Springboot integrates mybatis

1. Introduce mybatis related jar packages

    pom.xml

<!-- 集成mybatis-->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.2</version>
</dependency>
<!-- 引入mysql连接jar包-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

2. Create related packages

The structure is as follows:

Fourth, improve the relevant code

   mapper file: UserDao.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">
<mapper namespace="com.example.springboot.dao.UserDao">
    <resultMap id="userResultMap" type="User">
        <result property="id" column="id"/>
        <result property="username"column="username"/>
        <result property

="password" column="password"/>
    </resultMap>
    <sql id="userColumns">
id  ,
         
         username  ,
         password  
   </sql>
    <select id="get" parameterType="long" resultMap="userResultMap">
select
        <include refid="userColumns"/>
from user
                
        where id = #{id}
    </select>
    <select id="find" parameterType="java.util.Map" resultMap="userResultMap">
select
        <include refid="userColumns"/>
from user
        <where>
            <if test="id != null">
id = #{id}
            </if>
            <if test="username != null">
username = #{username}
            </if>
            <if test="password != null">
password = #{password}
            </if>

                                                                        </where>
    </select>
    <select id="page" parameterType="java.util.Map" resultMap="userResultMap">
select
        <include refid="userColumns"/>
from user
        <where>
            <if test="id != null">
id = #{id}
            </if>
            <if test="username != null">
username = #{username}
            </if>
            <if test="password != null">
password = #{password}
            
                                                                </if>
        </where>
        LIMIT #{_start},#{_pageSize}
    </select>
    <select id="total" parameterType="java.util.Map" resultType="int">
select
        count(1)
        
        from user
        <where>
            <if test="id != null">
                id = #{id}
            </if>
            <if test="username != null">
                username = #{username}
            </if>
            <if test="password != null">
                password = #{password}
            </if>
        </where>
    </select>
    <insert id="save" parameterType="User">  
insert into user(
        
        #{id},
        #{username},
        #{password}
        )  
    </insert>
    <update id="update" parameterType="User">
update user
        <set>
            <if test="username != null">
username = #{username}
            </if>
            <if test="password != null">
password = #{password}
            </if>
        </set>
where id = #{id}
    </update>
    <delete id="delete" parameterType="long">
delete from user where
                                                
      
      id=#{id}
   </delete>

</mapper>  

    dao 文件： UserDao.java

package com.example.springboot.dao;


import com.example.springboot.entity.User;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;
import java.util.Map;

@Mapper
public interface UserDao {
   
   User get(Long id);

   List<User> find(Map map);

   int total(Map map);

   boolean save(User user);

   boolean update(User user);

   int delete(Long id);
}

entity文件：User.java

package com.example.springboot.entity;

public class User {

    private Long id;
    private String username;
    private String password;

    public Long getId(){
      return id;
    }
    public void setId(Long id){
      this.id = id;
    }
    public String getUsername(){
      return username;
    }
    public void setUsername(String username){
      this.username = username;
    }
    public String getPassword(){
      return password;
    }
    public void setPassword(String password){
      this.password = password;
    }
}

service接口：IUserService.java

package com.example.springboot.service;

import com.example.springboot.entity.User;

import java.util.List;
import java.util.Map;

public interface IUserService {
   
   User get(Long id);

   List<User> find(Map map);

   boolean save(User user);

   boolean update(User user);

   int delete(Long id);
}

service实现类：UserService.java

package com.example.springboot.service.impl;

import com.example.springboot.dao.UserDao;
import com.example.springboot.entity.User;
import com.example.springboot.service.IUserService;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.util.List;
import java.util.Map;

@Service
public class UserService implements IUserService {

    @Resource
    private UserDao userDao;

    @Override
    public User get(Long id) {
        return userDao.get(id);
    }

    @SuppressWarnings("rawtypes")
    @Override
    public List<User> find(Map map) {

        return userDao.find(map);
    }

    @Override
    public boolean save(User user) {
        return userDao.save(user);
    }

    @Transactional
    @Override
    public boolean update(User user) {
        return userDao.update(user);
    }

    @Override
    public int delete(Long id) {
        return userDao.delete(id);
    }
}

controller类：UserController.java

package com.example.springboot.controller;

import com.example.springboot.entity.User;
import com.example.springboot.service.IUserService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/user")
@Validated
public class UserController {

    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    @Autowired
    private IUserService userService;

    @GetMapping("/get")
    public User getUser(Long id) {
        return userService.get(id);
    }
}

配置文件：application.yaml

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/demo?useSSL=false&useUnicode=true&characterEncoding=utf-8
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver
mybatis:
  mapperLocations: classpath:mapper/*.xml
  typeAliasesPackage: com.example.springboot.entity

启动项目

访问：http://localhost:8080/user/get?id=1