SSH中的Hibernate的DAO类转json时出错

 

在execute()方法的return前面将所有与DAO有关的变量设成null，就不会出错了。

 

 struts.xml:

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd"><struts><constant name="struts.objectFactory" value="spring" /><constant name="struts.i18n.encoding" value="UTF-8"/><package name="default" extends="json-default"><action name="login" class="com.whm.controller.LoginAction"><result type="json"></result></action><action name="showGoodsName" class="com.whm.controller.ShowGoodsNameAction"><result type="json"></result></action></package></struts>    

 

ShowGoodsNameAction.java

package com.whm.controller;import javax.servlet.http.HttpServletRequest;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;import com.whm.service.impl.GoodsNameService;import com.whm.service.impl.PageBean;public class ShowGoodsNameAction extends ActionSupport {/** *  */private static final long serialVersionUID = 8029696367199852252L;private GoodsNameService goodsNameService;/**第几页*/private int page;/**包含分布信息的bean*/private PageBean pageBean;/**hql查询语句*/private String hql;    public void setGoodsNameService(GoodsNameService goodsNameService){this.goodsNameService = goodsNameService;}public GoodsNameService getGoodsNameService(){return this.goodsNameService;}public int getPage(){return page;}public void setPage(int page){//若URL中无此参数,会默认为第1页this.page = page;}public PageBean getPageBean(){return pageBean;}public void setPageBean(PageBean pageBean){this.pageBean = pageBean;}public String getHql(){return this.hql;}public void setHql(String hql){this.hql=hql;}/**清理无用的变量，特别是与Hibernate关联的类，否则转化为json时会出错*/private void clearNotUsedVar(){goodsNameService=null;}@Overridepublic String execute() throws Exception{HttpServletRequest request = ServletActionContext.getRequest();int start = Integer.valueOf(request.getParameter("start"));int limit = Integer.valueOf(request.getParameter("limit"));String sort= request.getParameter("sort");//要排序的列名--无需定义，ext自动后传        String dir= request.getParameter("dir");//要排序的方式--无需定义，ext自动后传this.page=start;if(sort==null) sort="name";if(dir==null) dir="asc";this.hql="from WhmGoodsName order by "+sort+" "+dir;System.out.println("访问ShowGoodsNameAction");System.out.println("page:"+page);System.out.println("limit:"+limit);System.out.println("sort:"+sort);System.out.println("dir:"+dir);//分页的pageBean,参数pageSize表示每页显示记录数,page为当前页this.pageBean = goodsNameService.queryForPage(this.hql,limit, page);//清除，全部设成nullthis.clearNotUsedVar();return SUCCESS;}}