源代码：

 package hadoop.mysql;

 import java.io.IOException;

 import java.io.InputStream;

 import java.nio.file.Files;

 import java.nio.file.Paths;

 import java.sql.Connection;

 import java.sql.DriverManager;

 import java.sql.ResultSet;

 import java.sql.SQLException;

 import java.sql.Statement;

 import java.util.Properties;

 /**

  *

 * @ClassName: Sql

 * @Description: This program tests that the database and the JDBC driver are correctly configured

 * @author ***

 * @date 2017-9-4 下午11:27:22

 *

  */

 public class Sql {

     /**

      *

     * @Title: getConnection

     * @Description: Gets a connection from the properties specified in the file database,properties

     * @throws IOException

     * @throws SQLException

     * @return Connection

      */

     public static Connection getConnection ( ) throws IOException, SQLException

     {

         //创建一个Properties，并加载database.properties

         Properties props = new Properties() ;

         try ( InputStream in = Files.newInputStream(Paths.get("H://java//com.autwit.www//src//main//resources//database.properties")))

                 {

                     props.load( in ) ;

                 }

         //驱动程序名

         String drivers = props.getProperty( "jdbc.drivers" ) ;

         if(drivers != null ) System.setProperty( "jdbc.drivers", drivers ) ;

         //URL指向要访问的数据库名wuwei

         String url = props.getProperty( "jdbc.url" ) ;

         //数据库用户名

         String username = props.getProperty( "jdbc.username" ) ;

         //密码

         String password = props.getProperty( "jdbc.password" ) ;

         return DriverManager.getConnection( url, username, password ) ;

     }

     /**

      *

     * @Title: runTest

     * @Description: create a connect with MySql,Then executing C(create)R(read)U(Update)D(delete)

     *

     * @throws SQLException

     * @throws IOException

     * @return void

      */

     public static void runTest() throws SQLException, IOException

     {

         //声明Connection对象

         try( Connection con = getConnection() )

         {

             //创建statement类对象，用来执行SQL语句

             Statement stat = con.createStatement( ) ;

             stat.executeUpdate(" create table Greeting ( Message Char(20) )") ;

             stat.executeUpdate( "Insert into Greeting values ('Hello world!' )") ;

             //ResultSet类，用来存放获取的结果集！！

             try (ResultSet rs = stat.executeQuery("select * from Greeting"))

             {

                 /*

                 Notice :即使你十分确定能搜出记录，也不可以在没有rs.next()之前直接对rs进行取值。

                 这涉及到rs对象的存储方法。里面说白了就是指针。没next，指针根本没指向对应记录

                 */

                 String message = "";

                 if(rs.next()){//或者while(rs.next())

                    message = rs.getString("Message");

                    if(message == null){

                        message = "";

                    }

                    System.out.println(message);

                 }

             }

             stat.executeUpdate("drop table Greeting") ;

         }

     }

     public static void main(String[] args) throws SQLException, IOException {

         runTest( ) ;

     }

 }