Question

因此，我正在尝试为项目构建类似Twitter的外观。但是，当我尝试从数据库中提取某些数据时，出现了stackoverflow错误。我想出了这个错误，仅当我尝试使用其各自的kweet获取用户（或用户列表）时才会发生。获取以下用户可以正常工作。我的代码如下

@Entity
@Table
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "User.getByUsername", query = "SELECT u FROM User u WHERE 
u.username = :username")
,
@NamedQuery(name = "User.getByEmail", query = "SELECT u FROM User u WHERE 
u.email = :email"),
@NamedQuery(name = "User.getLogin", query = "SELECT u FROM User u WHERE 
u.password = :password AND u.email = :email")
    })
public class User implements Serializable {

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

private Role Role;

@Column
private String username;

@Column
private String password;

@Column
private String email;

private String location;
private String weburl;

@Column(length = 160)
private String bio;

@ManyToMany
private List<User> followedUsers;

@ManyToMany
private List<User> followingUsers;

@OneToMany(mappedBy = "owner", cascade = {CascadeType.DETACH, CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH}, fetch = FetchType.LAZY)
private List<Kweet> kweets;

public User() {
}

public void addFollowingUser(User user){
    followedUsers.add(user);
}
public void removeFollowingUser(User user){
    followedUsers.remove(user);
}
public void setId(Long id) {
    this.id = id;
}

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

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

public void setFollowedUsers(List<User> followedUsers) {
    this.followedUsers = followedUsers;
}

public void setFollowingUsers(List<User> followingUsers) {
    this.followingUsers = followingUsers;
}

public void setKweets(List<Kweet> kweets) {
    this.kweets = kweets;
}

public void setEmail(String email) {
    this.email = email;
}

public void setLocation(String location) {
    this.location = location;
}

public void setWeburl(String weburl) {
    this.weburl = weburl;
}

public void setBio(String bio) {
    this.bio = bio;
}

public Long getId() {
    return id;
}

public String getUsername() {
    return username;
}

public String getPassword() {
    return password;
}

@XmlTransient
public List<User> getFollowedUsers() {
    return followedUsers;
}

@XmlTransient
public List<User> getFollowingUsers() {
    return followingUsers;
}

@XmlTransient
public List<Kweet> getKweets() {
    return kweets;
}

public Role getRole() {
    return Role;
}

public String getEmail() {
    return email;
}

public String getLocation() {
    return location;
}

public String getWeburl() {
    return weburl;
}

public String getBio() {
    return bio;
}

public void addKweet(Kweet k) {
    kweets.add(k);
}

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

对于用户类（应该在其中嵌套kweet

@Entity
@Table
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "Kweet.findByText",query = "SELECT k FROM Kweet k WHERE 
k.text = :text"),
@NamedQuery(name = "Kweet.findByUId",query = "SELECT k FROM Kweet k WHERE 
k.owner.id =:id")
})
public class Kweet implements Serializable{
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;

@ManyToOne(optional = false, cascade = {CascadeType.DETACH, CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH})
private User owner;

private String username;

@OneToMany
private List<User> rekweets;

private String text;

public Kweet() {
}

public Long getId() {
    return id;
}

public User getOwner() {
    return owner;
}

public String getUsername() {
    return username;
}

@XmlTransient
public List<User> getRekweets() {
    return rekweets;
}

public String getText() {
    return text;
}

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

public void setOwner(User owner) {
    this.owner = owner;
}

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

public void setRekweets(List<User> rekweets) {
    this.rekweets = rekweets;
}

public void setText(String text) {
    this.text = text;
}

}

对于只能有一个用户的kweet类

我的问题是我在做错什么（为什么我没有得到属于用户的提示）以及如何解决这个问题

持久性无法加载特定类的数据

0 个答案: