java比较保存的实体

Question

我正在保存一些实体，这是我从REST-API获得的。我用的是春季JPA回购协议。保存时，我会为每个实体生成一个id。sanveAndFlush（）方法只监视实体的id是否已经存在，然后不会再次保存。但我的问题是，我生成I id，然后在保存时它只是复制实体。我该如何与其他实体进行比较，比如文本或类似的东西

客房服务：

public void saveOrUpdate(Tweetpost tweetpost) {
        tweetRepository.saveAndFlush(tweetpost);
    }

Tweetpost实体：

    @Id
    @GeneratedValue
    @Column(columnDefinition = "INT unsigned")
    private Integer id;

    @Column(columnDefinition = "LONG")
    private long tweetid;

    @NotEmpty
    @Length(max = 255)
    @Column(columnDefinition = "VARCHAR(255)", length = 255, nullable = false)
    private String profileImageUrl;

    @NotEmpty
    @Length(max = 64)
    @Column(columnDefinition = "VARCHAR(64)", length = 64, nullable = false)
    private String fromUser;

    @NotEmpty
    @Column(columnDefinition = "TEXT", nullable = false)
    private String unmodifiedText;

    @NotNull
    @Column(columnDefinition = "DATE", nullable = false)
    private Date createdAt;

    @Length(max = 255)
    @Column(columnDefinition = "VARCHAR(255)", length = 255, nullable = false)
    private String url;

    @Length(max = 255)
    @Column(columnDefinition = "VARCHAR(255)", length = 255, nullable = false)
    private String displayUrl;

    @Length(max = 255)
    @Column(columnDefinition = "VARCHAR(255)", length = 255, nullable = false)
    private String expandedUrl;

    @Length(max = 255)
    @Column(columnDefinition = "VARCHAR(255)", length = 255, nullable = false)
    private String mediaUrl;

Answer 1

请试试这个

@GeneratedValue(strategy=GenerationType.IDENTITY)
private Integer id;