[issue_1187][plugin] fix mysql download (#1187)

Author: Sunny

taier-datasource/taier-datasource-plugin/taier-datasource-plugin-mysql5/src/main/java/com/dtstack/taier/datasource/plugin/mysql5/MysqlDownloader.java

@@ -88,12 +88,15 @@ public boolean configure() throws Exception {
         String countSQL = String.format("SELECT COUNT(*) FROM (%s) temp", sql);
         String showColumns = String.format("SELECT * FROM (%s) t limit 1", sql);
 
-        try (ResultSet totalResultSet = statement.executeQuery(countSQL);
-             ResultSet columnsResultSet = statement.executeQuery(showColumns)) {
+        ResultSet totalResultSet = null;
+        ResultSet columnsResultSet = null;
+        try {
+            totalResultSet = statement.executeQuery(countSQL);
             while (totalResultSet.next()) {
                 //获取总行数
                 totalLine = totalResultSet.getInt(1);
             }
+            columnsResultSet = statement.executeQuery(showColumns);
             //获取列信息
             columnNames = new ArrayList<>();
             columnCount = columnsResultSet.getMetaData().getColumnCount();
@@ -108,6 +111,9 @@ public boolean configure() throws Exception {
             pageAll = (int) Math.ceil(totalLine / (double) pageSize);
         } catch (Exception e) {
             throw new SourceException("build Mysql downloader message exception : " + e.getMessage(), e);
+        } finally {
+            DBUtil.closeDBResources(totalResultSet, null, null);
+            DBUtil.closeDBResources(columnsResultSet, null, null);
         }
         return true;
     }