diff --git a/dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/sql/SqlTask.java b/dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/sql/SqlTask.java
index a6eb26668e..56177e166f 100644
--- a/dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/sql/SqlTask.java
+++ b/dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/sql/SqlTask.java
@@ -18,7 +18,6 @@ package org.apache.dolphinscheduler.server.worker.task.sql;
 
 import com.alibaba.fastjson.JSONArray;
 import com.alibaba.fastjson.JSONObject;
-import com.alibaba.fastjson.serializer.SerializerFeature;
 import org.apache.commons.lang.StringUtils;
 import org.apache.dolphinscheduler.alert.utils.MailUtils;
 import org.apache.dolphinscheduler.common.Constants;
@@ -86,7 +85,7 @@ public class SqlTask extends AbstractTask {
         this.taskExecutionContext = taskExecutionContext;
 
         logger.info("sql task params {}", taskExecutionContext.getTaskParams());
-        this.sqlParameters = JSONObject.parseObject(taskExecutionContext.getTaskParams(), SqlParameters.class);
+        this.sqlParameters = JSONUtils.parseObject(taskExecutionContext.getTaskParams(), SqlParameters.class);
 
         if (!sqlParameters.checkParameters()) {
             throw new RuntimeException("sql task params is not valid");
@@ -148,8 +147,8 @@ public class SqlTask extends AbstractTask {
     }
 
     /**
-     *  ready to execute SQL and parameter entity Map
-     * @return
+     * ready to execute SQL and parameter entity Map
+     * @return SqlBinds
      */
     private SqlBinds getSqlAndSqlParamsMap(String sql) {
         Map<Integer,Property> sqlParamsMap =  new HashMap<>();
@@ -176,6 +175,7 @@ public class SqlTask extends AbstractTask {
             logger.info("SQL title : {}",title);
             sqlParameters.setTitle(title);
         }
+        
         //new
         //replace variable TIME with $[YYYYmmddd...] in sql when history run job and batch complement job
         sql = ParameterUtils.replaceScheduleTime(sql, taskExecutionContext.getScheduleTime());
@@ -267,18 +267,12 @@ public class SqlTask extends AbstractTask {
             resultJSONArray.add(mapOfColValues);
             rowCount++;
         }
-        logger.debug("execute sql : {}", JSONObject.toJSONString(resultJSONArray, SerializerFeature.WriteMapNullValue));
-
-        // if there is a result set
-        if (!resultJSONArray.isEmpty() ) {
-            if (StringUtils.isNotEmpty(sqlParameters.getTitle())) {
-                sendAttachment(sqlParameters.getTitle(),
-                        JSONObject.toJSONString(resultJSONArray, SerializerFeature.WriteMapNullValue));
-            }else{
-                sendAttachment(taskExecutionContext.getTaskName() + " query resultsets ",
-                        JSONObject.toJSONString(resultJSONArray, SerializerFeature.WriteMapNullValue));
-            }
-        }
+        String result = JSONUtils.toJsonString(resultJSONArray);
+        logger.debug("execute sql : {}", result);
+
+        sendAttachment(StringUtils.isNotEmpty(sqlParameters.getTitle()) ?
+                        sqlParameters.getTitle(): taskExecutionContext.getTaskName() + " query result sets",
+                JSONUtils.toJsonString(resultJSONArray));
     }
 
     /**
@@ -299,7 +293,7 @@ public class SqlTask extends AbstractTask {
     }
 
     /**
-     * post psql
+     * post sql
      *
      * @param connection connection
      * @param postStatementsBinds postStatementsBinds
@@ -330,11 +324,12 @@ public class SqlTask extends AbstractTask {
             }
         }
     }
+    
     /**
      * create connection
      *
      * @return connection
-     * @throws Exception
+     * @throws Exception Exception
      */
     private Connection createConnection() throws Exception{
         // if hive , load connection params if exists
@@ -370,17 +365,17 @@ public class SqlTask extends AbstractTask {
                        Connection connection){
         if (resultSet != null){
             try {
-                connection.close();
+                resultSet.close();
             } catch (SQLException e) {
-
+                logger.error("close result set error : {}",e.getMessage(),e);
             }
         }
 
         if (pstmt != null){
             try {
-                connection.close();
+                pstmt.close();
             } catch (SQLException e) {
-
+                logger.error("close prepared statement error : {}",e.getMessage(),e);
             }
         }
 
@@ -388,17 +383,17 @@ public class SqlTask extends AbstractTask {
             try {
                 connection.close();
             } catch (SQLException e) {
-
+                logger.error("close connection error : {}",e.getMessage(),e);
             }
         }
     }
 
     /**
      * preparedStatement bind
-     * @param connection
-     * @param sqlBinds
-     * @return
-     * @throws Exception
+     * @param connection connection
+     * @param sqlBinds  sqlBinds
+     * @return PreparedStatement
+     * @throws Exception Exception
      */
     private PreparedStatement prepareStatementAndBind(Connection connection, SqlBinds sqlBinds) throws Exception {
         // is the timeout set
@@ -429,34 +424,34 @@ public class SqlTask extends AbstractTask {
         List<User> users = alertDao.queryUserByAlertGroupId(taskExecutionContext.getSqlTaskExecutionContext().getWarningGroupId());
 
         // receiving group list
-        List<String> receviersList = new ArrayList<>();
+        List<String> receiversList = new ArrayList<>();
         for(User user:users){
-            receviersList.add(user.getEmail().trim());
+            receiversList.add(user.getEmail().trim());
         }
         // custom receiver
         String receivers = sqlParameters.getReceivers();
         if (StringUtils.isNotEmpty(receivers)){
             String[] splits = receivers.split(COMMA);
             for (String receiver : splits){
-                receviersList.add(receiver.trim());
+                receiversList.add(receiver.trim());
             }
         }
 
         // copy list
-        List<String> receviersCcList = new ArrayList<>();
+        List<String> receiversCcList = new ArrayList<>();
         // Custom Copier
         String receiversCc = sqlParameters.getReceiversCc();
         if (StringUtils.isNotEmpty(receiversCc)){
             String[] splits = receiversCc.split(COMMA);
             for (String receiverCc : splits){
-                receviersCcList.add(receiverCc.trim());
+                receiversCcList.add(receiverCc.trim());
             }
         }
 
         String showTypeName = sqlParameters.getShowType().replace(COMMA,"").trim();
         if(EnumUtils.isValidEnum(ShowType.class,showTypeName)){
-            Map<String, Object> mailResult = MailUtils.sendMails(receviersList,
-                    receviersCcList, title, content, ShowType.valueOf(showTypeName).getDescp());
+            Map<String, Object> mailResult = MailUtils.sendMails(receiversList,
+                    receiversCcList, title, content, ShowType.valueOf(showTypeName).getDescp());
             if(!(boolean) mailResult.get(STATUS)){
                 throw new RuntimeException("send mail failed!");
             }