struts2 Action里直接输出 dom4j的使用

在使用Ajax与Action交互时，可以直接在Action里输出，而不是转发给JSP.struts.xml中声明action时，不再需要result标签

package com.struts2;

import java.io.PrintWriter;

import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.ServletActionContext;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;

import com.opensymphony.xwork2.ActionSupport;

public class GetXMLAction extends ActionSupport {
    private String name;
    
    public String getName() {
        return name;
    }

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

    @Override
    public String execute() throws Exception {
        // TODO Auto-generated method stub
        People people=new People();
        people.setId(1);
        people.setName("zhangsan");
        people.setAddress("beijing");
        people.setAge(20);
        
        People people2=new People();
        people2.setId(2);
        people2.setName("lisi");
        people2.setAge(30);
        people2.setAddress("Hangzhou");
        
        //下面都是dom4j的使用方法，还是挺简单的
        org.dom4j.Document document=DocumentHelper.createDocument();
        
        Element rootElement=document.addElement("persons");
        
        rootElement.addComment("This is comment!!");
        Element e=rootElement.addElement("person");
        Element idElement=e.addElement("id");
        Element nameElement=e.addElement("name");
        Element ageElement=e.addElement("age");
        Element addressElement=e.addElement("address");
        
        if(name.equals("zhangsan"))
        {
            idElement.setText(String.valueOf(people.getId()));
            nameElement.setText(people.getName());
            ageElement.setText(String.valueOf(people.getAge()));
            addressElement.setText(people.getAddress());
        }else if(name.equals("lisi"))
        {
            idElement.setText(String.valueOf(people2.getId()));
            nameElement.setText(people2.getName());
            ageElement.setText(String.valueOf(people2.getAge()));
            addressElement.setText(people2.getAddress());
        }
        
        //取HttpServletResponse对象,直接输出
        HttpServletResponse resp=ServletActionContext.getResponse();
        resp.setContentType("text/xml;charset=utf-8");
        resp.setHeader("cache-control", "no-cache");
        PrintWriter out=resp.getWriter();
        OutputFormat format=OutputFormat.createPrettyPrint();
        format.setEncoding("utf-8");
        XMLWriter writer=new XMLWriter(out, format);
        writer.write(document);
        out.flush();
        out.close();
        //返回值可以随意，因为不再判断
        return null;
    }
}