您好,Hibernate 和 Jackson 有问题。有两个 POJO
@Entity
@Table(name = "USERS")
public class User implements Serializable {
static final long serialVersionUID = 4235637833262722256L;
@Id
@GeneratedValue
private int id;
@Column(name = "CREATION_DATE")
private Date creationDate;
@Column(name = "FIRST_NAME")
private String firstName;
@Column(name = "LAST_NAME")
private String lastName;
@Version
@Column(name = "VERSION")
private int version;
@Column(name = "E_MAIL")
private String email;
@Column(name = "ENABLED")
private boolean enabled;
@Column(name = "LOGIN")
private String login;
@Column(name = "PASSWORD")
private String password;
@JsonManagedReference("role")
@OneToMany(mappedBy = "user", cascade = CascadeType.ALL,fetch = FetchType.EAGER)
private Set<UserRole> userRole;
为 Spring 安全集成创建的用户及其角色。
@Entity
@Table(name = "USER_ROLES")
public class UserRole {
@Version
@Column(name = "VERSION")
int version;
@Id
@GeneratedValue
private int id;
@JsonBackReference("role")
@ManyToOne()
@JoinColumn(name = "USER_ID", referencedColumnName = "ID")
private User user;
@Column(name = "ROLE")
private String role;
并且有一个 Controller ,它通过 Jackson 由用户 Json 制作。用方法
@RequestMapping(value = "/login", method = RequestMethod.GET, produces = "application/json")
private @ResponseBody User checkLoginAvailability(@RequestParam String login) {
User user = appContext.getUserService().readUserByLogin(login);
if (user != null) {
return user;
}
return new User();
}
当此方法返回没有空字段的用户时,它会抛出:
26-Oct-2014 14:31:17.652 WARNING [http-nio-8080-exec-4]
org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.doResolveException
Handling of [org.springframework.http.converter.HttpMessageNotWritableException]
resulted Exception java.lang.IllegalStateException: Cannot call sendError() after the response has been committed
当我添加 @OneToMany(mappedBy = "user", cascade = CascadeType.ALL,fetch = FetchType.EAGER) 时出现了问题,之前它只是 fetch = FetchType.EAGER,但我无法保存用户在这种情况下,由于他的角色,表 USER_ROLE 是空的。我在 jackson 某处的无限循环中解决了这个问题,添加了一些注释 @JsonBackReference("role") 和 @JsonManagedReference("role") 但没有任何改变。我怎么解决这个问题?谢谢!
最佳答案
我建议在导致循环引用的属性上添加 @jsonignore
。这将告诉 jackson 不要序列化该属性。
关于java - hibernate 和 jackson (java.lang.IllegalStateException : Cannot call sendError() after the response has been committed),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26572245/