Mybatis入门：(3)数据的增删改查

接上一节：Mybatis入门：（2）接口方式编程

一、工程结构：

二、变动的文件

1、User.xml

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <!-- 此时这个namespace的值不能随便写，一定要是IUserDao的全路径 --> <mapper namespace="com.linbilin.mybatis.dao.IUserDao"> <select id="getUserByID" parameterType="int" resultType="User"> select * from `user` where id = #{id} </select> <resultMap type="User" id="userListResult"> <id column="id" property="id"/> <result column="name" property="name"/> <result column="dept" property="dept"/> <result column="website" property="website"/> <result column="phone" property="phone"/> </resultMap> <select id="queryUsers" resultMap="userListResult"> select * from user </select> <!-- seGeneratedKeys设置 为"true"表示要myBatis获取由数据库自动生成的主键, keyProperty="id"指定把获取到的主键值注入到User的id属性。 如果要用这两个属性的话，建表的时候需要把id字段设置为自增 --> <insert id="addUser" parameterType="User" useGeneratedKeys="true" keyProperty="id"> INSERT INTO user(`name`,`dept`,`website`,`phone`) VALUES (#{name},#{dept},#{website},#{phone}) </insert> <update id="updateUser" parameterType="User"> UPDATE `user` SET `name` = #{name}, `dept` = #{dept}, `website` = #{website}, `phone` = #{phone} WHERE `id` =#{id}; </update> <delete id="deleteUser" parameterType="int"> delete from user where id=#{id} </delete> </mapper>

2、MyTest

package com.linbilin.mybatis.test; import java.util.ArrayList; import java.util.List; import org.apache.ibatis.session.SqlSession; import com.linbilin.mybatis.dao.IUserDao; import com.linbilin.mybatis.models.User; import com.linbilin.mybatis.utils.MybatisUtils; public class MyTest { public static void main(String[] args) { //getUserByID(1); User user=new User(); user.setDept("销售"); user.setName("陈"); user.setPhone("17733456875"); user.setWebsite("http://www.baidu.com"); addUser(user); User user2=new User(); user2.setId(2); user2.setDept("销售"); user2.setName("陈栋"); user2.setPhone("17733456875"); user2.setWebsite("http://www.baidu.com"); //updateUser(user2); queryUsers(); //deleteUser(7); queryUsers(); } /** * 根据id查询用户 * * @param id * @return */ public static User getUserByID(int id) { SqlSession session = MybatisUtils.getSession().openSession(); User user = null; try { IUserDao userDao = session.getMapper(IUserDao.class); user = userDao.getUserByID(id); if (user != null) { String userInfo = user.toString(); System.out.println(userInfo); } } catch (Exception e) { e.printStackTrace(); } finally { session.close();// 关闭session，释放资源 } return user; } /** * 查询用户列表 * * @return */ public static List<User> queryUsers() { SqlSession session = MybatisUtils.getSession().openSession(); List<User> userList = new ArrayList<User>(); try { IUserDao userDao = session.getMapper(IUserDao.class); userList = userDao.queryUsers(); if (userList != null && !userList.isEmpty()) { for (User user : userList) { String userInfo = user.toString(); System.out.println(userInfo); } } } catch (Exception e) { e.printStackTrace(); } finally { session.close();// 关闭session，释放资源 } return userList; } /** * 添加用户 * @param user */ public static void addUser(User user){ SqlSession session = MybatisUtils.getSession().openSession(); try { IUserDao userDao = session.getMapper(IUserDao.class); userDao.addUser(user); session.commit();//提交 System.out.println("添加了"+user.getName()+"的新数据！"); } catch (Exception e) { e.printStackTrace(); } finally { session.close();// 关闭session，释放资源 } } public static void updateUser(User user){ SqlSession session = MybatisUtils.getSession().openSession(); try { IUserDao userDao = session.getMapper(IUserDao.class); userDao.updateUser(user); session.commit();//提交 System.out.println("更新了ID位"+user.getDept()+"的数据！"); } catch (Exception e) { e.printStackTrace(); } finally { session.close();// 关闭session，释放资源 } } /** * 根据ID删除数据 * @param id */ public static void deleteUser(int id){ SqlSession session = MybatisUtils.getSession().openSession(); try { IUserDao userDao = session.getMapper(IUserDao.class); userDao.deleteUser(id); session.commit();//提交 System.out.println("删除了ID为"+id+"的数据！"); } catch (Exception e) { e.printStackTrace(); } finally { session.close();// 关闭session，释放资源 } } }

3、IUserDao

package com.linbilin.mybatis.dao; import java.util.List; import com.linbilin.mybatis.models.User; public interface IUserDao { /** * 根据id查询用户 * @param id * @return */ public User getUserByID(int id); /** * 查询用户列表 * @return */ public List<User> queryUsers(); /** * 添加用户 * @param user */ public void addUser(User user); /** * 更新数据 * @param user */ public void updateUser(User user); /** * 根据id删除用户 * @param id */ public void deleteUser(int id); }

三、附件

http://pan.baidu.com/s/1slpeTqd