[Fix-5808][Server] When we try to transfer data using datax between ...

[Fix-5808][Server]  When we try to transfer data using datax between  different types of data sources, the worker will exit with ClassCastException (#5809)

* bug fix

* fix bug

* simplify the code format

* add a new parameter to make it easier to understand.

dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/datax/DataxTask.java

@@ -252,7 +252,7 @@ public class DataxTask extends AbstractTask {
         }
 
         ArrayNode urlArr = readerConn.putArray("jdbcUrl");
-        urlArr.add(DatasourceUtil.getJdbcUrl(DbType.valueOf(dataXParameters.getDtType()), dataSourceCfg));
+        urlArr.add(DatasourceUtil.getJdbcUrl(DbType.valueOf(dataXParameters.getDsType()), dataSourceCfg));
 
         readerConnArr.add(readerConn);
 
@@ -270,7 +270,7 @@ public class DataxTask extends AbstractTask {
         ArrayNode tableArr = writerConn.putArray("table");
         tableArr.add(dataXParameters.getTargetTable());
 
-        writerConn.put("jdbcUrl", DatasourceUtil.getJdbcUrl(DbType.valueOf(dataXParameters.getDsType()), dataTargetCfg));
+        writerConn.put("jdbcUrl", DatasourceUtil.getJdbcUrl(DbType.valueOf(dataXParameters.getDtType()), dataTargetCfg));
         writerConnArr.add(writerConn);
 
         ObjectNode writerParam = JSONUtils.createObjectNode();
@@ -437,31 +437,31 @@ public class DataxTask extends AbstractTask {
     }
 
     public String loadJvmEnv(DataxParameters dataXParameters) {
-        int xms = dataXParameters.getXms() < 1 ? 1 : dataXParameters.getXms();
-        int xmx = dataXParameters.getXmx() < 1 ? 1 : dataXParameters.getXmx();
+        int xms = Math.max(dataXParameters.getXms(), 1);
+        int xmx = Math.max(dataXParameters.getXmx(), 1);
         return String.format(JVM_PARAM, xms, xmx);
     }
 
     /**
      * parsing synchronized column names in SQL statements
      *
-     * @param dsType the database type of the data source
-     * @param dtType the database type of the data target
+     * @param sourceType the database type of the data source
+     * @param targetType the database type of the data target
      * @param dataSourceCfg the database connection parameters of the data source
      * @param sql sql for data synchronization
      * @return Keyword converted column names
      */
-    private String[] parsingSqlColumnNames(DbType dsType, DbType dtType, BaseConnectionParam dataSourceCfg, String sql) {
-        String[] columnNames = tryGrammaticalAnalysisSqlColumnNames(dsType, sql);
+    private String[] parsingSqlColumnNames(DbType sourceType, DbType targetType, BaseConnectionParam dataSourceCfg, String sql) {
+        String[] columnNames = tryGrammaticalAnalysisSqlColumnNames(sourceType, sql);
 
         if (columnNames == null || columnNames.length == 0) {
             logger.info("try to execute sql analysis query column name");
-            columnNames = tryExecuteSqlResolveColumnNames(dataSourceCfg, sql);
+            columnNames = tryExecuteSqlResolveColumnNames(sourceType, dataSourceCfg, sql);
         }
 
         notNull(columnNames, String.format("parsing sql columns failed : %s", sql));
 
-        return DataxUtils.convertKeywordsColumns(dtType, columnNames);
+        return DataxUtils.convertKeywordsColumns(targetType, columnNames);
     }
 
     /**
@@ -542,13 +542,13 @@ public class DataxTask extends AbstractTask {
      * @param sql sql for data synchronization
      * @return column name array
      */
-    public String[] tryExecuteSqlResolveColumnNames(BaseConnectionParam baseDataSource, String sql) {
+    public String[] tryExecuteSqlResolveColumnNames(DbType sourceType, BaseConnectionParam baseDataSource, String sql) {
         String[] columnNames;
         sql = String.format("SELECT t.* FROM ( %s ) t WHERE 0 = 1", sql);
         sql = sql.replace(";", "");
 
         try (
-                Connection connection = DatasourceUtil.getConnection(DbType.valueOf(dataXParameters.getDtType()), baseDataSource);
+                Connection connection = DatasourceUtil.getConnection(sourceType, baseDataSource);
                 PreparedStatement stmt = connection.prepareStatement(sql);
                 ResultSet resultSet = stmt.executeQuery()) {