Spring Boot+MyBatis+Mysql

添加依赖

引入 lombok、mysql-connector-java 、mybatis-plus-boot-starter 依赖：

org.projectlombok

lombok

true

mysql

mysql-connector-java

5.1.44

com.baomidou

mybatis-plus-boot-starter

3.3.2

配置

在 application.properties 配置文件中添加 mysql数据库的相关配置

#数据库配置

spring.datasource.url=jdbc:mysql://localhost:3306/test?serverTimezone=UTC

spring.datasource.username=root

spring.datasource.password=root

spring.datasource.driver-class-name=com.mysql.jdbc.Driver

在 Spring Boot 启动类中添加 @MapperScan 注解，扫描 Mapper 目录：

@SpringBootApplication

@MapperScan("com.baomidou.mybatisplus.samples.quickstart.mapper")

public class Application {

public static void main(String[] args) {

SpringApplication.run(QuickStartApplication.class, args);

}

}

注：MapperScan后面的路径必须是自己mapper文件的目录

编码

1、编写实体类 User.java

package com.example.demo.entity;

import com.baomidou.mybatisplus.annotation.TableName;

import lombok.Data;

@Data

@TableName(value = "user")

public class User {

private Long id;

private String name;

private Integer age;

private String email;

}

2、编写Mapper类 UserMapper.java

package com.example.demo.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;

import com.example.demo.entity.User;

public interface UserMapper extends BaseMapper {

}

3、编写Controller类 UserController.java

package com.example.demo;

import com.example.demo.entity.User;

import com.example.demo.mapper.UserMapper;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.ResponseBody;

import org.springframework.web.bind.annotation.RestController;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

@Controller

public class UserController {

@Autowired

private UserMapper userMapper;

@ResponseBody

@RequestMapping("/")

public Map index(){

Map result = new HashMap<>(16);

List data = new ArrayList<>();

result.put("errCode",0);

result.put("errMsg","获取成功");

List list=userMapper.selectList(null);

if(list!=null&&list.size()>0){

for(User g:list){

data.add(g.toString());

}

}else{

result.put("errMsg","获取失败");

}

result.put("data",data);

return result;

}

}

调试

1、测试

@RunWith(SpringRunner.class)

@SpringBootTest

public class SampleTest {

@Autowired

private UserMapper userMapper;

@Test

public void testSelect() {

System.out.println(("----- selectAll method test ------"));

List userList = userMapper.selectList(null);

Assert.assertEquals(5, userList.size());

userList.forEach(System.out::println);

}

}

注：UserMapper 中的 selectList() 方法的参数为 MP 内置的条件封装器 Wrapper，所以不填写就是无任何条件

控制台输出：

User(id=1, name=Jone, age=18, email=test1@baomidou.com)

User(id=2, name=Jack, age=20, email=test2@baomidou.com)

User(id=3, name=Tom, age=28, email=test3@baomidou.com)

User(id=4, name=Sandy, age=21, email=test4@baomidou.com)

User(id=5, name=Billie, age=24, email=test5@baomidou.com)

2、浏览器访问

输出结果

{

"data": [

"User{id=1, name='Jone', age=18, email='test1@baomidou.com'}",

"User{id=2, name='Jack', age=20, email='test2@baomidou.com'}",

"User{id=3, name='Tom', age=28, email='test3@baomidou.com'}",

"User{id=4, name='Sandy', age=21, email='test4@baomidou.com'}",

"User{id=5, name='Billie', age=24, email='test5@baomidou.com'}"

],

"errCode": 0,

"errMsg": "获取成功"

}

数据库

1、User 表，其结构如下：

DROP TABLE IF EXISTS user;

CREATE TABLE user

(

id BIGINT(20) NOT NULL COMMENT '主键ID',

name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',

age INT(11) NULL DEFAULT NULL COMMENT '年龄',

email VARCHAR(50) NULL DEFAULT NULL COMMENT '邮箱',

PRIMARY KEY (id)

);

3、其对应的数据库 Data 脚本如下：

DELETE FROM user;

INSERT INTO user (id, name, age, email) VALUES

(1, 'Jone', 18, 'test1@baomidou.com'),

(2, 'Jack', 20, 'test2@baomidou.com'),

(3, 'Tom', 28, 'test3@baomidou.com'),

(4, 'Sandy', 21, 'test4@baomidou.com'),

(5, 'Billie', 24, 'test5@baomidou.com');

小结

通过以上几个简单的步骤，我们就实现了 User 表的 CRUD 功能，甚至连 XML 文件都不用编写！

从以上步骤中，我们可以看到集成 MyBatis-Plus 非常的简单，只需要引入 starter 工程，并配置 mapper 扫描路径即可。