整合篇：零基础学习与使用MyBatis-Plus

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注意：学习MyBatis-Plus请参考我的另外一篇文章：https://caochenlei.blog.csdn.net/article/details/108809902

1、创建工程

2、导入依赖

导入数据库连接池场景启动器：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.2.4</version>
</dependency>

导入mybatis-plus场景启动器：

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.4.1</version>
</dependency>

修改默认数据库连接驱动为5.x：

<properties>
    <java.version>1.8</java.version>
    <mysql.version>5.1.49</mysql.version>
</properties>

3、修改配置

创建包结构：

• com.caochenlei.integrationmybatis.entity
• com.caochenlei.integrationmybatis.vo
• com.caochenlei.integrationmybatis.mapper
• com.caochenlei.integrationmybatis.service
• com.caochenlei.integrationmybatis.controller

创建数据库：

DROP DATABASE IF EXISTS `test`;

CREATE DATABASE `test`;

USE `test`;

DROP TABLE IF EXISTS `t_user`;

CREATE TABLE `t_user` (
  `uid` INT(11) NOT NULL AUTO_INCREMENT,
  `uname` VARCHAR(20) NOT NULL,
  `ugender` VARCHAR(20) NOT NULL,
  `uage` INT(11) NOT NULL,
  PRIMARY KEY (`uid`)
) ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO `test`.`t_user` (`uname`, `ugender`, `uage`) VALUES ('张三', '男', '18'); 
INSERT INTO `test`.`t_user` (`uname`, `uage`) VALUES ('李四', '女', '19'); 
INSERT INTO `test`.`t_user` (`uname`, `uage`) VALUES ('王五', '20'); 

配置数据源：

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: 123456
    #druid控制台访问地址：http://localhost:8080/druid
    druid:
      filters: stat,wall
      stat-view-servlet:
        enabled: true
        login-username: admin
        login-password: admin
      web-stat-filter:
        enabled: true
        urlPattern: /*
        exclusions: '*.css,*.js,*.gif,*.jpg,*.png,*.ico,/druid/*'

mybatis-plus:
  #配置 mybatis 配置文件位置
  config-location: classpath:mybatis/mybatis-config.xml
  #配置 mybatis 映射文件位置
  mapper-locations: classpath:mybatis/mapper/*.xml

4、增删改查

com.caochenlei.integrationmybatis.vo.Result

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Result {
    private Boolean success;
    private Object data;
    private String message;
}

com.caochenlei.integrationmybatis.entity.User

@Data
@TableName("t_user")
public class User{
    @TableId(type = IdType.AUTO)
    private Integer uid;
    @TableField("uname")
    private String uname;
    @TableField("ugender")
    private String ugender;
    @TableField("uage")
    private Integer uage;
}

com.caochenlei.integrationmybatis.mapper.UserMapper

@Mapper
public interface UserMapper extends BaseMapper<User> {

}

src\main\resources\mybatis\mapper\UserMapper.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.caochenlei.integrationmybatis.mapper.UserMapper">

</mapper>

src\main\resources\mybatis\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>

</configuration>

com.caochenlei.integrationmybatis.service.UserService

public interface UserService extends IService<User> {

}

com.caochenlei.integrationmybatis.service.impl.UserServiceImpl

@Service
@Transactional
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {
    
}

com.caochenlei.integrationmybatis.controller.UserController

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

    //查找一个用户
    @GetMapping("/users/{id}")
    public Result findOne(@PathVariable Integer id) {
        User user = userService.getById(id);
        return new Result(true, user, "操作成功");
    }

    //查找所有用户
    @GetMapping("/users")
    public Result findAll() {
        List<User> users = userService.list();
        return new Result(true, users, "操作成功");
    }

    //添加一个用户
    @PostMapping("/users")
    public Result save(@RequestBody User user) {
        boolean flag = userService.save(user);
        if (flag) {
            return new Result(true, 1, "操作成功");
        } else {
            return new Result(false, 0, "操作失败");
        }
    }

    //删除一个用户
    @DeleteMapping("/users/{id}")
    public Result delete(@PathVariable Integer id) {
        boolean flag = userService.removeById(id);
        if (flag) {
            return new Result(true, "操作失败");
        }
    }

    //修改一个用户
    @PutMapping("/users")
    public Result update(@RequestBody User user) {
        boolean flag = userService.updateById(user);
        if (flag) {
            return new Result(true, "操作失败");
        }
    }
}

5、测试接口

• 查找一个用户

• 查找所有用户

• 添加一个用户

• 删除一个用户

• 修改一个用户