jdbc连接mysql数据库注意事项

1.导入mysql驱动  http://blog.csdn.net/a153375250/article/details/50851049

2.开放机器访问权限

mysql>GRANT ALL PRIVILEGES ON *.* TO 'root'@'%'IDENTIFIED BY '123456' WITH GRANT OPTION; 
 
mysql>FLUSH PRIVILEGES 

3.关闭防火墙 

[root@localhost ~]# systemctl stop firewalld

代码

import java.sql.*;


public class TestDemo {

    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://172.16.2.116:3306/RUNOOB";
    static final String USER = "root";
    static final String PASS = "520224";

    public static void main(String[] args) throws  Exception{

        try{

            //加载mysql驱动
            Class.forName("JDBC_DRIVER");
            //建立连接
            Connection conn = DriverManager.getConnection(DB_URL,USER,PASS);
            //创建语句实例
            Statement stmt = conn.createStatement();

            String sql= "SELECT id, name, url FROM websites";
            //执行查询
            ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                String url = rs.getString("url");
                System.out.println(id+","+name+","+ url);
            }

            rs.close();
            stmt.close();
            conn.close();
        }catch(SQLException se){
            // 处理 JDBC 错误
            se.printStackTrace();
        }catch(Exception e){
            // 处理 Class.forName 错误
            e.printStackTrace();
        }

    }
}