对单表而言的composite-id使用方法

hbm

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping SYSTEM "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd" >
<hibernate-mapping>
   <class name="com.dsii.hibernate.po.UserRole" table="role_user"  >
	
		<composite-id class="com.dsii.hibernate.po.UserRoleID" name="userRoleID">
			<key-property name="userNo" column="user_id" type="string"/> 
			<key-property name="roleNo" column="role_id" type="string"/> 
		</composite-id>
	
		<property name="notes" column="notes"/>
		
   </class>
</hibernate-mapping>

ID

package com.dsii.hibernate.po;

import java.io.Serializable;

import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;

/**
 * <p>Title：UserRoleID.java</p>
 * <p>Description：</p>
 * <p>Copyright：Copyright (c); 2004 DSII,Inc</p>
 * <p>Company：DSII,Inc</p>
 * @author　Jason  2004-8-3
 * @version　1.0
 */
public class UserRoleID implements Serializable {

	private String userNo;
	private String roleNo;

	public String getRoleNo(); {
		return roleNo;
	}

	public String getUserNo(); {
		return userNo;
	}

	public void setRoleNo(String string); {
		roleNo = string;
	}

	public void setUserNo(String string); {
		userNo = string;
	}

	public boolean equals(Object other); {
		if (!(other instanceof UserRoleID););
			return false;
		UserRoleID castOther = (UserRoleID); other;
		return new EqualsBuilder();
			.append(this, castOther);
			.append(userNo, castOther.userNo);
			.append(roleNo, castOther.roleNo);
			.isEquals();;
	}

	public int hashCode(); {
		return new HashCodeBuilder();.append(userNo);.append(roleNo);.toHashCode();;
	}
}

PO

package com.dsii.hibernate.po;

/**
 * <p>Title：UserRole.java</p>
 * <p>Description：</p>
 * <p>Copyright：Copyright (c); 2004 DSII,Inc</p>
 * <p>Company：DSII,Inc</p>
 * @author　Jason  2004-8-3
 * @version　1.0
 */
public class UserRole {
	
	private UserRoleID userRoleID;
	private String notes;
	

	public String getNotes(); {
		return notes;
	}

	public UserRoleID getUserRoleID(); {
		return userRoleID;
	}

	public void setNotes(String string); {
		notes = string;
	}

	public void setUserRoleID(UserRoleID roleID); {
		userRoleID = roleID;
	}

}

main

package com.dsii.hibernate.po;

import net.sf.hibernate.HibernateException;

import com.dsii.common.hibernate.HibernateUtil;

/**
 * <p>Title：UserRoleTest.java</p>
 * <p>Description：</p>
 * <p>Copyright：Copyright (c); 2004 DSII,Inc</p>
 * <p>Company：DSII,Inc</p>
 * @author　Jason  2004-8-3
 * @version　1.0
 */
public class UserRoleTest {

	public static void main(String[] args); {
		UserRoleID userRoleID = new UserRoleID();;
		userRoleID.setUserNo("u001");;
		userRoleID.setRoleNo("r001");;

		UserRole userRole = new UserRole();;
		userRole.setUserRoleID(userRoleID);;
		userRole.setNotes("notes");;

		try {
			HibernateUtil.add(userRole);;
		} catch (HibernateException e); {
			e.printStackTrace();;
		}

		try {
			userRoleID = new UserRoleID();;
			userRoleID.setUserNo("u001");;
			userRoleID.setRoleNo("r001");;
			userRole =
				(UserRole); HibernateUtil.findById(
					UserRole.class,userRoleID);;
			System.out.println("..............:" + userRole.getNotes(););;
		} catch (HibernateException e); {
			e.printStackTrace();;
		}

	}
}

DDL
Table    Name：role_user
Column Name：role_id,user_id,notes，都为字符串类型的就OK了

Good Luck.

对多表关连而言的composite-id使用方法
只要将hbm中的composite-id改为

		<composite-id class="com.dsii.hibernate.po.UserRoleID" name="userRoleID" >
			<key-many-to-one name="user" class="com.dsii.hibernate.po.User" column="user_id"/>
			<key-many-to-one name="role" class="com.dsii.hibernate.po.Role" column="role_id"/>
		</composite-id>

再把UserRoleID.java中的两个field改为User,Role型的就可以了

Good Luck.

谢谢！
请问

HibernateUtil.findById();
HibernateUtil.add();

是什么作用?add是save()吗？findById()呢？排序吗？

HibernateUtil.add()其实就是Session.save(Object obj);
HibernateUtil.findById()其实就是Session.load(Class clazz,Serializable pk) ;
这种单笔查询就不用排序了吧

楼上的，问一个问题，你提出的例子只说明了如何进行保存（insert/update）和查询（select），那么如何进行删除呢，尤其是，当复合主键的一个字段是另外一个表的外键时，应该怎么处理呢？