Question

我刚刚将OpenJPA从版本1.2更新到2.2，并且我的许多JUnit都失败了。其中大多数是因为ManyToOne关系改变了行为。假设我们有两个实体

package org.my;

import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.ManyToOne;

@Entity
public class Many {

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    private One one;

    public One getOne() {
        return one;
    }

    public void setOne(One one) {
        this.one = one;
    }

}

和

package org.my;

import java.util.List;

@Entity
public class One {
    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "one")
    private List<Many> many;

    public List<Many> getMany() {
        return many;
    }

    public void setMany(List<Many> many) {
        this.many = many;
    }

}

当我创建一个对象并将其设置为List of Many时，除了持久化和提交之外，我得到了这样的异常

org.apache.openjpa.persistence.InvalidStateException: The field "one" of instance "org.my.Many@4d9cfefb" contained a null value; the metadata for this field specifies that nulls are illegal.

我以为OpenJPA cat找到一个对象并把它放到Many.one字段中，我错了吗？如果不是我怎么能实现这个目标？

Answer 1

一个对象的列表中的每个很多对象在保存之前应首先 setOne

将OpenJPA从1.2升级到2.2后，OpenJPA + Derby ManyToOne问题

1 个答案: