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。
依赖
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.4.1</version>
</dependency>
service
//----接口---
public interface AccountService extends IService<Account> {
}
//----实现类----
@Service
public class AccountServiceImpl extends ServiceImpl<AccountMapper, Account> implements AccountService {
}
mapper继承BaseMapper(dao)
@Mapper
public interface AccountMapper extends BaseMapper<Account> {
}
分页拦截器
/**分页拦截器**/
@Configuration
public class MybatisConfig {
@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor() {
MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor());
return mybatisPlusInterceptor;
}
}
1.mybatis-plus自动生成id:@TableId()
2.mybatis-plus自动填充策略:@TableField()
@Data
public class User {
//@TableId(type = IdType.ID_WORKER) //mp自带策略,生成19位值,数字类型使用这种策略,比如long
//@TableId(type = IdType.ID_WORKER_STR) //mp自带策略,生成19位值,字符串类型使用这种策略
private Long id;
private String name;
private Integer age;
private String email;
@TableField(fill = FieldFill.INSERT)
private Date createTime;
@TableField(fill = FieldFill.INSERT_UPDATE)
private Date updateTime;
@Version
@TableField(fill = FieldFill.INSERT)
private Integer version;
@TableLogic
private Integer deleted;
}
自动填充需要实现MetaObjectHandler接口
@Component
public class MyMetaObjectHandler implements MetaObjectHandler {
//使用mp实现添加操作,这个方法执行
@Override
public void insertFill(MetaObject metaObject) {
this.setFieldValByName("createTime",new Date(),metaObject);
this.setFieldValByName("updateTime",new Date(),metaObject);
this.setFieldValByName("version",1,metaObject);
}
//使用mp实现修改操作,这个方法执行
@Override
public void updateFill(MetaObject metaObject) {
this.setFieldValByName("updateTime",new Date(),metaObject);
}
}