Master MyBatis-Plus with Spring Boot: Complete Guide to CRUD, Pagination, and Multi‑DataSource

Quick Start

This article introduces MyBatis-Plus for Spring Boot, covering dependency setup, configuration, and common usage.

1. Dependency Setup

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.5.0</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.27</version>
</dependency>
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
    <version>3.5.0</version>
</dependency>

2. Configuration

Configure the Spring Boot main class, data source properties, and MyBatis‑Plus interceptor for pagination.

@SpringBootApplication
@EnableDiscoveryClient
@MapperScan("com.wjbgn.user.mapper")
public class RobNecessitiesUserApplication {
    public static void main(String[] args) {
        SpringApplication.run(RobNecessitiesUserApplication.class, args);
    }
}

spring:
  datasource:
    dynamic:
      primary: master
      strict: false
      datasource:
        master:
          url: jdbc:mysql://127.0.0.1:3306/rob_necessities?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=Asia/Shanghai
          username: root
          password: 123456
        slave_1:
          url: jdbc:mysql://127.0.0.1:3306/rob_necessities?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=Asia/Shanghai
          username: root
          password: 123456

@Configuration
@MapperScan("com.wjbgn.*.mapper")
public class MybatisPlusConfig {
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }
}

3. Entity Annotations

@TableName("user")
public class UserDO {
    @TableId(value = "id", type = IdType.AUTO)
    private Long id;

    @TableField("nickname")
    private String nickname;

    @TableField("sex")
    private SexEnum sex;

    @TableField(value = "create_time", fill = FieldFill.INSERT)
    private LocalDateTime createTime;
}

4. CRUD Service and Mapper

public interface IUserService extends IService<UserDO> {}

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

@Mapper
public interface UserMapper extends BaseMapper<UserDO> {}

5. Pagination

Page<UserDO> page = userService.page(new Page<>(current, size), new QueryWrapper<>(new UserDO()));

6. Logical Delete

@TableLogic
private Integer isDelete;

mybatis-plus:
  global-config:
    db-config:
      logic-delete-field: isDelete
      logic-delete-value: 1
      logic-not-delete-value: 0

7. Enum Mapping

@JsonFormat(shape = JsonFormat.Shape.OBJECT)
public enum SexEnum implements IEnum<Integer> {
    MAN(1, "男"),
    WOMAN(2, "女");
    private Integer code;
    private String name;
    @Override
    public Integer getValue() { return code; }
    public String getName() { return name; }
}

mybatis-plus:
  type-enums-package: com.wjbgn.*.enums

8. Automatic Field Fill

@Component
public class MyMetaObjectHandler implements MetaObjectHandler {
    @Override
    public void insertFill(MetaObject metaObject) {
        this.strictInsertFill(metaObject, "createTime", LocalDateTime.class, LocalDateTime.now());
    }
    @Override
    public void updateFill(MetaObject metaObject) {
        this.strictUpdateFill(metaObject, "updateTime", LocalDateTime.class, LocalDateTime.now());
    }
}

9. Multi‑DataSource

Define multiple master/slave data sources in application.yml and use @DS("slave_1") on service methods to switch.

10. Testing Controller

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

    @RequestMapping("/save")
    public boolean save() {
        UserDO user = new UserDO();
        user.setNickname("大漂亮");
        user.setSex(SexEnum.MAN);
        return userService.save(user);
    }
    // other CRUD endpoints omitted for brevity
}

After following the steps, the application runs successfully and demonstrates the main features of MyBatis‑Plus.