杰克逊序列化期间,子对象为空?

时间:2012-02-24 04:35:30

标签: json serialization annotations parent-child jackson

我捕获了json响应,我发现它是{“page”:“1”,“total”:“2”,“records”:“15”,“rows”:[{“id”:1 “名字”: “约翰”, “姓氏”: “史密斯”, “用户名”: “约翰”, “密码”: “21232f297a57a5a743894a0e4a801fc3”, “角色”:空},{ “ID”:2, “名字” : “简”, “姓氏”: “亚当斯”, “用户名”: “简”, “密码”: “ee11cbb19052e40b07aac0ca060c23ee”, “角色”:空},

我的用户和角色类非常简单,所以我认为我必须忽视一些微不足道的事情。

@Entity(name="user")
public class User implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    private String firstName;
    private String lastName;

    @Column(unique=true)
    private String username;
    private String password;

    @JsonIgnore
    @OneToMany(mappedBy="user", cascade={CascadeType.PERSIST, CascadeType.MERGE},fetch =FetchType.EAGER)
    private List<Role> roles =  new ArrayList<Role>();


    public List<Role> getRoles() {
        return roles;
    }

    public void setRoles(List<Role> roles) {
        this.roles = roles;
    }


    @ManyToOne
    private Role role;

    public User() {}

    public User(String username, String password, String firstName, String lastName, Role role) {
        this.username = username;
        this.password = password;
        this.firstName = firstName;
        this.lastName = lastName;
        this.role = role;
    }

    public User(String username, String firstName, String lastName, Role role) {
        this.username = username;
        this.firstName = firstName;
        this.lastName = lastName;
        this.role = role;
    }

    public User(String username) {
        this.username = username;
    }

    public Long getId() {
        return id;
    }

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

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public Role getRole() {
        return role;
    }

    public void setRole(Role role) {
        this.role = role;
    }
}

@Entity(name="role")
public class Role  implements Serializable{

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @JsonIgnore
    @ManyToOne
    @JoinColumn (name = "user_id", nullable= true)
    private User user;
    private Integer role;

    public Role() {}

    public Role(Integer role) {
        this.role = role;
    }

    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public User getUser() {
        return user;
    }
    public void setUser(User user) {
        this.user = user;
    }
    public Integer getRole() {
        return role;
    }
    public void setRole(Integer role) {
        this.role = role;
    }
}

我也尝试了

  

@JsonUnwrapped @ManyToOne私人角色角色;

但这更糟糕,因为在这种情况下我的json根本没有角色。     { “ID”:1, “名字”: “约翰”, “姓氏”: “史密斯”, “用户名”: “约翰”, “密码”: “21232f297a57a5a743894a0e4a801fc3”},

1 个答案:

答案 0 :(得分:0)

由于复杂的遗留关系要求(即用户具有角色和角色),我在将对象作为响应传回之前错误地操作了对象。

@JsonUnwrapped只能在子对象中有属性时解包,因此它按预期工作。