一、注解
@TableName(value = "person")//指定表名 @TableId(value = "id",type = IdType.AUTO)//指定主键名及自增 @TableField(value = "name")//指定字段名 @TableField(exist = false)//表中不存在的字段
二、增
// modifyNum:返回数据库影响条数 Integer modifyNum = personMapper.insert(person); // person.getId()：插入完成后，获取插入的id System.out.println(person.getId());
三、删
Integer modifyNum = personMapper.deleteById(id); Integer modifyNum = personMapper.deleteBatchIds(idList); Integer modifyNum = personMapper.deleteByMap(personMap);
四、改
Integer modifyNum = personMapper.updateById(person);
五、查
Integer id=1; Person person = personMapper.selectById(id); // where id in (?,?) List<Integer> ids=new ArrayList<>(); ids.add(1); ids.add(2); List<Person> personList1 = personMapper.selectBatchIds(ids); // where name=? and age=? Map<String, Object> map = new HashMap<>(); map.put("name","linlong"); map.put("age",27); List<Person> personList2 = personMapper.selectByMap(map);
六、Wapper
Person person = new Person(); person.setName("linlong"); // UpdateWrapper<Person> updateWrapper = new UpdateWrapper<>(); QueryWrapper<Person> queryWrapper = new QueryWrapper<>(); queryWrapper.eq(!StringUtils.isEmpty(person.getName()),"name",person.getName()); List<Person> list = personMapper.selectList(queryWrapper);
七、自定义sql
mybatis-plus: mapper-locations: classpath:mapper/*.xml
@Repository public interface PersonMapper extends BaseMapper<Person> { @Select("select * from person") List<Person> findAllPerson(); }
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > <mapper namespace="com.wuxi.dao.PersonMapper"> <select id="findAllPerson" resultType="com.wuxi.bean.Person"> select * from person </select> </mapper>
八、分页插件
@EnableTransactionManagement @Configuration @MapperScan("com.wuxi.dao") public class MybatisPlusCinfig { @Bean public PaginationInterceptor paginationInterceptor(){ PaginationInterceptor paginationInterceptor = new PaginationInterceptor(); return paginationInterceptor; } }
@Repository public interface PersonMapper extends BaseMapper<Person> { @Select("select * from person") IPage<Person> findAllPerson(Page<Person> page);//分页对象必须在参数列表第一个位置，后面是查询条件参数 }
public void selectPersonPage(){ Page<Person> page = new Page<>(1,10);//参数1：查询页码；参数2：每页显示数量 IPage<Person> iPage = personMapper.findAllPerson(page); System.out.println("当前页码"+iPage.getCurrent()); System.out.println("每页显示数量"+iPage.getSize()); System.out.println("总记录数"+iPage.getTotal()); System.out.println("总页数"+iPage.getPages()); List<Person> list = iPage.getRecords(); // 数据集合 }
九、通用service
/** * Person：bean */ public interface PersonService extends IService<Person> { }
/** * PersonMapper：dao * Person：bean */ @Service @Transactional public class PersonServiceImpl extends ServiceImpl<PersonMapper,Person> implements PersonService { }