一个json-lib.jar转换复杂对象的问题?

相关的bean如下
TVO.java代码如下

package demo;

import java.util.*;

import com.easylotto.lottobar.bean.BaseEntity;
import com.easylotto.lottobar.bean.ReqCommandVO;

public class TVO extends BaseEntity{
	private String tname;
	private List<Person> rcvoList;
	private Map map;
	
	public List<Person> getRcvoList() {
		return rcvoList;
	}

	public void setRcvoList(List<Person> rcvoList) {
		this.rcvoList = rcvoList;
	}

	public String getTname() {
		return tname;
	}

	public void setTname(String tname) {
		this.tname = tname;
	}
	

	public Map getMap() {
		return map;
	}

	public void setMap(Map map) {
		this.map = map;
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

	}

}

Person.java如下

package demo;

public class Person {
	private String name;
	private String age;
	
	public Person(String name,String age){
		this.name=name;
		this.age=age;
	}
	public String getAge() {
		return age;
	}
	public void setAge(String age) {
		this.age = age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	
}

测试类如下:

package demo;

import net.sf.json.*;
import java.util.*;

import com.easylotto.lottobar.bean.ReqCommandVO;
import com.easylotto.lottobar.bean.SocketCommandEntity;

/**
 * Json使用测试类
 * @author peidw 
 *
 */
public class JsonDemo {
	
	public String JsonStr2Object(){
		String str="{'map':{'a2':'A2','a1':'A1'},'rcvoList':[{'age':'20','name':'小裴'},{'age':'58','name':'小庞'}],'tname':'xxname'}";
		JSONObject jo=JSONObject.fromObject(str);
		TVO sce=null;
		if(jo!=null){
			sce=(TVO)jo.toBean(jo, TVO.class);
			List alist=sce.getRcvoList();
			System.out.println(alist.size());
			Person rcvo=null;
			for(int i=0;i<alist.size();i++){
				rcvo=(Person)alist.get(i);
				System.out.print(rcvo.getName()+"-"+rcvo.getAge());
			}
		}


		return "测试";
	}
	
	public void Object2JsonStr(){

		TVO tvo=new TVO();
		tvo.setTname("xxname");
		List <Person>a=new ArrayList();
		a.add(new Person("小裴","20"));
		a.add(new Person("小庞","58"));
		tvo.setRcvoList(a);
		Map map=new HashMap();
		map.put("a1", "A1");
		map.put("a2", "A2");
		tvo.setMap(map);
		JSONObject jo=JSONObject.fromObject(tvo);
		System.out.println(jo);
	}
	
	public static void main(String[] args){
		JsonDemo jd=new JsonDemo();
		jd.JsonStr2Object();
		//jd.Object2JsonStr();
	}
}

出现的异常如下
2
Exception in thread "main" java.lang.ClassCastException: net.sf.ezmorph.bean.MorphDynaBean
at demo.JsonDemo.JsonStr2Object(JsonDemo.java:26)
at demo.JsonDemo.main(JsonDemo.java:53)
使用的是json-lib-2.2.1-jdk15.jar包,请问这是怎么回事,怎么解决?

评论

1 楼 anweixiao 2008-03-07  

这个问题有两个地方值得考虑:
1、一个就是json-lib好像是使用反射实现的,那你的Person类如果没有无参数的构造方法的话，很危险;
2、在你的转化的代码上并没有告诉程序把rcvoList里的数据为何种类型

为此正确的做法是，为Person添加无参数的构造方法，同时修改代码为:

if(jo!=null){ 
             Map<String, Class> m = new HashMap<String, Class>();
             m.put("rcvoList", Person.class);
             sce=(TVO)JSONObject.toBean(jo, TVO.class, m);

这样应该就OK了…………