Spring Boot菜鸟示例——MyBatis-plus简单示例

创建数据库MP与表User并添加字段

// 创建数据库 略

// 创建表
CREATE TABLE Test.`User` (
	id INT auto_increment NOT NULL COMMENT '自增主键',
	name varchar(100) NULL COMMENT '姓名',
	password varchar(100) NULL COMMENT '密码',
	account varchar(100) NOT NULL,
	CONSTRAINT User_PK PRIMARY KEY (id),
	CONSTRAINT User_UN UNIQUE KEY (account)
)
ENGINE=InnoDB
DEFAULT CHARSET=utf8mb4
COLLATE=utf8mb4_0900_ai_ci;


// 添加数据条
--  Auto-generated SQL script #202207052210
INSERT INTO Test.`User` (name,password,account)
	VALUES ('hiyj1','123456','hiyj1acc');
INSERT INTO Test.`User` (name,password,account)
	VALUES ('hiyj2','654321','hiyj2acc');

项目结构

额外的依赖

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.8</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.1.0</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
            <scope>compile</scope>
        </dependency>

重命名application.properties配置文件为application.yml格式，更好用，并添加mysql配置信息

server:
  port: 8888
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.NonRegisteringDriver
    type: com.alibaba.druid.pool.DruidDataSource

    # 主要
    url: jdbc:mysql://127.0.0.1/Test
    # 主要
    username: root
    # 主要
    password: root

    # 下边的一些其他参数，照抄就行
    filters: stat
    initialSize: 2
    maxActive: 300
    maxWait: 60000
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: false
    maxPoolPreparedStatementPerConnectionSize: 200

编写User类，用来对应数据库的表信息

import lombok.Data;

import java.io.Serializable;

// 自动添加get\set\toString方法
@Data
// 实现序列化，方便直接将对象转成字符串发出去
public class User implements Serializable {
    private int id;
    private String account;
    private String name;
    private String password;
}

编写Mybatis-plus的UserMapper接口，用来查询数据库的

// Mybatis-plus包，需要添加依赖
import cn.hiyj.mp.mpex.object.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

import java.util.List;

// @Mapper声明这个接口是一个Mapper，会自动交给Spring Boot框架管理这个接口
@Mapper
public interface UserMapper {
    // 获取所有User，自动将一行一行的数据生成User对象并返回List<User>
    @Select("select * from user")
    List<User> getUsers();

    // 根据user的account查找User，@Param("user")，表示传入的参数命名为user在sql中使用
    // #{user.account}，获取@Param("user")传来的user对象的account属性
    @Select("select * from user where account = #{user.account}")
    User findUser(@Param("user") User user);
}

编写Controller层UserController代码

package cn.hiyj.mp.mpex.controller;

import cn.hiyj.mp.mpex.mapper.UserMapper;
import cn.hiyj.mp.mpex.object.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping(value = "user")
public class UserController {
    private UserMapper userMapper;

    // @Autowired可以直接加到变量头上，但是会有黄线
    // @Autowired可以从Spring Boot框架管理的Bean中直接获取，不用自己初始化
    // Spring Boot框架管理的Bean，可以通过添加注解来添加，例如@Mapper、@RestController等这类的都会由
    // Spring Boot框架管理这些Bean，不过一般的类有其他的注解，@Mapper、@RestController这几个是有专用功能的
    @Autowired
    public void setUserMapper(UserMapper userMapper) {
        this.userMapper = userMapper;
    }

    // 获取对象列表，会自动转为json格式字符串
    @GetMapping(value = "getUsers")
    public List<User> getUsers() {
        return userMapper.getUsers();
    }

    @PostMapping(value = "login")
    public String login(@RequestBody User user) {
        //直接通过Mapper接口查询
        User search = userMapper.findUser(user);
        if (search == null) {
            return "用户不存在";
        } else if (search.getPassword().equals(user.getPassword())) {
            return "登录成功";
        } else {
            return "密码错误";
        }
    }
}

运行测试

账户1：hiyj1acc 密码：123456
账户12：hiyj2acc 密码：654321

curl http://localhost:8888/user/getUsers

curl -X POST -H "Content-Type: application/json" -d"{\"account\":\"hiyj1acc\",\"password\": \"123456\"}" http://localhost:8888/user/login

curl -X POST -H "Content-Type: application/json" -d"{\"account\":\"hiyj1acc\",\"password\": \"654321\"}" http://localhost:8888/user/login

curl -X POST -H "Content-Type: application/json" -d"{\"account\":\"hiyj2acc\",\"password\": \"654321\"}" http://localhost:8888/user/login