Master MyBatis-Plus in Spring Boot: From Setup to Advanced Features

Quick Start

Prepare a Spring Boot, Maven, JDK 1.8, and MySQL environment; optionally use Nacos as a service registry.

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>

Configuration

Configure the main class with @MapperScan and @EnableDiscoveryClient.

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

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

Define datasource properties for master and slave (utf8mb4 charset is recommended).

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

Adjust HikariCP settings for connection pool stability.

spring:
  datasource:
    dynamic:
      hikari:
        max-lifetime: 1800000
        connection-timeout: 5000
        idle-timeout: 3600000
        max-pool-size: 12
        min-idle: 4
        connection-test-query: /**ping*/

Usage

Entity Annotations

Use @TableName, @TableId, and @TableField to map Java classes to database tables.

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

@TableName specifies the table name.

@TableId defines the primary key and its generation strategy.

@TableField customizes column name and query condition.

CRUD Operations

Service layer extends IService; implementation extends ServiceImpl.

public interface IUserService extends IService<UserDO> {}

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

Mapper extends BaseMapper.

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

Pagination

Configure MybatisPlusInterceptor with PaginationInnerInterceptor.

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

Logical Delete

Set global logical‑delete configuration or annotate a field with @TableLogic.

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

@TableLogic
private Integer isDelete;

Enum Mapping

Implement IEnum and use @JsonFormat to serialize enum values.

@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; }
}

Configure the package for enum scanning and set the default enum type handler.

mybatis-plus:
  typeEnumsPackage: com.wjbgn.*.enums

@Bean
public MybatisPlusPropertiesCustomizer mybatisPlusPropertiesCustomizer() {
    return properties -> {
        GlobalConfig globalConfig = properties.getGlobalConfig();
        globalConfig.setBanner(false);
        MybatisConfiguration configuration = new MybatisConfiguration();
        configuration.setDefaultEnumTypeHandler(MybatisEnumTypeHandler.class);
        properties.setConfiguration(configuration);
    };
}

Auto Fill

Use FieldFill in @TableField and implement MetaObjectHandler to populate timestamps.

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

@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());
    }
}

Multi‑Datasource

Define multiple master/slave or different database types in the dynamic datasource configuration.

spring:
  datasource:
    dynamic:
      primary: master
      datasource:
        master_1: ...
        slave_1: ...
        # additional datasources

Testing

Create the user table, implement a REST controller for CRUD and pagination, and verify the endpoints.

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

    @PostMapping("/save")
    public boolean save() {
        UserDO user = new UserDO();
        user.setNickname("大漂亮");
        user.setSex(SexEnum.MAN);
        return userService.save(user);
    }
    // other endpoints for update, delete, list, page ...
}