java – 复杂的order-by子句到.hbm hibernate文件中

发布时间：2020-05-23 17:50:48 所属栏目：MySql 来源：互联网

导读：我有一个关于hibernate和order-by子句的问题.我有一个包含3个表的mySQL数据库：A,B和C.以下是与这些表对应的Java代码.A类代码：package database; import java.util.Set; public class A implements java.io.Serializable { private

我有一个关于hibernate和order-by子句的问题.
我有一个包含3个表的mySQL数据库：A,B和C.以下是与这些表对应的Java代码.

A类代码：

package database;

import java.util.Set;

public class A implements java.io.Serializable {

    private Integer id;
    private Set


B类代码：

package database;

public class B implements java.io.Serializable {

    private Integer id;
    private A a;
    private C c;

    public B() {
    }

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

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

    public A getA() {
        return a;
    }

    public void setA(A a) {
        this.a = a;
    }

    public C getC() {
        return c;
    }

    public void setC(C c) {
        this.c = c;
    }
}

C类代码：

package database;

public class C implements java.io.Serializable {

    private Integer id;
    private int num;

    public C() {
    }

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

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

    public int getNum() {
        return this.num;
    }

    public void setNum(int num) {
        this.num = num;
    }
}

相关的.hbm文件在这里
表A映射：


表B映射：


表C映射：


我的问题是关于A.hbm文件中的“order-by”子句.我想订购不跟随c.Id,但c.Num


不幸的是,当我这样做时,我得到以下异常：

Exception in thread "main" org.hibernate.exception.SQLGrammarException: could not initialize a collection: [database.A.listB#1]
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:92)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    at org.hibernate.loader.Loader.loadCollection(Loader.java:2069)
    at org.hibernate.loader.collection.CollectionLoader.initialize(CollectionLoader.java:62)
    at org.hibernate.persister.collection.AbstractCollectionPersister.initialize(AbstractCollectionPersister.java:628)
    at org.hibernate.event.def.DefaultInitializeCollectionEventListener.onInitializeCollection(DefaultInitializeCollectionEventListener.java:83)
    at org.hibernate.impl.SessionImpl.initializeCollection(SessionImpl.java:1853)
    at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:366)
    at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:108)
    at org.hibernate.collection.PersistentSet.iterator(PersistentSet.java:186)
    at Test.main(Test.java:36)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'listb0_.c.Num' in 'order clause'
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.Util.getInstance(Util.java:386)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1054)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4120)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4052)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2503)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2664)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2815)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
    at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2322)
    at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:1849)
    at org.hibernate.loader.Loader.doQuery(Loader.java:718)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:270)
    at org.hibernate.loader.Loader.loadCollection(Loader.java:2062)
    ... 8 more

我是hibernate的新手,我读了一些可以帮助我的标准,但是我没有看到如何将它们用于hbm文件.
谢谢你的帮助,
Lauriane
在尝试了你给我的想法后,我仍然没有答案.首先,我编写了以下方法将数据输入数据库：

private static void create() {
    A a = new A();
    HibernateUtil.save(a);

    C c1 = new C();
    c1.setNum(5);
    HibernateUtil.save(c1);

    C c2 = new C();
    c2.setNum(2);
    HibernateUtil.save(c2);

    C c3 = new C();
    c3.setNum(7);
    HibernateUtil.save(c3);

    C c4 = new C();
    c4.setNum(3);
    HibernateUtil.save(c4);

    B b1 = new B();
    b1.setA(a);
    b1.setC(c1);
    HibernateUtil.save(b1);

    B b2 = new B();
    b2.setA(a);
    b2.setC(c4);
    HibernateUtil.save(b2);

    B b3 = new B();
    b3.setA(a);
    b3.setC(c3);
    HibernateUtil.save(b3);

    B b4 = new B();
    b4.setA(a);
    b4.setC(c2);
    HibernateUtil.save(b4);

    A a2 = new A();
    HibernateUtil.save(a2);

    C c5 = new C();
    c5.setNum(13);
    HibernateUtil.save(c5);

    C c6 = new C();
    c6.setNum(11);
    HibernateUtil.save(c6);

    C c7 = new C();
    c7.setNum(10);
    HibernateUtil.save(c7);

    C c8 = new C();
    c8.setNum(14);
    HibernateUtil.save(c8);

    B b5 = new B();
    b5.setA(a2);
    b5.setC(c5);
    HibernateUtil.save(b5);

    B b6 = new B();
    b6.setA(a2);
    b6.setC(c8);
    HibernateUtil.save(b6);

    B b7 = new B();
    b7.setA(a2);
    b7.setC(c7);
    HibernateUtil.save(b7);

    B b8 = new B();
    b8.setA(a2);
    b8.setC(c6);
    HibernateUtil.save(b8);
}

它给了我2个A的实例,每个实例都有4个B实例的列表.
然后,我尝试了这段代码：
                        （编辑：安卓应用网）
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