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[英]Hibernate JPA bidirectional one-to-many results with constraint violation exception
[英]JPA/Hibernate bidirectional many-to-one results in StackOverflowException
我有實體User和GrantedRole具有雙向一對多關系。
當我嘗試將GrantedRole添加到Set in User時,沒有拋出異常,但是當我調試User和GrantedRole對象的變量時,會有一個讀取的描述
com.sun.jdi.InvocationException發生了調用方法。
調試時可以讀取變量的不同字段,但是當我選擇User中的角色字段或GrantedRole中的用戶字段時,我得到與上面相同的描述。 當我進入用戶的Set of GrantedRole時,我最終找到以下描述:
詳細格式化程序錯誤:發生異常:java.lang.StackOverflowError
我的代碼:
public class User {
private Set<GrantedRole> roles = new HashSet<GrantedRole>();
public User() {
super();
}
public User(String name, String password) {
this.name = name;
this.password = password;
}
@OneToMany(fetch = FetchType.EAGER, mappedBy = "user")
public Set<GrantedRole> getRoles() {
return roles;
}
public void setRoles(Set<GrantedRole> roles) {
this.roles = roles;
}
// equals and hashCode are based on username
// toString is based on all fields
}
public class GrantedRole {
private user user;
public GrantedRole() {
super();
}
public GrantedRole(User user, Role role, Organization organization) {
this.user = user;
this.role = role;
this.organization = organization;
}
@ManyToOne
@NotNull
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
// equals and hashCode are based on all fields
// toString was based on all fields, I've changed it to not include User.
}
public class Test {
public void testStuff() {
User user = new User("name");
GrantedRole role = new GrantedRole(user, "role"); //this sets the user field
user.getRoles().add(role); //doesn't throw Exception, but debugging shows InvocationTargetException and StackOverflowException
System.out.println(user.getRoles()); //throws StackOverflowException, as I would expect
}
}
我的理解是,我應該能夠以這種方式建立雙向關系。 我閱讀了多個教程, 比如這個 ,我看不出我做的不同,導致.add(角色)出錯。
我遺漏了一些瑣碎的代碼,如果需要,我很樂意提供它。 我沒有制作代碼來確保該用戶引用具有對用戶引用的GrantedRole作為回報,但我認為這與我遇到的問題無關。
所以,我只是愚蠢,並在toString()方法中進行了遞歸調用。 User.toString()嘗試打印角色,GrantedRole.toString()嘗試打印用戶。
我通過改變GrantedRole.toString()來修復它,以打印user.getUsername(),從而打破循環。
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