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java - JPA 实体的 equals 和 hashcode 中应该包含什么

转载 作者：塔克拉玛干 更新时间：2023-11-02 19:57:30 26 4
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在创建 JPA 实体方面，什么应该和不应该进入 equals 和 hashcode。例如，我有一个地址实体，如下所示。

我读到不应包含 ID，但不确定原因。在我的例子中，像 State 这样的嵌套对象呢？我没有包括位置，因为状态是非拥有端，位置拥有关系。

在下面的类中，equals 和 hashcode 中应该和不应该包含什么？

@Entity
@Table(name = "T_ADDRESS")
@XmlRootElement
@EqualsAndHashCode(exclude = {"id", "locations"})
@ToString(exclude = {"location"})
public class Address implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "addressSeq")
    @SequenceGenerator(name = "addressSeq", sequenceName = "T_ADDRESS_SEQ", allocationSize = 1)
    @Column(name = "ID")
    private Long id;

    @Size(max = 255)
    @Column(name = "STREET_LINE_1")
    private String streetLine1;

    @Size(max = 255)
    @Column(name = "STREET_LINE_2")
    private String streetLine2;

    @NotBlank
    @Size(max = 255)
    @Column(name = "CITY")
    private String city;

    @ManyToOne(fetch = FetchType.EAGER, optional = false)
    @JoinColumn(name = "STATE_ID", referencedColumnName = "ID")
    private State state;

    @NotBlank
    @Size(max = 10)
    @Column(name = "POSTAL_CODE")
    private String postalCode;

    // Referenced Properties
    @OneToMany(fetch = FetchType.LAZY, mappedBy = "address")
    private List<Location> locations;

    public Address() {
    }

    public Address(String streetLine1, String streetLine2, String city, State state, String postalCode) {
        this.streetLine1 = streetLine1;
        this.streetLine2 = streetLine2;
        this.city = city;
        this.state = state;
        this.postalCode = postalCode;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getStreetLine1() {
        return streetLine1;
    }

    public void setStreetLine1(String streetLine1) {
        this.streetLine1 = streetLine1;
    }

    public String getStreetLine2() {
        return streetLine2;
    }

    public void setStreetLine2(String streetLine2) {
        this.streetLine2 = streetLine2;
    }

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public State getState() {
        return state;
    }

    public void setState(State state) {
        this.state = state;
    }

    public String getPostalCode() {
        return postalCode;
    }

    public void setPostalCode(String postalCode) {
        this.postalCode = postalCode;
    }

    public List<Location> getLocations() {
        return locations;
    }

    public void setLocations(List<Location> locations) {
        this.locations = locations;
    }
}

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