JDBC编程的回顾

1、准备数据

-- 创建数据库
CREATE DATABASE mybatis;

-- 使用数据库
USE mybatis;

-- 删除表
DROP TABLE IF EXISTS user;

-- 创建表
CREATE TABLE `user` (
  `id` int(11) NOT NULL auto_increment,
  `username` varchar(32) NOT NULL COMMENT '用户名称',
  `birthday` datetime default NULL COMMENT '生日',
  `sex` char(1) default NULL COMMENT '性别',
  `address` varchar(256) default NULL COMMENT '地址',
  PRIMARY KEY  (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- 插入数据
insert  into `user`(`id`,`username`,`birthday`,`sex`,`address`) values (41,'张三','2019-03-27 18:47:08','男','北京');
insert  into `user`(`id`,`username`,`birthday`,`sex`,`address`) values (42,'李四','2019-03-27 18:47:08','男','上海');
insert  into `user`(`id`,`username`,`birthday`,`sex`,`address`) values (43,'王五','2019-03-27 18:47:08','男','广州');

2、搭建maven工程

File -> New -> Module

Maven -> Module SDK -> Next

Finish

导入坐标

3、JDBC编程

import java.sql.*;

public class TestJdbc {
    public static void main(String args[]) {
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;
        try {
            //1. 加载驱动
            Class.forName("com.mysql.jdbc.Driver");
            //2. 获取连接
            String url = "jdbc:mysql://localhost:3306/mybatis";
            String username = "root";
            String password = "root";
            connection = DriverManager.getConnection(url, username, password);
            //3. 获取预处理对象
            String sql = "SELECT * FROM user WHERE id = ?";
            preparedStatement = connection.prepareStatement(sql);
            // 设置参数
            preparedStatement.setInt(1,41);
            // 执行查询
            resultSet = preparedStatement.executeQuery();
            // 处理结果集
            while (resultSet.next()) {
                System.out.println(resultSet.getString("username"));
                System.out.println(resultSet.getDate("birthday"));
                System.out.println(resultSet.getString("sex"));
                System.out.println(resultSet.getString("address"));
            }
        }catch (Exception ex) {
            ex.printStackTrace();
        }finally {
            try {
                // 关闭连接，释放资源
                if (resultSet != null) {
                    resultSet.close();
                }
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            }catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
    }
}

4、JDBC变成缺点分析