Hibernate对原生sql处理及结果集报错：Expected type: java.lang.Integer, actual value: java.math.BigInteger

基于Hibernate执行sql查询方法，映射实体对象报错Expected type: java.lang.Integer, actual value: java.math.BigInteger

实体类ChannelTree

package com.han.cms.dto;

import java.math.BigInteger;

/**
 * 系统栏目树对象
 * @author Administrator
 *
 */
public class ChannelTree {
	private Integer id;
	private String name;
	private Integer pid;//映射报错，将Integer类型改成BigInteger类型即可

	public ChannelTree() {

	}

	public ChannelTree(Integer id, String name, Integer pid) {
		this.id = id;
		this.name = name;
		this.pid = pid;
	}

	public Integer getId() {
		return id;
	}

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

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Integer getPid() {
		return pid;
	}

	public void setPid(Integer pid) {
		this.pid = pid;
	}

}

service查询方法

Override
	public List getChannelTreeDatas() throws Exception{
		String sql="select c.id,c.name,IFNULL(c.pid,0) as pid from t_channel c";
		List channelTrees = this.channelDao.findListBySql(sql, ChannelTree.class, false);
		channelTrees.add(0,new ChannelTree(0,"系统栏目管理",new BigInteger("-1")));
		return channelTrees;
	}

test测试类方法

@Test
	public void getChannelTrees() throws Exception{
		System.out.println(this.channelService.getChannelTreeDatas().size());
	}

运行结果报错：

Hibernate: select c.id,c.name,IFNULL(c.pid,0) as pid from t_channel c
15:39:55,758 ERROR BasicPropertyAccessor:117 - HHH000123: IllegalArgumentException in class: com.han.cms.dto.ChannelTree, setter method of property: pid
15:39:55,760 ERROR BasicPropertyAccessor:118 - HHH000091: Expected type: java.lang.Integer, actual value: java.math.BigInteger

修改之后ChannelTree

package com.han.cms.dto;

import java.math.BigInteger;

/**
 * 系统栏目树对象
 * @author Administrator
 *
 */
public class ChannelTree {
	private Integer id;
	private String name;
	private BigInteger pid;

	public ChannelTree() {

	}
    
	public ChannelTree(Integer id, String name, BigInteger pid) {
		this.id = id;
		this.name = name;
		this.pid = pid;
	}

	public Integer getId() {
		return id;
	}

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

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public BigInteger getPid() {
		return pid;
	}

	public void setPid(BigInteger pid) {
		this.pid = pid;
	}
    
}

service查询方法

	@Override
	public List getChannelTreeDatas() throws Exception{
		String sql="select c.id,c.name,IFNULL(c.pid,0) as pid from t_channel c";
		List channelTrees = this.channelDao.findListBySql(sql, ChannelTree.class, false);
		channelTrees.add(0,new ChannelTree(0,"系统栏目管理",new BigInteger("-1")));
		return channelTrees;
	}

测试类

@Test
	public void getChannelTrees() throws Exception{
		System.out.println(this.channelService.getChannelTreeDatas().size());
	}

运行结果：

Hibernate: select c.id,c.name,IFNULL(c.pid,0) as pid from t_channel c
4

具体的解释可以参考以下的

我有一个类似下面的table(info_table)，是收集产品使用的机型信息：

id	type	model
1	nokia	xxx1
2	nokia	xxx2
3	Motorola	yyyy1
4	Motorola	yyyy2
5	Motorola	yyyy3

要实现一个前台展示的页面：

type	countType
nokia	2
Motorola	3

就这么简单的功能。相信稍微熟悉sql的人，马上就可以写出此实现。很惭愧的说，我的心里感觉很简单，由于很久没怎么深入接触sql了，也费了一番周折...

selecttype,count(*) as countType from info_table group by Type order bycountType desc

实现上面的功能。

如何放到功能（struts2.3.x,spring3.1.x,hibernate4.x）集成的环境中处理？一步一步看：

首先从dao层：

@Override
publicList getAllHandleCount(){
Sessionsession =sessionFactory.getCurrentSession();
Stringhql ="selecttype,count(*) as countType from info_table group by Type order bycountType desc";
Queryquery = session.createQuery(hql);
@SuppressWarnings("unchecked")
Listlist = query.list();
returnlist;
}

再次server层...

最后action层；

@Autowired
privateHandleCountServicehandleCountService;
privateIntegercurrentPage= 1;
privateIntegerpageSize= 10;
privateIntegertotalCount;
privateIntegertotalPage;

privateListhandleCountVO;
/*
* handle count at 2014-12-04
*
*/
publicString HandleCountQueryAll() throwsIOException{
handleCountVO=handleCountService.getAllPage(currentPage,pageSize);
totalCount=handleCountService.getAllHandleCount().size();
totalPage= (totalCount+pageSize- 1) /pageSize;
returnSUCCESS;
}
……
get/set方法

由于返回的结果不是Hibernate管理的bean，所以理所当然的想到写个VO去接纳返回结果集。

CountVO.java

publicclassCountVO {
privateString type;
privateIntegercountUser;
publicString getType(){
returntype;
}
publicvoidsetType(Stringtype){
this.type=type;
}
publicInteger getCountUser() {
returncountUser;
}
publicvoidsetCountUser(Integer countUser) {
this.countUser= countUser;
}
}

前台直接通过传递ListBean通过struts标签来实现：

xxxx.jsp

…
<s:iteratorvalues:iteratorvalue="handleCountVO">
<tr>
<td><s:propertyvalues:propertyvalue="type"/>td>
<td><s:propertyvalues:propertyvalue="countUser"/>td>
tr>
s:iterator>
…

整个流程配置完成。对我来说看似没问题，但是实际不是这样的...…

问题1：

在action层明明看到有list值，传到jsp层就是不显示，后debug跟到jsp，发现也是可以循环的，可“奇怪”的就是不显示。

经过一番折腾，才发现经过sql获得的List不是“理所当然“的List而是List