Java Spring JPA存储库合并而不是保存

你能帮我处理JPA存储库吗？在更新请求和使用POST方法期间-我只需要保存发送到我的帖子正文中的字段。但若我并没有将其写入body，那个么JPA存储库设置为null（DBMySQL，默认为null）。请看这幅画。

如果我不发送博德机场代码，更新后将变为空。但它是“UAAA”。我如何管理它？谢谢你的建议

模型等级切割：

@Entity 
@SelectBeforeUpdate 
@DynamicUpdate 
@Table(name = "airports") 
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"}) 
public class Airports {

     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private long id;
     private String airport; 
     private String code;

@RestController
public class AirportsController {
    private AirportsRepository repository;


    public AirportsController(AirportsRepository repository) {
        this.repository = repository;
    }

    @PostMapping(value = "airports/update")
    public ResponseEntity updateAirportById(@RequestBody Airports airports) {
        Airports foundedById = repository.findOne(airports.getId());
        foundedById.setAirport(airports.getAirport());
        foundedById.setCode(airports.getCode());
        repository.save(foundedById);

        return new ResponseEntity(foundedById, HttpStatus.OK);
    }

控制器类剪切：

@Entity 
@SelectBeforeUpdate 
@DynamicUpdate 
@Table(name = "airports") 
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"}) 
public class Airports {

     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     private long id;
     private String airport; 
     private String code;

@RestController
public class AirportsController {
    private AirportsRepository repository;


    public AirportsController(AirportsRepository repository) {
        this.repository = repository;
    }

    @PostMapping(value = "airports/update")
    public ResponseEntity updateAirportById(@RequestBody Airports airports) {
        Airports foundedById = repository.findOne(airports.getId());
        foundedById.setAirport(airports.getAirport());
        foundedById.setCode(airports.getCode());
        repository.save(foundedById);

        return new ResponseEntity(foundedById, HttpStatus.OK);
    }

---

这是因为您在控制器updateAirportById方法中设置了值，即使它们为null。 如果未在正文中传递“code”和“airport”的值，则getAirports方法将返回null并将其设置为foundedById，然后进行更新。简单的if条件可以解决这个问题

if(airports.getAirport() != null) 
  foundedById.setAirport(airports.getAirport());

---

对于“code”

调用

save（）

也会将null作为列

code

上的默认值保留。仅更新给定字段需要预加载或其他查询。这就是问题所在。不会的，因为他在第一行从数据库中获取记录。所以，如果他没有用null更新值，它将有自己的值，它真的在工作！谢谢拉法索卡尔斯基！祝你今天愉快，兄弟！！