java突然查询不到数据,为什么无法查询到数据解决方法

为什么无法查询到数据

Java codepackage com.test.action;

import java.util.Map;

import com.opensymphony.xwork2.ActionContext;

import com.opensymphony.xwork2.ActionSupport;

import com.test.service.Iservice;

public class ListUserAction extends ActionSupport

{

private Iservice service;

public Iservice getService()

{

return service;

}

public void setService(Iservice service)

{

this.service = service;

}

@SuppressWarnings("unchecked")

@Override

public String execute() throws Exception

{

Map request = (Map) ActionContext.getContext().get("request");

request.put("list",service.listUser());

return SUCCESS;

}

}

Java code

这二段代码有问题吗？不然为什么查询不出任何数据，也没报错&#