请问hibernate级联删除问题（两个字段关联）

Question

问题的描述非常简单：
  有3个东西，学校->年级->班级,问题在于删除年级时级联删除班级。
  school(主键:schoolid)，grade(主键:schoolid,gradeid),tclass(主键:schoolid,gradeid,tclassid)
  grade和tclass有点复合外健的味道，但是设置复合外健后eclipse自动生成的.hbm报错,所以我没在grade和tclass上设置外健，而是手工添加了两段。
               <set name="tclassSet" inverse="true" cascade="all">
         <key>
         <column name="schoolid"/>
         <column name="gradeid"/>
         </key>
         <one-to-many class="Tclass"/>
        </set>
                <many-to-one name="grade" class="Grade">
         <column name="schoolid"/>
         <column name="gradeid"/>
        </many-to-one>
结果加载hibernate时，配置文件出错。
详细内容请看下贴

Answer 1

--1.数据库操作
create table school (
  schoolid    int   not null,
  schoolName  varchar(50) not null,
  notes       varchar(200),
  constraint PK_SCHOOL primary key (schoolid)
);
create table grade (
  schoolid    int      not null,
  gradeid     int      not null,
  gradeName   varchar(50),
  notes       varchar(200),
  constraint PK_GRADE primary key (schoolid,gradeid)
);
create table tClass(
  schoolid    int      not null,
  gradeid     int      not null,
  tclassid     int      not null,
  tclassName   varchar(50),
  notes       varchar(200),
  constraint PK_GRADE primary key (schoolid,gradeid,tclassid)
);

alter table grade
   add constraint fk_grade_school foreign key(schoolid)
      references school(schoolid)
;
/*
alter table tClass
   add constraint fk_tclass_grade foreign key(schoolid,gradeid)
      references  grade(schoolid,gradeid)
;*/

insert into school(schoolid,schoolname,notes)values(123,'highschool','test');
insert into grade(schoolid,gradeid,gradename)values(123,234,'g1');
insert into tclass(schoolid,gradeid,tclassid,tclassname)values(123,234,345,'test');--2.hibernate配置文件（3个,school的省略,只列出grade,tclass）
--grade.hbm.xml
<?xml version="1.0" encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
                            "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
                            "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >

<!-- DO NOT EDIT: This is a generated file that is synchronized -->
<!-- by MyEclipse Hibernate tool integration.                   -->
<!-- Created Tue Dec 12 14:44:40 CST 2006                         -->
<hibernate-mapping package="model">

    <class name="Grade" table="grade">
        <composite-id name="id" class="GradeKey">
            <key-property name="gradeid" column="gradeid" type="java.lang.Integer"/>
            <key-many-to-one name="school" column="schoolid" class="School"/>
        </composite-id>
 
        <property name="gradename" column="gradeName" type="java.lang.String" />
        <property name="notes" column="notes" type="java.lang.String" />
        <set name="tclassSet" inverse="true">
         <key>
         <column name="schoolid"/>
         <column name="gradeid"/>
         </key>
         <one-to-many class="Tclass"/>
        </set>
    </class>
    
</hibernate-mapping>

--tclass.hbm.xml
<?xml version="1.0" encoding='UTF-8'?>
<!DOCTYPE hibernate-mapping PUBLIC
                            "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
                            "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >

<!-- DO NOT EDIT: This is a generated file that is synchronized -->
<!-- by MyEclipse Hibernate tool integration.                   -->
<!-- Created Tue Dec 12 14:44:44 CST 2006                         -->
<hibernate-mapping package="model">

    <class name="Tclass" table="tclass">
        <composite-id name="id" class="TclassKey">
            <key-property name="gradeid" column="gradeid" type="java.lang.Integer"/>
            <key-property name="schoolid" column="schoolid" type="java.lang.Integer"/>
            <key-property name="tclassid" column="tclassid" type="java.lang.Integer"/>
        </composite-id>
 
        <property name="tclassname" column="tclassName" type="java.lang.String" />
        <property name="notes" column="notes" type="java.lang.String" />
        <many-to-one name="grade" class="Grade">
         <column name="schoolid"/>
         <column name="gradeid"/>
        </many-to-one>
    </class>
    
</hibernate-mapping>--3.java类
--*************AbstractGrade.java*************--
package model; import java.io.Serializable;

public abstract class AbstractGrade 
    implements Serializable
{
private int hashValue = 0;
    private GradeKey id;
    private java.lang.String gradename;
    private java.lang.String notes;
    private java.util.Set tclassSet;

public java.util.Set getTclassSet() {
return tclassSet;
}

public void setTclassSet(java.util.Set tclassSet) {
this.tclassSet = tclassSet;
}

    public AbstractGrade()
    {
    }

    public AbstractGrade(GradeKey id)
    {
        this.setId(id);
    }

    public GradeKey getId()
    {
        return this.id;
    }

    public void setId(GradeKey id)
    {
        this.hashValue = 0;
        this.id = id;
    }

    public java.lang.String getGradename()
    {
        return this.gradename;
    }

    public void setGradename(java.lang.String gradename)
    {
        this.gradename = gradename;
    }

    public java.lang.String getNotes()
    {
        return this.notes;
    }
    
    public void setNotes(java.lang.String notes)
    {
        this.notes = notes;
    }
    
    public boolean equals(Object rhs)
    {
        if (rhs == null)
            return false;
        if (! (rhs instanceof Grade))
            return false;
        Grade that = (Grade) rhs;
        if (this.getId() == null || that.getId() == null)
            return false;
        return (this.getId().equals(that.getId()));
    }
    
    public int hashCode()
    {
        if (this.hashValue == 0)
        {
            int result = 17;
            if (this.getId() == null)
            {
                result = super.hashCode();
            }
            else
            {
                result = this.getId().hashCode();
            }
            this.hashValue = result;
        }
        return this.hashValue;
    }
}

--*************AbstractTclass.java*************--
package model; import java.io.Serializable;
public abstract class AbstractTclass 
    implements Serializable
{
    private int hashValue = 0;
    private TclassKey id;
    private java.lang.String tclassname;
    private java.lang.String notes;
    private Grade grade;

public Grade getGrade() {
return grade;
}

public void setGrade(Grade grade) {
this.grade = grade;
}

    public AbstractTclass()
    {
    }

    public AbstractTclass(TclassKey id)
    {
        this.setId(id);
    }

    public TclassKey getId()
    {
        return this.id;
    }

    public void setId(TclassKey id)
    {
        this.hashValue = 0;
        this.id = id;
    }

    public java.lang.String getTclassname()
    {
        return this.tclassname;
    }

    public void setTclassname(java.lang.String tclassname)
    {
        this.tclassname = tclassname;
    }

    public java.lang.String getNotes()
    {
        return this.notes;
    }

    public void setNotes(java.lang.String notes)
    {
        this.notes = notes;
    }

    public boolean equals(Object rhs)
    {
        if (rhs == null)
            return false;
        if (! (rhs instanceof Tclass))
            return false;
        Tclass that = (Tclass) rhs;
        if (this.getId() == null || that.getId() == null)
            return false;
        return (this.getId().equals(that.getId()));
    }

    public int hashCode()
    {
        if (this.hashValue == 0)
        {
            int result = 17;
            if (this.getId() == null)
            {
                result = super.hashCode();
            }
            else
            {
                result = this.getId().hashCode();
            }
            this.hashValue = result;
        }
        return this.hashValue;
    }
}

Answer 2

没搞明白为什么要用多重主键
建议用单一ID做主键，有关联的根据需要配置：<one-to-many>或者<many-to-one>

Answer 3

我用的是main()方法测试，报的是java.lang.NoClassDefFoundError
debug发现是session = HibernateUtil.currentSession();这句报的错。
实际上就是配置文件的错。

Answer 4

哪个class找不到？
是不是配置文件里面没加package名