refactor

src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java

@@ -493,6 +493,10 @@ public abstract class DruidAbstractDataSource extends WrapperAdapter implements
     public String getDbType() {
         return dbType;
     }
+    
+    public void setDbType(String dbType) {
+        this.dbType = dbType;
+    }
 
     public void addConnectionProperty(String name, String value) {
         if (inited) {

src/main/java/com/alibaba/druid/pool/DruidDataSource.java

@@ -291,8 +291,10 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
                 }
             }
 
-            this.dbType = JdbcUtils.getDbType(jdbcUrl, driverClass.getClass().getName());
-
+            if (this.dbType == null || this.dbType.length() == 0) {
+                this.dbType = JdbcUtils.getDbType(jdbcUrl, driverClass.getClass().getName());
+            }
+            
             if ("oracle".equals(this.dbType)) {
                 isOracle = true;
 

src/main/java/com/alibaba/druid/wall/WallFilter.java

@@ -40,30 +40,28 @@ public class WallFilter extends FilterAdapter implements WallFilterMBean {
     public void init(DataSourceProxy dataSource) {
         this.dataSource = dataSource;
 
-        String dbType = this.dbType;
-
         if (this.dbType == null || this.dbType.trim().length() == 0) {
             this.dbType = dataSource.getDbType();
         }
 
         if (JdbcUtils.MYSQL.equals(dbType)) {
-            provider = new MySqlWallProvider(config);
-
             if (config == null) {
                 config = new WallConfig(MySqlWallProvider.DEFAULT_CONFIG_DIR);
             }
+            
+            provider = new MySqlWallProvider(config);
         } else if (JdbcUtils.ORACLE.equals(dbType)) {
-            provider = new OracleWallProvider(config);
-
             if (config == null) {
                 config = new WallConfig(OracleWallProvider.DEFAULT_CONFIG_DIR);
             }
+            
+            provider = new OracleWallProvider(config);
         } else if (JdbcUtils.SQL_SERVER.equals(dbType)) {
-            provider = new SQLServerProvider(config);
-
             if (config == null) {
                 config = new WallConfig(SQLServerProvider.DEFAULT_CONFIG_DIR);
             }
+            
+            provider = new SQLServerProvider(config);
         } else {
             throw new IllegalStateException("dbType not support : " + dbType);
         }