Hibernate，双向更新

Question

我试图用hibernate在2个表(User和UserRole)中更新具有多个角色的用户记录。当我保存时，它正常工作，但是，当我尝试更新时，如果对象包含存储在数据库中的角色，它就会失败。我没有找到一个很好的答案，但我猜它不能直接用方法"更新"，双向应该我在更新中手动实现不是吗?我遵循Spring Security对用户的结构。

这是我的User类:

@Entity
@Table(name = "users", schema = "cmsdb")
public class User {
private String username;
private String password;
private boolean enabled;
private Set<UserRole> userRole = new HashSet<UserRole>(0);
public User() {
}
public User(String username, String password, boolean enabled) {
    this.username = username;
    this.password = password;
    this.enabled = enabled;
}
public User(String username, String password, 
    boolean enabled, Set<UserRole> userRole) {
    this.username = username;
    this.password = password;
    this.enabled = enabled;
    this.userRole = userRole;
}
@Id
@Column(name = "username", unique = true, nullable = false, length = 45)
public String getUsername() {
    return username;
}
public void setUsername(String username) {
    this.username = username;
}
@Column(name = "password", nullable = false, length = 60)
public String getPassword() {
    return password;
}
public void setPassword(String password) {
    this.password = password;
}
@Column(name = "enabled", nullable = false)
public boolean isEnabled() {
    return enabled;
}
public void setEnabled(boolean enabled) {
    this.enabled = enabled;
}
@OneToMany(fetch = FetchType.EAGER, mappedBy = "user")  //,cascade = {CascadeType.ALL}
@Cascade({CascadeType.SAVE_UPDATE,CascadeType.DELETE})
@OnDelete(action = OnDeleteAction.CASCADE)
public Set<UserRole> getUserRole() {
    return userRole;
}
public void setUserRole(Set<UserRole> userRole) {
    this.userRole = userRole;
}
}

这是我的UserRole类:

@Entity
@Table(name = "user_roles", schema = "cmsdb", 
uniqueConstraints = @UniqueConstraint(
    columnNames = { "role", "username" }))
public class UserRole {
private Integer userRoleId;
private User user;
@ValidRole
private String role;
public UserRole () {
}
public UserRole(User user, String role) {
    this.user = user;
    this.role = role;
}
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "user_role_id", 
    unique = true, nullable = false)
public Integer getUserRoleId() {
    return userRoleId;
}
public void setUserRoleId(Integer userRoleId) {
    this.userRoleId = userRoleId;
}
@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "username", nullable = false)
public User getUser() {
    return user;
}
public void setUser(User user) {
    this.user = user;
}
@Column(name = "role", nullable = false, length = 45)
public String getRole() {
    return role;
}
public void setRole(String role) {
    this.role = role;
}
public String toString () {
    return role;
}
@Override
public int hashCode() {
    return userRoleId;
}
@Override
public boolean equals(Object obj) {
    UserRole role = (UserRole) obj;
    return (userRoleId == role.getUserRoleId());
}
}

这些是我的DAO方法:

// IT WORKS PROPERLY
@Override
@Transactional
public boolean createUser(User user) {
    String hashedPassword = passwordEncoder.encode(user.getPassword());
    user.setPassword(hashedPassword);
    Set<UserRole> roles = new HashSet<UserRole> ();
    for(UserRole role: user.getUserRole()) {
        roles.add(new UserRole(user,role.getRole()));   
    }
    user.setUserRole(roles);
    sessionFactory.getCurrentSession().save(user);
    return true;
}
// It doesn't work if it tries to update an User with an UserRole stored in the UserRole table in the database
@Override
@Transactional
public boolean updateUser(User user) {
// Get user by id
    User userpersis = (User) getSessionFactory().getCurrentSession().load(User.class, user.getUsername());
  // Primary key shouldn't be modified
  userpersis.setEnabled(user.isEnabled());
  userpersis.getUserRole().retainAll( user.getUserRole() );
  userpersis.getUserRole().addAll( user.getUserRole() );
  sessionFactory.getCurrentSession().update(userpersis);
  return true;
}

错误是:

WARN : org.hibernate.engine.jdbc.spi.SqlExceptionHelper - SQL Error: 1062, SQLState: 23000
ERROR: org.hibernate.engine.jdbc.spi.SqlExceptionHelper - Duplicate entry  'ROLE_MAINTENANCE-asdf' for key 'uni_username_role'
WARN : org.hibernate.engine.jdbc.spi.SqlExceptionHelper - SQL Warning Code: 1062, SQLState: 23000 ...

Answer 1

在User中，将orphanRemoval加入级联:

@Cascade(cascade={CascadeType.ALL}, orphanRemoval=true)
@OnDelete(action = OnDeleteAction.CASCADE)
public Set<UserRole> getUserRole() { ...

(参见JPA 2.0的orphanRemoval=true VS on delete Cascade)

然后，代替

Set<UserRole> roles = new HashSet<UserRole> ();
// Guess for roles, should be needed to load them also from the db
for(UserRole role : user.getUserRole()) {
    roles.add(new UserRole(userpersis,role.getRole())); 
}
userpersis.setUserRole(roles);

试

userpersis.getUserRole().clear(); // Let Hibernate know that we're really removing all the references
for(UserRole role : user.getUserRole()) {
    userpersis.getUserRole().add(new UserRole(userpersis,role.getRole())); 
}

尽管事实上，您可能甚至不想删除所有userrole，然后插入所有新数据。你也可以这样写

userpersis.getUserRole().retainAll( user.getUserRole() );
userpersis.getUserRole().addAll( user.getUserRole() );

但是，这要求您在UserRole中实现equals()和hashCode()。

编辑:当然不工作时，在您的情况下，user的角色对象不能与userpersis的角色对象相同，因为反向引用到拥有的对象。