replace strings with constants already exist. (#1825)

dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/job/db/ClickHouseDataSource.java

@@ -16,6 +16,7 @@
  */
 package org.apache.dolphinscheduler.common.job.db;
 
+import org.apache.dolphinscheduler.common.Constants;
 import org.apache.dolphinscheduler.common.utils.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -58,7 +59,7 @@ public class ClickHouseDataSource extends BaseDataSource {
     public void isConnectable() throws Exception {
         Connection con = null;
         try {
-            Class.forName("ru.yandex.clickhouse.ClickHouseDriver");
+            Class.forName(Constants.COM_CLICKHOUSE_JDBC_DRIVER);
             con = DriverManager.getConnection(getJdbcUrl(), getUser(), getPassword());
         } finally {
             if (con != null) {

dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/job/db/HiveDataSource.java

@@ -16,6 +16,7 @@
  */
 package org.apache.dolphinscheduler.common.job.db;
 
+import org.apache.dolphinscheduler.common.Constants;
 import org.apache.dolphinscheduler.common.utils.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -61,7 +62,7 @@ public class HiveDataSource extends BaseDataSource {
   public void isConnectable() throws Exception {
     Connection con = null;
     try {
-      Class.forName("org.apache.hive.jdbc.HiveDriver");
+      Class.forName(Constants.ORG_APACHE_HIVE_JDBC_HIVE_DRIVER);
       con = DriverManager.getConnection(getJdbcUrl(), getUser(), "");
     } finally {
       if (con != null) {

dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/job/db/MySQLDataSource.java

@@ -16,6 +16,7 @@
  */
 package org.apache.dolphinscheduler.common.job.db;
 
+import org.apache.dolphinscheduler.common.Constants;
 import org.apache.dolphinscheduler.common.utils.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -56,7 +57,7 @@ public class MySQLDataSource extends BaseDataSource {
   public void isConnectable() throws Exception {
     Connection con = null;
     try {
-      Class.forName("com.mysql.jdbc.Driver");
+      Class.forName(Constants.COM_MYSQL_JDBC_DRIVER);
       con = DriverManager.getConnection(getJdbcUrl(), getUser(), getPassword());
     } finally {
       if (con != null) {

dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/job/db/OracleDataSource.java

@@ -16,6 +16,7 @@
  */
 package org.apache.dolphinscheduler.common.job.db;
 
+import org.apache.dolphinscheduler.common.Constants;
 import org.apache.dolphinscheduler.common.utils.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -58,7 +59,7 @@ public class OracleDataSource extends BaseDataSource {
     public void isConnectable() throws Exception {
         Connection con = null;
         try {
-            Class.forName("oracle.jdbc.driver.OracleDriver");
+            Class.forName(Constants.COM_ORACLE_JDBC_DRIVER);
             con = DriverManager.getConnection(getJdbcUrl(), getUser(), getPassword());
         } finally {
             if (con != null) {

dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/job/db/PostgreDataSource.java

@@ -16,6 +16,7 @@
  */
 package org.apache.dolphinscheduler.common.job.db;
 
+import org.apache.dolphinscheduler.common.Constants;
 import org.apache.dolphinscheduler.common.utils.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -60,7 +61,7 @@ public class PostgreDataSource extends BaseDataSource {
   public void isConnectable() throws Exception {
     Connection con = null;
     try {
-      Class.forName("org.postgresql.Driver");
+      Class.forName(Constants.ORG_POSTGRESQL_DRIVER);
       con = DriverManager.getConnection(getJdbcUrl(), getUser(), getPassword());
     } finally {
       if (con != null) {

dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/job/db/SQLServerDataSource.java

@@ -16,6 +16,7 @@
  */
 package org.apache.dolphinscheduler.common.job.db;
 
+import org.apache.dolphinscheduler.common.Constants;
 import org.apache.dolphinscheduler.common.utils.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -54,7 +55,7 @@ public class SQLServerDataSource extends BaseDataSource {
     public void isConnectable() throws Exception {
         Connection con = null;
         try {
-            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
+            Class.forName(Constants.COM_SQLSERVER_JDBC_DRIVER);
             con = DriverManager.getConnection(getJdbcUrl(), getUser(), getPassword());
         } finally {
             if (con != null) {

dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/job/db/SparkDataSource.java

@@ -16,6 +16,7 @@
  */
 package org.apache.dolphinscheduler.common.job.db;
 
+import org.apache.dolphinscheduler.common.Constants;
 import org.apache.dolphinscheduler.common.utils.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -63,7 +64,7 @@ public class SparkDataSource extends BaseDataSource {
   public void isConnectable() throws Exception {
     Connection con = null;
     try {
-      Class.forName("org.apache.hive.jdbc.HiveDriver");
+      Class.forName(Constants.ORG_APACHE_HIVE_JDBC_HIVE_DRIVER);
       con = DriverManager.getConnection(getJdbcUrl(), getUser(), "");
     } finally {
       if (con != null) {