SpringBoot整合Mybatis-Plus

持久层

SpringBoot整合Mybatis-Plus-LMLPHP

Mybatis-Plus 介绍

MyBatis-Plus（简称 MP）是一个 MyBatis的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。
Mybatis-Plus官网

整合步骤

1、创建数据库springboot；创建一张user表，表结构为

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  `age` int(11) DEFAULT NULL,
  `email` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES ('1', 'Jone', '18', 'test1@baomidou.com');
INSERT INTO `user` VALUES ('2', 'Jack', '20', 'test2@baomidou.com');
INSERT INTO `user` VALUES ('3', 'Tom', '28', 'test3@baomidou.com');
INSERT INTO `user` VALUES ('4', 'Sandy', '21', 'test4@baomidou.com');
INSERT INTO `user` VALUES ('5', 'Billie', '24', 'test5@baomidou.com');

2、添加Mybatis-plus依赖和mysql依赖

        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.2</version>
        </dependency>

        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>

3、配置数据源

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/springboot
spring.datasource.username=root
spring.datasource.password=root

4、在 Spring Boot 启动类中添加 @MapperScan 注解，扫描 Mapper 文件夹

@SpringBootApplication
@MapperScan("cn.qvtu.web.mapper")
public class QvtuWeb04Application {

    public static void main(String[] args) {
        SpringApplication.run(QvtuWeb04Application.class, args);
    }

}

5、编写实体类 User.java

@TableName("user")
public class User {

    @TableId(type = IdType.AUTO)
    private Long id;
    private String name;
    private Integer age;
    private String email;
    
	//getter setter省略...
}

6、编写 Mapper 包下的 UserMapper接口

@Mapper
public interface UserMapper extends BaseMapper<User> {

}

7、通用 Service CRUD 封装IService接口

进一步封装 CRUD 采用 get 查询单行 remove 删除 list 查询集合 page 分页前缀命名方式区分 Mapper 层避免混淆，

public interface IUserService extends IService<User> {

}

@Service
public class UserServiceImpl extends ServiceImpl<UserMapper,User> implements IUserService {

}

8、实现CRUD

新增UserController实现UserCRUD
API：具体API查看

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

    @Autowired
    private IUserService userService;

    /**
     * 添加用户
     */
    @GetMapping("/add")
    public String add(String name){
        User user = new User();
        user.setName(name);
        boolean b = userService.save(user);
        return b ? "success":"failure";
    }

    /**
     * 删除用户
     */
    @GetMapping("/delete")
    public String delete(Integer id){
        boolean b = userService.removeById(id);
        return b ? "success":"failure";
    }

    /**
     * 更新用户
     */
    @GetMapping("/update")
    public String update(Integer id ,String name){
        User user = userService.getById(id);
        user.setName(name);
        boolean b = userService.saveOrUpdate(user);
        return b ? "success":"failure";
    }

    /**
     * 查询所有用户
     */
    @GetMapping("/find")
    public List<User> find(){
        return userService.list();
    }

}