[TD-1590]<test>: a test case for JDBC failover

src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/FailOverTest.java

+package com.taosdata.jdbc.cases;
+
+import com.taosdata.jdbc.lib.TSDBCommon;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+public class FailOverTest {
+
+    private Connection conn;
+    private static final String host = "localhost";
+
+    @Before
+    public void before() {
+        try {
+            Class.forName("com.taosdata.jdbc.TSDBDriver");
+            conn = TSDBCommon.getConn(host);
+            TSDBCommon.createDatabase(conn, "failover_test");
+        } catch (ClassNotFoundException | SQLException e) {
+            e.printStackTrace();
+        }
+    }
+
+    @Test
+    public void testFailOver() {
+        try (Statement stmt = conn.createStatement()) {
+            ResultSet resultSet = stmt.executeQuery("select server_status()");
+            while (true) {
+                resultSet.next();
+                int status = resultSet.getInt("server_status()");
+                System.out.println(">>>>>>>>> status : " + status);
+            }
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+
+    }
+
+    @After
+    public void after() {
+        try {
+            if (conn != null)
+                conn.close();
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+    }
+}