一个老问题:could not initialize a collection: XXX

[victorn]

org.apache.jasper.JasperException: could not initialize a collection: [com.coolgo.domain.model.Topic.posts#1]
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:510)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
com.coolgo.util.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:91)

一张board表,一张topic表,一张post表
board表 与 topic表 为双向一对多关系
topic表 与 post表 为双向一对多关系

Board.hbm.xml

<hibernate-mapping>
    <class name="com.coolgo.domain.model.Board" table="board" catalog="coolgo">
        <id name="boardId" type="java.lang.Integer">
            <column name="board_id" />
            <generator class="identity" />
        </id>
        <property name="boardIsMother" type="java.lang.String">
            <column name="board_isMother" length="6" />
        </property>
        <property name="boardBid" type="java.lang.Integer">
            <column name="board_bid" />
        </property>
        <property name="boardName" type="java.lang.String">
            <column name="board_name" length="300" />
        </property>  
        ........
        <set 
	  name="topics" 
	  cascade="all" 		   
	  inverse="true" 
	  lazy="false" >
	   <key column="topic_boardid"/> 
	   <one-to-many class="com.coolgo.domain.model.Topic"/> 
	</set>
    </class>
</hibernate-mapping>

Topic.hbm.xml

<hibernate-mapping>
    <class name="com.coolgo.domain.model.Topic" table="topic" catalog="coolgo">
        <id name="topicId" type="java.lang.Integer">
            <column name="topic_id" />
            <generator class="identity" />
        </id>        
        <property name="topicUser" type="java.lang.String">
            <column name="topic_user" length="300" />
        </property>
        <property name="topicName" type="java.lang.String">
            <column name="topic_name" length="300" />
        </property>
 	.....        
        <many-to-one name="board"
        column="topic_boardid"
        class="com.coolgo.domain.model.Board"
        lazy="false"
        not-null="true"></many-to-one>
         <set 
	   name="posts" 
	   cascade="all"
	   inverse="true" 
	   lazy="false">
	    <key column="post_topicid"/> 
	    <one-to-many class="com.coolgo.domain.model.Post"/> 
	 </set>    </class>
</hibernate-mapping>

Post.hbm.xml

<hibernate-mapping>
    <class name="com.coolgo.domain.model.Post" table="post" catalog="coolgo">
        <id name="postId" type="java.lang.Integer">
            <column name="post_id" />
            <generator class="identity" />
        </id>
        <property name="postBoardid" type="java.lang.Integer">
            <column name="post_boardid" />
        </property>
        <property name="postUser" type="java.lang.String">
            <column name="post_user" length="300" />
        </property>
        .........
        
        <many-to-one name="topic"
        column="post_topicid"
        class="com.coolgo.domain.model.Topic" 
        lazy="false"
        not-null="true"></many-to-one>
    </class>
</hibernate-mapping>

Board.java

public class Board implements java.io.Serializable {	
	private Integer boardId;	
	private Integer boardBid = 0;
	private String boardName;
	private String boardInfo;
	private Set topics = new HashSet();
	....

	public Set getTopics() {
		return topics;
	}

	public void setTopics(Set topics) {
		this.topics = topics;
	}
	....
}

Topic.java

public class Topic implements java.io.Serializable {
	private Integer topicId;
//	private Integer topicBoardid;
	private String topicUser;
	private String topicName;	
	....
	private Board board;
	private Set posts = new HashSet();	

	public Board getBoard() {
		return board;
	}
	public void setBoard(Board board) {
		this.board = board;
	}
	public Set getPosts() {
		return posts;
	}
	public void setPosts(Set posts) {
		this.posts = posts;
	}
	....
}

Post.java

public class Post implements java.io.Serializable {
	private Integer postId;
	private Integer postBoardid;
	private String postUser;
	private Topic topic;
        ......
	public Topic getTopic() {
		return topic;
	}

	public void setTopic(Topic topic) {
		this.topic = topic;
	}
}

注意在 Topic.hbm.xml 中红色代码,没有添加时,测试一切正常.然而添加后,java测试正常,而web测试却出现了:

could not initialize a collection: [com.coolgo.domain.model.Topic.posts#1] 这样的错误.

又当红色代码中 lazy="false" 改为 lazy="true" 时,web测试正常,而java测试出现:
Exception in thread "main" org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.coolgo.domain.model.Topic.posts, no session or session was closed
.....
为什么呢?(测试均为查找测试)

[开跑车的猪]

我觉得好象是你的那个private Set posts = new HashSet();这句话有问题吧，你把这个set集合给改一下看看

[victorn]

噢,试试1楼的.
2楼的我也要试试,不过觉得应该不会啊,我在Board.java中也设置了 private Set topics = new HashSet();但不会出错,
照理应 private Set posts = new HashSet(); 该不会错啊. 试试看.

[mysoko]

把你hibernate代码贴出来。

[临远]

LazyInitializationException:

懒惰加载错误，用OpenSessioninView呗

[victorn]

package com.coolgo.domain.dao;

import java.util.Date;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.LockMode;
import org.hibernate.Query;
import org.hibernate.criterion.Example;

import com.coolgo.domain.model.Post;

/**
 * A data access object (DAO) providing persistence and search support for Post
 * entities. Transaction control of the save(), update() and delete() operations
 * can directly support Spring container-managed transactions or they can be
 * augmented to handle user-managed Spring transactions. Each of these methods
 * provides additional information for how to configure it for the desired type
 * of transaction control.
 * 
 * @see com.coolgo.domain.model.Post
 * @author MyEclipse Persistence Tools
 */

public class PostDAO extends BaseHibernateDAO {
	private static final Log log = LogFactory.getLog(PostDAO.class);
	// property constants
	public static final String POST_BOARDID = "postBoardid";
	public static final String POST_USER = "postUser";
	public static final String POST_TOPICID = "postTopicid";
	public static final String POST_REPLYID = "postReplyid";
	public static final String POST_CONTENT = "postContent";
	public static final String POST_IP = "postIp";

	public void save(Post transientInstance) {
		log.debug("saving Post instance");
		try {
			getSession().save(transientInstance);
			log.debug("save successful");
		} catch (RuntimeException re) {
			log.error("save failed", re);
			throw re;
		}
	}

	public void delete(Post persistentInstance) {
		log.debug("deleting Post instance");
		try {
			getSession().delete(persistentInstance);
			log.debug("delete successful");
		} catch (RuntimeException re) {
			log.error("delete failed", re);
			throw re;
		}
	}

	public Post findById(java.lang.Integer id) {
		log.debug("getting Post instance with id: " + id);
		try {
			Post instance = (Post) getSession().get(
					"com.coolgo.domain.model.Post", id);
			return instance;
		} catch (RuntimeException re) {
			log.error("get failed", re);
			throw re;
		}
	}

	public List findByExample(Post instance) {
		log.debug("finding Post instance by example");
		try {
			List results = getSession().createCriteria(
					"com.coolgo.domain.model.Post").add(Example.create(instance))
					.list();
			log.debug("find by example successful, result size: "
					+ results.size());
			return results;
		} catch (RuntimeException re) {
			log.error("find by example failed", re);
			throw re;
		}
	}

	public List findByProperty(String propertyName, Object value) {
		log.debug("finding Post instance with property: " + propertyName
				+ ", value: " + value);
		try {
			String queryString = "from Post as model where model."
					+ propertyName + "= ?";
			Query queryObject = getSession().createQuery(queryString);
			queryObject.setParameter(0, value);
			return queryObject.list();
		} catch (RuntimeException re) {
			log.error("find by property name failed", re);
			throw re;
		}
	}

	public List findByPostBoardid(Object postBoardid) {
		return findByProperty(POST_BOARDID, postBoardid);
	}

	public List findByPostUser(Object postUser) {
		return findByProperty(POST_USER, postUser);
	}

	public List findByPostTopicid(Object postTopicid) {
		return findByProperty(POST_TOPICID, postTopicid);
	}

	public List findByPostReplyid(Object postReplyid) {
		return findByProperty(POST_REPLYID, postReplyid);
	}

	public List findByPostContent(Object postContent) {
		return findByProperty(POST_CONTENT, postContent);
	}

	public List findByPostIp(Object postIp) {
		return findByProperty(POST_IP, postIp);
	}

	public List findAll() {
		log.debug("finding all Post instances");
		try {
			String queryString = "from Post";
			Query queryObject = getSession().createQuery(queryString);
			return queryObject.list();
		} catch (RuntimeException re) {
			log.error("find all failed", re);
			throw re;
		}
	}

	public Post merge(Post detachedInstance) {
		log.debug("merging Post instance");
		try {
			Post result = (Post) getSession().merge(detachedInstance);
			log.debug("merge successful");
			return result;
		} catch (RuntimeException re) {
			log.error("merge failed", re);
			throw re;
		}
	}

	public void attachDirty(Post instance) {
		log.debug("attaching dirty Post instance");
		try {
			getSession().saveOrUpdate(instance);
			log.debug("attach successful");
		} catch (RuntimeException re) {
			log.error("attach failed", re);
			throw re;
		}
	}

	public void attachClean(Post instance) {
		log.debug("attaching clean Post instance");
		try {
			getSession().lock(instance, LockMode.NONE);
			log.debug("attach successful");
		} catch (RuntimeException re) {
			log.error("attach failed", re);
			throw re;
		}
	}
}

是这个吗?

[thblx]

大哥，你这个问题解决没有啊？我的怎么也找不到原因啊