Spring Boot整合MyBatis-Plus实现CRUD操作的示例代码

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.5.3.1</version>
</dependency>

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mp_demo?useSSL=false&serverTimezone=Asia/Shanghai
    username: root
    password: 123456

mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl # 开启SQL日志
  global-config:
    db-config:
      id-type: assign_id # 主键生成策略（使用雪花算法）

@Data
@TableName("t_user") // 指定表名
public class User {
    @TableId(type = IdType.ASSIGN_ID) // 雪花算法生成ID
    private Long id;
    private String username;
    private Integer age;
    private String email;
}

@Mapper
public interface UserMapper extends BaseMapper<User> {
    // 继承BaseMapper后已包含基础CRUD方法
}

@Service
public class UserService {
    @Autowired
    private UserMapper userMapper;

    // 插入
    public int addUser(User user) {
        return userMapper.insert(user);
    }

    // 查询全部
    public List<User> getAllUsers() {
        return userMapper.selectList(null);
    }

    // 条件查询
    public User getUserById(Long id) {
        return userMapper.selectById(id);
    }

    // 更新
    public int updateUser(User user) {
        return userMapper.updateById(user);
    }

    // 删除
    public int deleteUser(Long id) {
        return userMapper.deleteById(id);
    }
}

@Configuration
public class MybatisPlusConfig {
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }
}

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;

    @PostMapping
    public String add(@RequestBody User user) {
        userService.addUser(user);
        return "插入成功";
    }

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

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

    @PutMapping
    public String update(@RequestBody User user) {
        userService.updateUser(user);
        return "更新成功";
    }

    @DeleteMapping("/{id}")
    public String delete(@PathVariable Long id) {
        userService.deleteUser(id);
        return "删除成功";
    }
}

{
    "username": "张三",
    "age": 25,
    "email": "zhangsan@example.com"
}

// 在Mapper中添加：
@Select("SELECT * FROM t_user WHERE age > #{age}")
Page<User> selectPageByAge(Page<User> page, @Param("age") Integer age);

// Controller调用：
@GetMapping("/page")
public Page<User> page(@RequestParam(defaultValue = "1") Integer pageNum,
                      @RequestParam(defaultValue = "10") Integer pageSize) {
    Page<User> page = new Page<>(pageNum, pageSize);
    return userMapper.selectPage(page, null);
}

QueryWrapper<User> wrapper = new QueryWrapper<>();
wrapper.like("username", "张").lt("age", 30);
userMapper.selectList(wrapper);