Springboot+MybatisPlus入门案例（postman测试）

 一、项目框架

pom.xml依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.yh</groupId>
    <artifactId>yh-mp-springboot</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.10.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--简化代码的工具包，针对实体类-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--mybatis‐plus的springboot支持-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.1.0</version>
        </dependency>
        <!--mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.30</version>
        </dependency>

    </dependencies>

</project>

config包-分页插件配置文件

MybatisPlusConfig

import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MybatisPlusConfig {
    /**
     * 分页插件
     */
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        return new PaginationInterceptor();
    }
}

controller层

package org.example.controller;

import org.example.pojo.User;
import org.example.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

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

    @Autowired
    private UserService userService;

    @PostMapping("/addUser")
    public void addUser(@RequestBody User user) {
        userService.addUser(user);
    }

    @DeleteMapping("/deleteUserById/{id}")
    public void deleteUserById(@PathVariable Long id) {
        userService.deleteUserById(id);
    }

    @PutMapping("/updateUser")
    public void updateUser(@RequestBody User user) {
        userService.updateUser(user);
    }


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

    @GetMapping("/getAllUser")
    public List<User> getAllUser() {
        return userService.getAllUser();
    }

    @PostMapping("/addUserList")
    public void addUserList(@RequestBody List<User> users) {
        userService.addUserList(users);
    }
}

Mapper层

UserMapper

public interface UserMapper extends BaseMapper<User> {
    User myFindUserById(Integer id); //自定义的查询方法，目的是练习传统Mybatis的使用
}

Pojo实体类

User

package org.example.pojo;

import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.time.LocalDateTime;

@Data
@AllArgsConstructor
@NoArgsConstructor
@TableName("tb_user")   //指定数据库表
public class User {


    /**
     * 指定主键
     * <p>
     * 使用该主键生成策略：@TableId(value = "id",type = IdType.ID_WORKER) 要注意下面内容
     * 如果数据库id字段是bigint类型，那么java实体类中属性类型为java.long.Long,Integer位数远远不够了
     */
    @TableId(value = "id")
    private Long id;

    //    @TableField("user_name")   //mybatis-plus默认开启驼峰匹配，可不写@TableField("user_name")
    private String userName;

    //    @TableField("password")
    private String password;

    //    @TableField("age")
    private Integer age;

    //    @TableField("birthday")
    private LocalDateTime birthday; //数据库中日期类型为datetime没有时分秒

}

service层

UserService

package org.example.service;

import org.example.pojo.User;

import java.util.List;

public interface UserService {
    void addUser(User user);

    void deleteUserById(Long id);

    void updateUser(User user);

    User getUserById(Long id);


    List<User> getAllUser();

    void addUserList(List<User> users);

}

UserService实现类UserServiceImp

package org.example.service;

import org.example.mapper.UserMapper;
import org.example.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImp implements UserService {

    @Autowired
    private UserMapper userMapper;

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

    @Override
    public void deleteUserById(Long id) {
        userMapper.deleteById(id);
    }

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

    @Override
    public User getUserById(Long id) {
        return userMapper.selectById(id);
    }

    @Override
    public List<User> getAllUser() {
        return userMapper.selectList(null);
    }

    @Override
    public void addUserList(List<User> users) {
        for (User user : users) {
            userMapper.insert(user);
        }
    }
}

引导类/启动类

Application 

@MapperScan("org.example.mapper") 扫描对应包下的接口并加到Spring的Ioc容器中。

package org.example;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan("org.example.mapper")
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

resources配置

UserMapper

<?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">

<!--namespace是mapper层对应的接口名-->
<mapper namespace="org.example.mapper.UserMapper">

    <!--id是mapper层对应的接口名中对应的方法名-->
    <select id="myFindUserById" resultType="User">
        select *
        from tb_user
        where id = #{id}
    </select>


</mapper>

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--设置驼峰匹配，MybatisPlus默认开启驼峰匹配-->
<!--    <settings>-->
<!--        <setting name="mapUnderscoreToCamelCase" value="true"/>-->
<!--    </settings>-->

</configuration>

application.yml

server:
  port: 8082 #指定端口号
spring:
  application: #服务名
    name: local-mp
  #数据源，连接自己电脑上的数据库
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver   #MySQL8版本及以上要加cj,此工程用的是MySQL8
    username: root
    password: "123456"       #注意url有问题时可以尝试加时区，url中的test为数据库名
    url: jdbc:mysql://localhost:3306/test?characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai&rewriteBatchedStatements=true



#日志
logging:
  level:
    root: debug


#设置mybatis-plus
mybatis-plus:
  config-location: classpath:mybatis/mybatis-config.xml  #配置文件
  mapper-locations: classpath:mybatis/mapper/*.xml  #设置mapper层对应的接口对应的mapper.xml的路径
  type-aliases-package: org.example.pojo  #设置别名，mapper.xml中resultType="cn.yh.mp.pojo.User"可省去包，即resultType="User"
  #开启自动驼峰映射，注意：配置configuration.map-underscore-to-camel-case则不能配置config-location，可写到mybatis-config.xml中
#  configuration:
#    map-underscore-to-camel-case: true

二、Sql

/*
 Navicat Premium Data Transfer

 Source Server         : localhost
 Source Server Type    : MySQL
 Source Server Version : 80033 (8.0.33)
 Source Host           : localhost:3306
 Source Schema         : test

 Target Server Type    : MySQL
 Target Server Version : 80033 (8.0.33)
 File Encoding         : 65001

 Date: 30/04/2024 00:23:33
*/

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for tb_user
-- ----------------------------
DROP TABLE IF EXISTS `tb_user`;
CREATE TABLE `tb_user`  (
  `id` bigint NOT NULL AUTO_INCREMENT,
  `user_name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  `password` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,
  `age` int NULL DEFAULT NULL,
  `birthday` datetime NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 1784973424016379907 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of tb_user
-- ----------------------------
INSERT INTO `tb_user` VALUES (1784972199497822210, 'jack', '123', 25, '2024-04-29 00:00:00');
INSERT INTO `tb_user` VALUES (1784972897228660738, 'tom', '123', 24, '2024-04-29 00:00:00');
INSERT INTO `tb_user` VALUES (1784973068603641857, '优雅修改', 'password2', 30, '2024-04-29 00:00:00');

SET FOREIGN_KEY_CHECKS = 1;

三、Postman准备

postman准备

以person举例，在本项目中为user，步骤都一样，名字不同而已。

创建-Collections

创建请求-Request

请求介绍

1 新增：

请求方式：Post 请求路径：http://localhost:8082/user/addUser

传递数据：

  {
    "userName": "tom2",
    "password": "123",
    "age": 24,
    "birthday": "2024-04-29T15:59:26.302"
  }

2 删除：

请求方式：DELETE 请求路径：http://localhost:8082/user/deleteUserById/1784972199497822210

3 修改：

请求方式：Put 请求路径：http://localhost:8082/user/updateUser

  {
    "id": 1784973068603641857,
    "userName": "优雅修改",
    "password": "password2",
    "age": 30,
    "birthday": "2024-04-29T15:59:26.302"
  }

4 查询：

请求方式：Get 请求路径：http://localhost:8082/user/getUserById?id=1784972897228660738

四、测试类

不想通过postman测试的，也可以在Test包中创建测试类自测（单元测试），测试类自测不通过controller及service。

MapperPlusTest

import cn.yh.mp.mapper.UserMapper;
import cn.yh.mp.pojo.User;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.Arrays;
import java.util.List;

@SpringBootTest
@RunWith(SpringRunner.class)
public class MapperPlusTest {

    @Autowired
    private UserMapper userMapper;

    @Test
    public void selectAll() {
        List<User> users = userMapper.selectList(null);
        for (User user : users) {
            System.out.println(user);
        }
    }

    @Test
    public void findUserById() {
        User user = userMapper.myFindUserById(2);
        System.out.println(user);
    }

    /**
     * 插入数据
     */
    @Test
    public void testInsert() {
        User user = new User();
        user.setAge(20);
        user.setEmail("test@yh.cn");
        user.setName("曹操");
        user.setUserName("caocao");
        user.setPassword("123456");
        userMapper.insert(user);

    }


    /**
     * 根据id 批量删除
     */
    @Test
    public void testDeleteByIds() {
//根据id集合批量删除   DELETE FROM tb_user WHERE ID IN ( ? , ? , ? )
        int result = this.userMapper.deleteBatchIds(Arrays.asList(1, 2, 4));
        System.out.println("result   = " + result);
    }


    /**
     * 分页
     */
    @Test
    public void testPage() {
        QueryWrapper<User> wrapper = new QueryWrapper<User>();
        wrapper.eq("age", 20); //查询条件，age=20

        IPage<User> page = new Page<>(1, 2);


        IPage<User> userIPage = userMapper.selectPage(page, wrapper);
        System.out.println("数据总条数：" + userIPage.getTotal());
        System.out.println("总页数:" + userIPage.getPages());
    }


    /**
     * 修改
     */
    @Test
    public void testUpdate() {
        User user = new User();
        user.setId(5L);
        user.setAge(20);
        user.setEmail("test@yh.cn");
        user.setName("曹操");
        user.setUserName("caocao");
        user.setPassword("123");

        userMapper.updateById(user);

//        userMapper.update()
    }


    /**
     * 模糊查询
     */
    @Test
    public void testLike() {
        LambdaQueryWrapper<User> wrapper = new LambdaQueryWrapper<>();
//        wrapper.like(User::getName, "曹");   //%曹%
        wrapper.likeRight(User::getName, "曹");  //曹%
        List<User> userList = userMapper.selectList(wrapper);
        userList.forEach(System.out::println);


        userMapper.selectList(wrapper);
    }

    /**
     * 测试or,默认and拼接条件
     */
    @Test
    public void testOr() {
        LambdaQueryWrapper<User> lambdaQueryWrapper = new LambdaQueryWrapper<>();
        lambdaQueryWrapper.eq(User::getName, "曹丕");
        lambdaQueryWrapper.or();   //添加or条件
        lambdaQueryWrapper.eq(User::getAge, 22);

        /**
         * SELECT id,user_name,password,name,age,email,birthday FROM tb_user
         * WHERE name = ? OR age = ?
         */
        List<User> userList = userMapper.selectList(lambdaQueryWrapper);
        userList.forEach(System.out::println);

    }


    //代码功能：在name为"张三", "李四", "王五"中 筛选password=123 或者age>20的人。
    @Test
    public void testLogicSelect() {
        QueryWrapper<User> wrapper = new QueryWrapper<>();
        wrapper.and(wp -> wp
                        .eq("password", "123")
                        .or()
                        .ge("age", 20))
                .in("name", "张三", "李四", "王五");

        /**
         * SELECT id,user_name,password,name,age,email,birthday FROM tb_user
         * WHERE password = ? OR age >= ? AND name IN (?,?,?)
         * 在 MySQL 中，AND 的优先级高于 OR。这意味着当一个查询语句中同时包含 AND 和 OR 运算符                    时，AND 将首先执行，然后才是OR。
         */
        List<User> userList = userMapper.selectList(wrapper);
        userList.forEach(user -> System.out.println(user));
    }


}