一、引言

二、操作

1、包结构如图

项目结构

2、mapper配置

<?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" >
<mapper namespace="com.bysoft.springmybatismanual.dao.UserDao">
    <resultMap id="BaseResultMap" type="com.bysoft.springmybatismanual.entity.User" >
        <id column="id" property="id" jdbcType="INTEGER" />
        <result column="user_name" property="userName" jdbcType="VARCHAR" />
        <result column="password" property="password" jdbcType="VARCHAR" />
        <result column="age" property="age" jdbcType="INTEGER" />
    </resultMap>

    <sql id="Base_Column_List" >
        id, user_name, password, age
    </sql>

    <select id="findAll" resultMap="BaseResultMap">
        select
        <include refid="Base_Column_List" />
        from user_t
    </select>

    <insert id="addUser" parameterType="com.bysoft.springmybatismanual.entity.User">
        insert into user_t (user_name, password, age)
        values (#{userName,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
        #{age,jdbcType=INTEGER})
    </insert>

    <update id="updateUser" parameterType="com.bysoft.springmybatismanual.entity.User" >
        update user_t
        set user_name = #{userName,jdbcType=VARCHAR},
        password = #{password,jdbcType=VARCHAR},
        age = #{age,jdbcType=INTEGER}
        where id = #{id,jdbcType=INTEGER}
    </update>

    <delete id="deleteUser" parameterType="java.lang.Integer" >
            delete from user_t
            where id = #{id,jdbcType=INTEGER}
        </delete>
</mapper>

3、User

package com.bysoft.springmybatismanual.entity;

public class User {
    private Integer id;
    private String userName;
    private String password;
    private Integer age;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName == null? null:userName.trim();
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password == null? null:password.trim() ;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

4、UserDao

@Repository
public interface UserDao {
    /**
     * 查询所有用户
     * @return
     */
    List<User> findAll();

    /**
     * 添加用户
     * @param user
     */
    void addUser(User user);

    /**
     * 跟新用户
     * @param user
     */
    void updateUser(User user);

    /**
     * 删除用户
     * @param id
     * @return
     */
    int deleteUser(Integer id);

}

5、UserService

public interface UserService {
    /**
     * 查询所有用户
     * @return
     */
    List<User> findAll();

    /**
     * 添加用户
     * @param user
     */
    void addUser(User user);

    /**
     * 跟新用户
     * @param user
     */
    void updateUser(User user);

    /**
     * 删除用户
     * @param id
     * @return
     */
    int deleteUser(Integer id);
}

6、UserServiceImpl

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserDao userDao;


    @Override
    public List<User> findAll() {
        return userDao.findAll();
    }

    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    @Override
    public void updateUser(User user) {
        userDao.updateUser(user);
    }

    @Override
    public int deleteUser(Integer id) {
        return userDao.deleteUser(id);
    }
}

7、UserController

@RestController
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping(value = "/showUser")
    public List<User> getUser(){
        return  userService.findAll();
    }

    @PostMapping(value = "/addUser")
    public void addUser(@RequestParam("username") String username,
                        @RequestParam("password") String password,
                        @RequestParam("age") Integer age){
        User user = new User();
        user.setUserName(username);
        user.setPassword(password);
        user.setAge(age);
        userService.addUser(user);
    }

    @PutMapping(value = "/updateUser/{id}")
    public void updateUser(@PathVariable("id") Integer id,
                           @RequestParam("username") String username,
                           @RequestParam("password") String password,
                           @RequestParam("age") Integer age){
        User user = new User();
        user.setId(id);
        user.setUserName(username);
        user.setPassword(password);
        user.setAge(age);
        userService.updateUser(user);
    }

    @DeleteMapping("/deleteUser/{id}")
    public void deleteUser(@PathVariable("id") Integer id){
        userService.deleteUser(id);
    }
}

8、application.yml

spring:
  datasource:
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3308/user_test?useUnicode=true&useSSL=false&characterEncoding=UTF-8

server:
  port: 9090

mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.bysoft.springmybatismanual.entity

三、总结

注意事项：
1、启动类的包扫描一定要扫描上 实体类所在的包
2、mybatis要配置映射文件的位置 mapper-locations