java ajax web 网页聊天室

package com.jtkj.action; import java.io.PrintWriter; import javax.faces.application.Application; import javax.servlet.ServletContext; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionSupport; public class ChuLiAction extends ActionSupport { private static final long serialVersionUID = 1L; @Override public String execute() throws Exception { HttpServletRequest request = ServletActionContext.getRequest(); HttpServletResponse response = ServletActionContext.getResponse(); response.setContentType("text/xml;charset=UTF-8"); response.setHeader("Cache-Control", "no-cache"); PrintWriter out = response.getWriter(); StringBuffer sb = new StringBuffer(); String content = java.net.URLDecoder.decode(request .getParameter("content"), "UTF-8");//聊天内容 String username=(String)request.getSession().getAttribute("userinfo"); String content_1=username+"说:"+content+"\r\n"; //HttpSession session = (HttpSession) request.getSession(); //ServletContext application = (ServletContext) session.getServletContext(); if(""!=content && null!=content){ ServletActionContext.getServletContext().setAttribute("app_flag","true"); String timp=(String)ServletActionContext.getServletContext().getAttribute("suoYou_content"); if(timp!="null" && timp!=null){ ServletActionContext.getServletContext().setAttribute("suoYou_content",timp+content_1); }else{ ServletActionContext.getServletContext().setAttribute("suoYou_content",content_1); } } //out.print(sb.toString()); //out.close(); return "success"; } }