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我正在尝试在 java 应用程序中使用 hibernate 从数据库中获取角色。我正在为此进行多对多映射。

获取数据后，它将从数据库中删除。我也没有调用 delete 方法，仍然会发生删除。

角色.java

@Entity
@Table(name = "ROLE") 
public class Role extends BaseModel implements java.io.Serializable {

private Long id;
private Set<User> users = new HashSet<User>(0); 


@Id
@Column(name = "ID", unique = true, nullable = false, scale = 0)
public Long getId() {
    return this.id;
}

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


@ManyToMany(fetch = FetchType.LAZY, mappedBy = "roles")
@JoinTable(name = "USERROLEMAP", joinColumns = { @JoinColumn(name = "ROLEID", nullable = false, updatable = false) }, inverseJoinColumns = { @JoinColumn(name = "USERID", nullable = false, updatable = false) })
public Set<User> getUsers() {
    return this.users;
}

public void setUsers(Set<User> users) {
    this.users = users;
}

}

用户.java

@Cacheable
@Entity
@Table(name = "USER", uniqueConstraints = @UniqueConstraint(columnNames = "LOGINID"))
public class User extends BaseModel implements java.io.Serializable {

private Long id;

private Set<Role> roles = new HashSet<Role>(0);


@Id
@Column(name = "ID", unique = true, nullable = false, scale = 0)
public Long getId() {
    return this.id;
}

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


@ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JoinTable(name = "USERROLEMAP", joinColumns = { @JoinColumn(name = "USERID", nullable = false, updatable = false) }, inverseJoinColumns = { @JoinColumn(name = "ROLEID", nullable = false, updatable = false) })
public Set<Role> getRoles() {
    return this.roles;
}

}

我们正在尝试使用以下代码片段从数据库中获取角色

public List<String> rolesAsGA() {
    List<String> proxyUserRoles = new ArrayList<String>();
    Iterator<Role> itr = getRoles().iterator();
    while (itr.hasNext()) {
        proxyUserRoles.add(new SimpleGrantedAuthority(itr.next()
                .getRoleName()));
    }
    return proxyUserRoles;
}

获取角色后，数据（相应角色）同时被删除，谁能告诉我为什么？

编辑 -我们在 eclipse 中调试，hibernate 将集合标记为删除，因为集合实体的 currentPersistor 变为 null。将进一步调试并发布任何更新。

编辑 1我们错过了提及，用户是 @Cacheable，并且正在从 ehcache 中获取，当进行 getRole 调用时，集合被加载，然后及时排队等待删除。删除 @Cacheable 注释可以解决问题。我是否会创建一个关于 @Cacheable 和 manytomany 的单独问题，或者我是否应该更新这个问题并希望得到适当的解决方案？

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1 回答 1

0

我想这导致了一个问题

private Set<Role> roles = new HashSet<Role>(0);

@ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JoinTable(name = "USERROLEMAP", joinColumns = { @JoinColumn(name = "USERID", nullable = false, updatable = false) }, inverseJoinColumns = { @JoinColumn(name = "ROLEID", nullable = false, updatable = false) })
public Set<Role> getRoles() {
    return this.roles;
}

它应该是

 private Set<Role> roles;

@ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JoinTable(name = "USERROLEMAP", joinColumns = { @JoinColumn(name = "USERID", nullable = false, updatable = false) }, inverseJoinColumns = { @JoinColumn(name = "ROLEID", nullable = false, updatable = false) })
public Set<Role> getRoles() {
    if(roles == null){
         return new HashSet<Role>;
    }
    return this.roles;
}

因为每当调用 getRoles 时，它总是会返回一个空集。所以休眠假设您实际上已经清空/删除了集合并在数据库中删除它们

于 2013-07-15T05:52:47.087 回答