improved mysql exception sorter.

src/test/java/com/alibaba/druid/bvt/pool/vendor/MySqlExceptionSorterTest_1.java

@@ -0,0 +1,24 @@
+package com.alibaba.druid.bvt.pool.vendor;
+
+import com.alibaba.druid.pool.vendor.MySqlExceptionSorter;
+import com.mysql.jdbc.CommunicationsException;
+import junit.framework.TestCase;
+
+import java.sql.SQLException;
+
+/**
+ * Created by wenshao on 18/07/2017.
+ */
+public class MySqlExceptionSorterTest_1 extends TestCase {
+    public void test_0() throws Exception {
+        MySqlExceptionSorter sorter = new MySqlExceptionSorter();
+
+        SQLException rootException = new SQLException(
+                new SQLException("Could not retrieve transation read-only status server",
+                        new CommunicationsException(null, 0, 0, null)
+                )
+        );
+
+        assertTrue(sorter.isExceptionFatal(rootException));
+    }
+}

src/test/java/com/alibaba/druid/bvt/pool/vendor/MySqlExceptionSorterTest_2.java

@@ -0,0 +1,25 @@
+package com.alibaba.druid.bvt.pool.vendor;
+
+import com.alibaba.druid.pool.vendor.MySqlExceptionSorter;
+import com.mysql.jdbc.CommunicationsException;
+import junit.framework.TestCase;
+
+import java.net.SocketTimeoutException;
+import java.sql.SQLException;
+
+/**
+ * Created by wenshao on 18/07/2017.
+ */
+public class MySqlExceptionSorterTest_2 extends TestCase {
+    public void test_0() throws Exception {
+        MySqlExceptionSorter sorter = new MySqlExceptionSorter();
+
+        SQLException rootException = new SQLException(
+                new SQLException("Could not retrieve transation read-only status server",
+                        new SocketTimeoutException()
+                )
+        );
+
+        assertTrue(sorter.isExceptionFatal(rootException));
+    }
+}