bug fixed for dbType compare, fix #4005

Author: wenshao

src/main/java/com/alibaba/druid/DbType.java

@@ -99,4 +99,8 @@ public static DbType of(String name) {
             return null;
         }
     }
+
+    public final boolean equals(String other) {
+        return this == of(other);
+    }
 }

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

@@ -867,7 +867,7 @@ public int getValidationQueryTimeout() {
     }
 
     public void setValidationQueryTimeout(int validationQueryTimeout) {
-        if (validationQueryTimeout < 0 && JdbcConstants.SQL_SERVER.equals(dbTypeName)) {
+        if (validationQueryTimeout < 0 && DbType.of(dbTypeName) == DbType.sqlserver) {
             LOG.error("validationQueryTimeout should be >= 0");
         }
         this.validationQueryTimeout = validationQueryTimeout;

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

@@ -29,6 +29,7 @@
 import javax.sql.ConnectionEventListener;
 import javax.sql.StatementEventListener;
 
+import com.alibaba.druid.DbType;
 import com.alibaba.druid.pool.DruidAbstractDataSource.PhysicalConnectionInfo;
 import com.alibaba.druid.proxy.jdbc.WrapperProxy;
 import com.alibaba.druid.support.logging.Log;
@@ -112,10 +113,11 @@ public DruidConnectionHolder(DruidAbstractDataSource dataSource, Connection conn
 
         {
             boolean initUnderlyHoldability = !holdabilityUnsupported;
-            if (JdbcConstants.SYBASE.equals(dataSource.dbTypeName) //
-                || JdbcConstants.DB2.equals(dataSource.dbTypeName) //
-                || JdbcConstants.HIVE.equals(dataSource.dbTypeName) //
-                || JdbcConstants.ODPS.equals(dataSource.dbTypeName) //
+            DbType dbType = DbType.of(dataSource.dbTypeName);
+            if (dbType == DbType.sybase //
+                    || dbType == DbType.db2 //
+                    || dbType == DbType.hive //
+                    || dbType == DbType.odps //
             ) {
                 initUnderlyHoldability = false;
             }