Java 使用Criteria API查询具有自引用的实体时的PropertyAccessException

我拥有以下实体：

package model.entity;

import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;

import com.fasterxml.jackson.annotation.JsonBackReference;
import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.fasterxml.jackson.annotation.JsonManagedReference;
import com.fasterxml.jackson.annotation.ObjectIdGenerators;

@Entity
@JsonIdentityInfo(generator=ObjectIdGenerators.IntSequenceGenerator.class, property="id")
public class Folder {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

    @Column
    private String title;

    @JsonBackReference
    @ManyToOne(cascade = { CascadeType.ALL }, fetch = FetchType.EAGER)
    @JoinColumn(name = "parent")
    private Folder parent;

    @JsonManagedReference
    @OneToMany(mappedBy="parent")
    private Set<Folder> children;

    @JsonManagedReference
    @OneToMany(mappedBy="containerFolder")
    private Set<Project> projects;

    @Column
    private Integer orderIndex;

    public Long getId() {
        return id;
    }

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

    public String getTitle() {
        return title;
    }

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

    public Folder getParent() {
        return parent;
    }

    public void setParent(Folder parent) {
        this.parent = parent;
    }

    public Set<Folder> getChildren() {
        return children;
    }

    public void setChildren(Set<Folder> children) {
        this.children = children;
    }

    public Set<Project> getProjects() {
        return projects;
    }

    public void setProjects(Set<Project> projects) {
        this.projects = projects;
    }

    public Integer getOrderIndex() {
        return orderIndex;
    }

    public void setOrderIndex(Integer orderIndex) {
        this.orderIndex = orderIndex;
    }



}

对于例外情况，有几种解决方案，但它们对我不起作用：

将Hibernate版本降级到4.3.5或更低版本。没用。 保留最新的Hibernate版本，但设置 hibernate.classloading.use_current_tccl_作为false的父级。也不管用。 获取根元素的第一个查询不是问题

我对此表示怀疑，因为查询试图查找所有没有ID的文件夹，而所有文件夹显然都有ID：没有ID的实体不可能存在。它实际上应该查找没有父级的实体。这将为您提供根文件夹

那你呢

criteria.add(Restrictions.eq("parent", rootFolder.getId()));

Folder类型的父级怎么可能等于Long类型的rootFolder.getId

你想要的是

criteria.add(Restrictions.eq("parent", rootFolder));

或

---

谢谢刚刚搞对了，回来删除这个问题。。。只看到它已经被回答了顺便说一句，查找家长的查询也是错误的，我已经修复了它。没有父文件夹的文件夹是根文件夹。

criteria.add(Restrictions.eq("parent", rootFolder.getId()));

criteria.add(Restrictions.eq("parent", rootFolder));

criteria.add(Restrictions.eq("parent.id", rootFolder.getId()));