Hibernate配置联合主键（内部类实现主键）

public class A{

   private A.id id;
   private String bar;


   public static class Id{

      private String a;
      private String b;

     //重写eqauls和hashcode方法
     //getter，setter
  }

   //getter，setter

}

   映射文件:

  <hibernate-mapping package="org.xx.yyy.zzzz">

	<!--
		Depends on Hibernate configuration with hibernate.hbm2ddl.auto=update.
	-->

	<class name="A" table="TA">
	    <composite-id name="id" class="XmlSchemaGrant$Id">
            <key-property name="a" type="string">
                <column name="a" />
            </key-property>
            <key-property name="b" type="string">
                <column name="b" />
            </key-property>
        </composite-id>
		 
		<property name="bar" column="bar" type="text"
			  not-null="false" />
	 
	</class>

   注意Java类中，Id类必须是静态类，否则会报No default constructor for entity的错误。

   注意配置文件中，配置联合主键的class中间要用$符号。

 

   关于静态内部类，其相当于写在Java文件中的普通类。可参考以下文字：

  http://java.sun.com/docs/books/jls/third_edition/html/classes.html#8.1.3

https://forum.hibernate.org/viewtopic.php?f=1&t=973414&view=previous

 写道

Check out this section of the Java language spec that explains the difference between static and non-static inner classes:
http://java.sun.com/docs/books/jls/third_edition/html/classes.html#8.1.3

A static inner class is conceptually no different than a regular general class declared in a .java file.