一個事物下jpa更新數據庫實體對象屬性後自動update

記錄今天偶然發現的一個隱藏的bug

具體是這樣的：在一個事物中查詢出一條記錄例如Student id=1,然後修改student對象的一個屬性例如name,再通過jpa執行update 語句修改一個字段age 例如：update student set age = 1 where id=1。最後發現數據庫中除了age更新之外，name字段也做了更新，一條update 指令執行了兩次update。測試代碼如下

service

@Service
@Transactional(readOnly = true)
public class LabelConfigService {

    private ISysLabelConfigRepository iSysLabelConfigRepository;


    @Autowired
    public LabelConfigService(ISysLabelConfigRepository iSysLabelConfigRepository){
        this.iSysLabelConfigRepository = iSysLabelConfigRepository;
     
    }

    @Transactional
    public void testUpdate() {
        SysLabelConfig labelConfig = iSysLabelConfigRepository.findOne(2637);
        labelConfig.setRemark("wlllllllllllll");
        //即使不執行下面的update labelConfig依然會update
        iSysLabelConfigRepository.updateSource(labelConfig.getId(),12);
    }

}

repository

public interface ISysLabelConfigRepository extends JpaRepository<SysLabelConfig,Integer>
        ,JpaSpecificationExecutor<SysLabelConfig> {

    @Modifying
    @Query("update SysLabelConfig set source=?2 where id=?1")
    void updateSource(Integer id, Integer source);
}

test

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = ApplicationBootstrap.class)
@WebAppConfiguration
public class TestSysLabelConfig {

    @Autowired
    private LabelConfigService labelConfigService;


    @Test
    public void testUpdate(){
        labelConfigService.testUpdate();

    }



}

執行sql如下

0:24:16.495 [main] INFO  c.c.j.m.s.s.TestSysLabelConfig - Started TestSysLabelConfig in 23.558 seconds (JVM running for 25.682)
Hibernate: select syslabelco0_.id as id1_17_0_, syslabelco0_.create_time as create_t2_17_0_, syslabelco0_.creator as creator3_17_0_, syslabelco0_.label_category as label_ca4_17_0_, syslabelco0_.label_name as label_na5_17_0_, syslabelco0_.label_sub_category as label_su6_17_0_, syslabelco0_.remark as remark7_17_0_, syslabelco0_.source as source8_17_0_ from sys_label_config syslabelco0_ where syslabelco0_.id=?
Hibernate: update sys_label_config set label_category=?, label_name=?, label_sub_category=?, remark=?, source=? where id=?
Hibernate: update sys_label_config set source=? where id=?

實際上即使不執行update語句，修改後的數據庫實體對象也會自動更新！！！

解決方法

1.在事物下不要修改實體對象的屬性

2.將事物放在repository的接口方法上

ps:在事物中對實體對象的操作要小心，最好不要修改實體對象的屬性或者將實體對象轉換爲vo對象再進行進一步的操作