean isWrapperFor(Class<?> iface) throws SQLException {
-        return iface.isInstance(this);
-    }
-
     protected ResultSet getCatalogs(Connection conn) throws SQLException {
         try (Statement stmt = conn.createStatement()) {
             DatabaseMetaDataResultSet resultSet = new DatabaseMetaDataResultSet();
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBError.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBError.java
index 84db5b6992..ce1fcaae5a 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBError.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBError.java
@@ -18,6 +18,10 @@ public class TSDBError {
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_BATCH_IS_EMPTY, "Batch is empty!");
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_INVALID_WITH_EXECUTEQUERY, "Can not issue data manipulation statements with executeQuery()");
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_INVALID_WITH_EXECUTEUPDATE, "Can not issue SELECT via executeUpdate()");
+        TSDBErrorMap.put(TSDBErrorNumbers.ERROR_INVALID_FOR_EXECUTE_QUERY, "not a valid sql for executeQuery: (?)");
+        TSDBErrorMap.put(TSDBErrorNumbers.ERROR_DATABASE_NOT_SPECIFIED_OR_AVAILABLE, "Database not specified or available");
+        TSDBErrorMap.put(TSDBErrorNumbers.ERROR_INVALID_FOR_EXECUTE_UPDATE, "not a valid sql for executeUpdate: (?)");
+        TSDBErrorMap.put(TSDBErrorNumbers.ERROR_INVALID_FOR_EXECUTE, "not a valid sql for execute: (?)");
 
         /**************************************************/
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_UNKNOWN, "unknown error");
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBErrorNumbers.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBErrorNumbers.java
index 51a3f908dc..9a4effb8ee 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBErrorNumbers.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBErrorNumbers.java
@@ -12,6 +12,10 @@ public class TSDBErrorNumbers {
     public static final int ERROR_BATCH_IS_EMPTY = 0x2306;      //Batch is empty!
     public static final int ERROR_INVALID_WITH_EXECUTEQUERY = 0x2307;  //Can not issue data manipulation statements with executeQuery()
     public static final int ERROR_INVALID_WITH_EXECUTEUPDATE = 0x2308; //Can not issue SELECT via executeUpdate()
+    public static final int ERROR_INVALID_FOR_EXECUTE_QUERY = 0x2309;  //not a valid sql for executeQuery: (SQL)
+    public static final int ERROR_DATABASE_NOT_SPECIFIED_OR_AVAILABLE = 0x2310; //Database not specified or available
+    public static final int ERROR_INVALID_FOR_EXECUTE_UPDATE = 0x2311;  //not a valid sql for executeUpdate: (SQL)
+    public static final int ERROR_INVALID_FOR_EXECUTE = 0x2312;         //not a valid sql for execute: (SQL)
 
     public static final int ERROR_UNKNOWN = 0x2350;    //unknown error
 
@@ -37,6 +41,11 @@ public class TSDBErrorNumbers {
         errorNumbers.add(ERROR_RESULTSET_CLOSED);
         errorNumbers.add(ERROR_INVALID_WITH_EXECUTEQUERY);
         errorNumbers.add(ERROR_INVALID_WITH_EXECUTEUPDATE);
+        errorNumbers.add(ERROR_INVALID_FOR_EXECUTE_QUERY);
+        errorNumbers.add(ERROR_DATABASE_NOT_SPECIFIED_OR_AVAILABLE);
+        errorNumbers.add(ERROR_INVALID_FOR_EXECUTE_UPDATE);
+        errorNumbers.add(ERROR_INVALID_FOR_EXECUTE);
+
         /*****************************************************/
         errorNumbers.add(ERROR_SUBSCRIBE_FAILED);
         errorNumbers.add(ERROR_UNSUPPORTED_ENCODING);
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java
index 84d23ad45c..c21a058ba2 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java
@@ -16,9 +16,6 @@ package com.taosdata.jdbc;
 
 import javax.management.OperationsException;
 import java.sql.SQLException;
-import java.util.Map;
-import java.util.TimerTask;
-import java.util.concurrent.*;
 
 public class TSDBSubscribe {
     private TSDBJNIConnector connecter = null;
@@ -36,9 +33,8 @@ public class TSDBSubscribe {
     /**
      * consume
      *
-     * @throws OperationsException, SQLException
      */
-    public TSDBResultSet consume() throws OperationsException, SQLException {
+    public TSDBResultSet consume() throws SQLException {
         if (this.connecter.isClosed()) {
             throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
         }
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulStatement.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulStatement.java
index 8a38690d60..f10d914859 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulStatement.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulStatement.java
@@ -4,6 +4,8 @@ import com.alibaba.fastjson.JSON;
 import com.alibaba.fastjson.JSONObject;
 import com.taosdata.jdbc.AbstractStatement;
 import com.taosdata.jdbc.TSDBConstants;
+import com.taosdata.jdbc.TSDBError;
+import com.taosdata.jdbc.TSDBErrorNumbers;
 import com.taosdata.jdbc.rs.util.HttpClientPoolUtil;
 import com.taosdata.jdbc.utils.SqlSyntaxValidator;
 
@@ -63,9 +65,9 @@ public class RestfulStatement extends AbstractStatement {
     @Override
     public ResultSet executeQuery(String sql) throws SQLException {
         if (isClosed())
-            throw new SQLException("statement already closed");
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_STATEMENT_CLOSED);
         if (!SqlSyntaxValidator.isValidForExecuteQuery(sql))
-            throw new SQLException("not a valid sql for executeQuery: " + sql);
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_FOR_EXECUTE_QUERY, "not a valid sql for executeQuery: " + sql);
 
         final String url = "http://" + conn.getHost() + ":" + conn.getPort() + "/rest/sql";
         if (SqlSyntaxValidator.isDatabaseUnspecifiedQuery(sql)) {
@@ -73,7 +75,7 @@ public class RestfulStatement extends AbstractStatement {
         }
 
         if (this.database == null || this.database.isEmpty())
-            throw new SQLException("Database not specified or available");
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_DATABASE_NOT_SPECIFIED_OR_AVAILABLE);
         HttpClientPoolUtil.execute(url, "use " + this.database);
         return executeOneQuery(url, sql);
     }
@@ -81,9 +83,9 @@ public class RestfulStatement extends AbstractStatement {
     @Override
     public int executeUpdate(String sql) throws SQLException {
         if (isClosed())
-            throw new SQLException("statement already closed");
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_STATEMENT_CLOSED);
         if (!SqlSyntaxValidator.isValidForExecuteUpdate(sql))
-            throw new SQLException("not a valid sql for executeUpdate: " + sql);
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_FOR_EXECUTE_UPDATE, "not a valid sql for executeUpdate: " + sql);
 
         final String url = "http://" + conn.getHost() + ":" + conn.getPort() + "/rest/sql";
         if (SqlSyntaxValidator.isDatabaseUnspecifiedUpdate(sql)) {
@@ -91,7 +93,8 @@ public class RestfulStatement extends AbstractStatement {
         }
 
         if (this.database == null || this.database.isEmpty())
-            throw new SQLException("Database not specified or available");
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_DATABASE_NOT_SPECIFIED_OR_AVAILABLE);
+
         HttpClientPoolUtil.execute(url, "use " + this.database);
         return executeOneUpdate(url, sql);
     }
@@ -107,9 +110,9 @@ public class RestfulStatement extends AbstractStatement {
     @Override
     public boolean execute(String sql) throws SQLException {
         if (isClosed())
-            throw new SQLException("Invalid method call on a closed statement.");
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_STATEMENT_CLOSED);
         if (!SqlSyntaxValidator.isValidForExecute(sql))
-            throw new SQLException("not a valid sql for execute: " + sql);
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_FOR_EXECUTE, "not a valid sql for execute: " + sql);
 
         //如果执行了use操作应该将当前Statement的catalog设置为新的database
         final String url = "http://" + conn.getHost() + ":" + conn.getPort() + "/rest/sql";
@@ -134,7 +137,7 @@ public class RestfulStatement extends AbstractStatement {
 
     private ResultSet executeOneQuery(String url, String sql) throws SQLException {
         if (!SqlSyntaxValidator.isValidForExecuteQuery(sql))
-            throw new SQLException("not a select sql for executeQuery: " + sql);
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_FOR_EXECUTE_QUERY, "not a valid sql for executeQuery: " + sql);
 
         // row data
         String result = HttpClientPoolUtil.execute(url, sql);
@@ -165,7 +168,7 @@ public class RestfulStatement extends AbstractStatement {
 
     private int executeOneUpdate(String url, String sql) throws SQLException {
         if (!SqlSyntaxValidator.isValidForExecuteUpdate(sql))
-            throw new SQLException("not a valid sql for executeUpdate: " + sql);
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_FOR_EXECUTE_UPDATE, "not a valid sql for executeUpdate: " + sql);
 
         String result = HttpClientPoolUtil.execute(url, sql);
         JSONObject jsonObject = JSON.parseObject(result);
@@ -186,16 +189,16 @@ public class RestfulStatement extends AbstractStatement {
 
     @Override
     public int getUpdateCount() throws SQLException {
-        if (isClosed()) {
-            throw new SQLException("Invalid method call on a closed statement.");
-        }
+        if (isClosed())
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_STATEMENT_CLOSED);
+
         return this.affectedRows;
     }
 
     @Override
     public void addBatch(String sql) throws SQLException {
         if (isClosed())
-            throw new SQLException(TSDBConstants.STATEMENT_CLOSED);
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_STATEMENT_CLOSED);
         //TODO:
     }
 
@@ -213,7 +216,7 @@ public class RestfulStatement extends AbstractStatement {
     @Override
     public Connection getConnection() throws SQLException {
         if (isClosed())
-            throw new SQLException(TSDBConstants.STATEMENT_CLOSED);
+            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_STATEMENT_CLOSED);
         return this.conn;
     }
 
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBConnectionTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBConnectionTest.java
index 289e6b83ad..0a4ecb739c 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBConnectionTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBConnectionTest.java
@@ -47,7 +47,7 @@ public class TSDBConnectionTest {
             }
             Assert.assertNotNull(rs);
             subscribe.close(false);
-        } catch (SQLException | OperationsException e) {
+        } catch (SQLException e) {
             e.printStackTrace();
         }
 
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/ImportTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ImportTest.java
similarity index 98%
rename from src/connector/jdbc/src/test/java/com/taosdata/jdbc/ImportTest.java
rename to src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ImportTest.java
index 9d1884e6c2..b5f5c7b589 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/ImportTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ImportTest.java
@@ -1,5 +1,6 @@
-package com.taosdata.jdbc;
+package com.taosdata.jdbc.cases;
 
+import com.taosdata.jdbc.TSDBDriver;
 import org.junit.*;
 import org.junit.runners.MethodSorters;
 
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/QueryDataTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/QueryDataTest.java
similarity index 96%
rename from src/connector/jdbc/src/test/java/com/taosdata/jdbc/QueryDataTest.java
rename to src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/QueryDataTest.java
index 37fbc28487..d0ba113b7a 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/QueryDataTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/QueryDataTest.java
@@ -1,5 +1,6 @@
-package com.taosdata.jdbc;
+package com.taosdata.jdbc.cases;
 
+import com.taosdata.jdbc.TSDBDriver;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/SelectTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/SelectTest.java
similarity index 97%
rename from src/connector/jdbc/src/test/java/com/taosdata/jdbc/SelectTest.java
rename to src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/SelectTest.java
index 7db37beaf4..38c8cbb98c 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/SelectTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/SelectTest.java
@@ -1,5 +1,6 @@
-package com.taosdata.jdbc;
+package com.taosdata.jdbc.cases;
 
+import com.taosdata.jdbc.TSDBDriver;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/StableTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/StableTest.java
similarity index 98%
rename from src/connector/jdbc/src/test/java/com/taosdata/jdbc/StableTest.java
rename to src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/StableTest.java
index 0a1c548baa..4575cb73a0 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/StableTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/StableTest.java
@@ -1,5 +1,6 @@
-package com.taosdata.jdbc;
+package com.taosdata.jdbc.cases;
 
+import com.taosdata.jdbc.TSDBDriver;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.FixMethodOrder;