找到了两个相同集合hibernate异常的表示

Question

我有一个Spring MVC应用程序来处理可以托管一个或多个用户的用户和结构。 我使用Hibernate来保持持久性，并且我对用户和结构之间的一对多关系存在一些问题。

这是我的用户模型：

@Entity
@Table(name="USERS")
public class User extends DatabaseEntity {

@Id @GeneratedValue
private Long id = 0L;

@Column
@NotEmpty
private String firstName;

@Column
private String lastName;

@Column
private Date birthDate;

@Column
private String nation;

@Column
private String town;

@Column
private String idNumber;

@Column(unique = true)
private String email;

@Column String resetPasswordToken = "";

@Column
private String password;

@Column
private String avatarUrl;

@Column @Enumerated(EnumType.STRING)
private Role role;

@ManyToOne
@JoinColumn(name = "STRUCTURE_ID")
@Cascade({CascadeType.DETACH})
private Structure structure;

public enum Role {
    ADMINISTRATOR,
    SPECIALIST,
    PATIENT,
    DOCTOR,
    CARE_GIVER
}

public User() {
    birthDate = new Date();
}

public Long getId() {
    return id;
}

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

public String getFirstName() {
    return firstName;
}

public void setFirstName(String firstName) {
    this.firstName = firstName;
}

public String getLastName() {
    return lastName;
}

public void setLastName(String lastName) {
    this.lastName = lastName;
}

public Date getBirthDate() {
    return birthDate;
}

public void setBirthDate(Date birthDate) {
    this.birthDate = birthDate;
}

public String getNation() {
    return nation;
}

public void setNation(String nation) {
    this.nation = nation;
}

public String getTown() {
    return town;
}

public void setTown(String town) {
    this.town = town;
}

public String getIdNumber() {
    return idNumber;
}

public void setIdNumber(String idNumber) {
    this.idNumber = idNumber;
}

public String getEmail() {
    return email;
}

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

public String getAvatarUrl() {
    return avatarUrl;
}

public void setAvatarUrl(String avatarUrl) {
    this.avatarUrl = avatarUrl;
}

public Role getRole() {
    return role;
}

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

public Set<Group> getGroups() {
    return null;
}

public void setGroups(Set<Group> groups) {

}

public Set<Group> getCreatedGroups() {
    return null;
}

public void setCreatedGroups(Set<Group> createdGroups) {

}

public String getPassword() {
    return password;
}

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

public Set<HangoutUser> getHangoutUsers() {
    return null;
}

public void setHangoutUsers(Set<HangoutUser> hangoutUsers) {

}

public String getResetPasswordToken() {
    return resetPasswordToken;
}

public void setResetPasswordToken(String resetPasswordToken) {
    this.resetPasswordToken = resetPasswordToken;
}

public Group getStructure() {
    return structure;
}

public void setStructure(Structure structure) {
    this.structure = structure;
}

@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (!(o instanceof User)) return false;

    User user = (User) o;

    if (!email.equals(user.email)) return false;
    if (!id.equals(user.id)) return false;

    return true;
}

@Override
public int hashCode() {
    Long res = id;
    if(id == null)
        res = 0L;

    int result = res.hashCode();
    result = 31 * result + email.hashCode();
    return result;
}
}

这是我的结构模型：

@Entity
@Table(name = "STRUCTURES")
public class Structure extends DatabaseEntity {

@Id @GeneratedValue
Long id = 0L;

@Column
String name;

@Column
String address;

@Column
String city;

@Column
String state;

@OneToMany(mappedBy = "structure", fetch = FetchType.EAGER)
@Cascade({CascadeType.DELETE})
Set<User> users = new HashSet<User>();

public Long getId()
{
    return id;
}

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

public String getName()
{
    return name;
}

public void setName(String name)
{
    this.name = name;
}

public String getAddress()
{
    return address;
}

public void setAddress(String address)
{
    this.address = address;
}

public String getCity()
{
    return city;
}

public void setCity(String city)
{
    this.city = city;
}

public String getState()
{
    return state;
}

public void setState(String state)
{
    this.state = state;
}

public Set<User> getUsers()
{
    return this.users;
}

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

我的问题是，当我尝试查找所有评估值为STRUCTURE_ID的用户时，我得到一个Hibernate Exception，如下所示：

org.springframework.orm.hibernate3.HibernateSystemException：找到同一集合的两个表示：it.amtservices.livinglab.model.Group.users;嵌套异常是org.hibernate.HibernateException：找到了两个相同集合的表示：it.amtservices.livinglab.model.Structure.users     在org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException（SessionFactoryUtils.java:690）...

我该怎么做才能解决这个问题？我已经尝试了很多方法，但没有解决。

我粘贴了UsersRepository和StructureRepository的抽象存储库实现：

@Transactional
public abstract class AbstractRepository<Model extends DatabaseEntity>
{
Logger logger = Logger.getLogger(this.getClass().getSimpleName());

@PersistenceContext
EntityManager em;

protected Class<Model> ModelClass;

protected List<Model> findBy(String parameterName, Object parameterValue)
{
    Query q = em.createQuery("select t from " + ModelClass.getSimpleName() + " t where t." + parameterName + " = :" + parameterName);
    q.setParameter(parameterName, parameterValue);

    List<Model> results = null;

    try
    {
        results = q.getResultList();
    }
    catch (Exception e)
    {
        return null;
    }

    return results;
}

protected List<Model> findBy(Map<String, Object> parameters)
{
    String whereClause = "";
    for (String key : parameters.keySet())
    {
        if (!whereClause.equals("")) whereClause += " and ";

        whereClause += "t." + key + " = :" + key;
    }

    Query q = null;

    try
    {
        q = em.createQuery("select t from " + ModelClass.getSimpleName() + " t where " + whereClause);
    }
    catch (Exception e)
    {
        e.printStackTrace();
    }

    for (String key : parameters.keySet())
    {
        q.setParameter(key, parameters.get(key));
    }

    List<Model> results = null;

    try
    {
        results = q.getResultList();
    }
    catch (Exception e)
    {
        return null;
    }

    return results;
}

protected Model findOneBy(String parameterName, Object parameterValue)
{
    List<Model> results = findBy(parameterName, parameterValue);

    if (results != null && results.size() > 0) return results.get(0);

    return null;
}

protected Model findOneBy(Map<String, Object> parameters)
{
    List<Model> results = findBy(parameters);

    if (results != null && results.size() > 0) return results.get(0);

    return null;
}

public Model findOne(Long id)
{
    return findOneBy("id", id);
}

public List<Model> findAll()
{
    Query q = em.createQuery("select t from " + ModelClass.getSimpleName() + " t");
    List<Model> results = null;

    try
    {
        results = q.getResultList();
    }
    catch (Exception e)
    {
        return null;
    }

    return results;
}

public boolean save(Model model)
{
    try
    {
        Model newModel = em.merge(model);
        if (model.getId() == 0L) model.setId(newModel.getId());
    }
    catch (Exception e)
    {
        logger.error(ModelClass.getSimpleName() + "Repository: " + e.getMessage());

        return false;
    }

    return true;
}

public void save(List<Model> models)
{
    for (Model model : models)
    {
        save(model);
    }
}

public void delete(Model model)
{
    delete(model.getId());
}

public void delete(Long id)
{
    beforeDelete(findOne(id));

    try
    {
        Query q = em.createQuery("delete from " + ModelClass.getSimpleName() + " t where t.id = :id").setParameter("id", id);
        q.executeUpdate();
    }
    catch (Exception e)
    {
        logger.error(ModelClass.getSimpleName() + "Repository: " + e.getMessage());
    }
}

public void delete(Collection<Model> models)
{
    for (Model model : models)
    {
        delete(model.getId());
    }
}

public void deleteAll()
{
    for (Model model : findAll())
    {
        delete(model);
    }
}

public abstract void beforeDelete(Model model);

public List<Model> find(List<Long> ids)
{
    List<Model> models = new ArrayList<Model>();

    for (Long id : ids)
    {
        Model model = findOne(id);

        if (model != null) models.add(model);
    }

    return models;
}
}

谢谢！