Java 保存数据时休眠TransientPropertyValueException

我正在尝试使用hibernate将数据插入数据库。下面是我将如何执行该操作

    session.beginTransaction();
    pojo.StuDetails stu = new StuDetails();
    stu.setFName(f_name);
    stu.setLName(l_name);
    stu.setSex(sex);
    stu.setDob(dob);

    pojo.Subject sub = new Subject(subject, day, time);
    pojo.SubjectHasStuDetails shs = new SubjectHasStuDetails(stu, sub);

    session.save(shs);
    session.getTransaction().commit();  

但这给了我一个错误的说法

线程“main”中出现异常 org.hibernate.TransientPropertyValueException:非空属性 引用瞬态值-必须先保存瞬态实例，然后 当前操作

这是我的学生资料

 public class StuDetails  implements java.io.Serializable {


 private Integer id;
 private String FName;
 private String LName;
 private String sex;
 private String dob;
 private Set subjectHasStuDetailses = new HashSet();
 ...
 //constructors and getters, setters

My StudentDetails hbm.xml

<hibernate-mapping>
    <class name="pojo.StuDetails" table="stu_details" catalog="laravel_test" optimistic-lock="version">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="identity" />
        </id>
        <property name="FName" type="string">
            <column name="f_name" length="45" not-null="true" />
        </property>
        <property name="LName" type="string">
            <column name="l_name" length="45" not-null="true" />
        </property>
        <property name="sex" type="string">
            <column name="sex" length="45" not-null="true" />
        </property>
        <property name="dob" type="string">
            <column name="dob" length="45" not-null="true" />
        </property>
        <set name="subjectHasStuDetailses" table="subject_has_stu_details" inverse="true" lazy="true" fetch="select">
            <key>
                <column name="stu_details_id" not-null="true" />
            </key>
            <one-to-many class="pojo.SubjectHasStuDetails" />
        </set>
    </class>
</hibernate-mapping>

Subject.hbm.xml

<hibernate-mapping>
    <class name="pojo.Subject" table="subject" catalog="laravel_test" optimistic-lock="version">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="identity" />
        </id>
        <property name="subName" type="string">
            <column name="sub_name" length="45" not-null="true" />
        </property>
        <property name="day" type="string">
            <column name="day" length="45" not-null="true" />
        </property>
        <property name="time" type="string">
            <column name="time" length="45" not-null="true" />
        </property>
        <set name="subjectHasStuDetailses" table="subject_has_stu_details" inverse="true" lazy="true" fetch="select">
            <key>
                <column name="subject_id" not-null="true" />
            </key>
            <one-to-many class="pojo.SubjectHasStuDetails" />
        </set>

    </class>
</hibernate-mapping>

subjecthastudetials.hbm.xml

<hibernate-mapping>
    <class name="pojo.SubjectHasStuDetails" table="subject_has_stu_details" 
           catalog="laravel_test" optimistic-lock="version">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="identity" />
        </id>
        <many-to-one name="stuDetails" class="pojo.StuDetails" fetch="select">
            <column name="stu_details_id" not-null="true" />
        </many-to-one>
        <many-to-one name="subject" class="pojo.Subject" fetch="select" >
            <column name="subject_id" not-null="true" />
        </many-to-one>
    </class>
</hibernate-mapping>

---

有人能帮我解决这个错误吗。。。谢谢..

在您的

主题hastudials.hbm.xml中进行以下更改：

<many-to-one name="stuDetails" class="pojo.StuDetails" fetch="select" cascade="all">
            <column name="stu_details_id" not-null="true" />
        </many-to-one>
<many-to-one name="subject" class="pojo.Subject" fetch="select" cascade="all" >
            <column name="subject_id" not-null="true" />
        </many-to-one>



将
cascade=“all”属性添加到
stuDetails
和
subject
多对一标记中


当我们应用关系时，级联属性是必需的
在对象之间，级联属性传输对一个对象执行的操作
将对象复制到其相关子对象上
如果我们编写
cascade=“all”
，那么父类对象上的更改将
如果我们写cascade=“all”，也会影响子类对象
然后在父对象上执行插入、删除、更新等所有操作
对子对象也有影响
示例：如果我们对父级应用插入（或更新或删除）操作
类对象，则子类对象也将存储到
数据库
是的。成功了。非常感谢你。但我有一个问题。为什么cascade=“all”仅在subjecthastudetials.hbm.xml中？？？
<hibernate-mapping>
    <class name="pojo.SubjectHasStuDetails" table="subject_has_stu_details" 
           catalog="laravel_test" optimistic-lock="version">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="identity" />
        </id>
        <many-to-one name="stuDetails" class="pojo.StuDetails" fetch="select">
            <column name="stu_details_id" not-null="true" />
        </many-to-one>
        <many-to-one name="subject" class="pojo.Subject" fetch="select" >
            <column name="subject_id" not-null="true" />
        </many-to-one>
    </class>
</hibernate-mapping>

<many-to-one name="stuDetails" class="pojo.StuDetails" fetch="select" cascade="all">
            <column name="stu_details_id" not-null="true" />
        </many-to-one>
<many-to-one name="subject" class="pojo.Subject" fetch="select" cascade="all" >
            <column name="subject_id" not-null="true" />
        </many-to-one>