org.apache.struts2.json.JSONWriter can not access a member of class

转自:http://www.cnblogs.com/xiaoyaorensheng/archive/2013/01/02/2842302.html

偶遇一个问题：org.apache.struts2.json.JSONWriter can not access a member of class
org.apache.tomcat.dbcp.dbcp.PoolingDataSource$PoolGuardConnectionWrapper
with modifiers "public"。困扰了半天，找到了解决方案，写写自己的一些理解。

action代码：


1 package edu.bjfu.action;
2
3 import java.util.ArrayList;
4 import java.util.List;
5
6 import javax.annotation.Resource;
7
8 import org.apache.struts2.json.annotations.JSON;
9
10
11 import com.opensymphony.xwork2.ActionSupport;
12
13 import edu.bjfu.entity.Authority;
14 import edu.bjfu.service.AuthorityService;
15
16 public class AuthoritiesAction extends ActionSupport{
17     private AuthorityService authorityService;
18     private List<Authority> authorities;
19
20     public List<Authority> getAuthorities() {
21         return authorities;
22     }
23
24     public void setAuthorities(List<Authority> authorities) {
25         this.authorities = authorities;
26     }
27     public AuthorityService getAuthorityService() {
28         return authorityService;
29     }
30
31     @Resource(name="authorityService")
32     public void setAuthorityService(AuthorityService authorityService) {
33         this.authorityService = authorityService;
34     }
35    
36     public String execute() throws Exception {
37         authorities=authorityService.getAllAuthorities();
38         return SUCCESS;
39     }
40    
41 }



配置文件代码：

1 <package name="super_admin" extends="json-default" namespace="/superadmin">
2         <action name="allAuthorities" class="edu.bjfu.action.AuthoritiesAction">
3             <result type="json"></result>
4         </action>
5 </package>
ajax交互代码：


1 $(function(){
2     $.post("superadmin/allAuthorities?dt="+new Date().getTime(),
3         function(data){
4             $("#authority").empty();
5             var json = eval(data);
6             for(var i=0;i<json.length;i++){
7                 $("#authority").append("<option value='"+json[i].authorityId+"'>"+json[i].authorityName+"</option>");
8             }
9         },"json")
10 })

这样每次在交互的时候就会发生以上错误。

主要原因：struts会将action中定义的一些变量序列化转换成json格式，需要调用对象的一系列get方法（例子中调用authorityService和authorities的get方法），并调用以上两个变量的成员变量的get方法将其内容组成json格式。但是在序列化authorityService时，由于其成员变量中含有含有接口所以会报错。

解决方案：

1）修改配置文件：指定序列化的根节点，这样data就是从authorities的根节点以下的数据，不需要用data.authorities

1     <package name="super_admin" extends="json-default" namespace="/superadmin">
2         <action name="allAuthorities" class="edu.bjfu.action.AuthoritiesAction">
3             <result type="json"><param name="root">authorities</param></result>
4         </action>
5     </package>
2) 修改java代码：让编译器不对authorityService序列化

1     @JSON(serialize=false)
2     public AuthorityService getAuthorityService() {
3         return authorityService;
4     }