Struts2 Jquery 实现Ajax无刷新验证用户名是否存在

package com.hisoft.jqt.action; import java.io.IOException; import java.io.PrintWriter; import java.util.HashMap; import java.util.Map; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import net.sf.json.JSONObject; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.ActionContext; import com.opensymphony.xwork2.ActionSupport; @SuppressWarnings("serial") public class TestAction extends ActionSupport{ HttpServletRequest hsr; String result; public HttpServletRequest getHsr() { return hsr; } public void setHsr(HttpServletRequest hsr) { this.hsr = hsr; } public String getResult() { return result; } public void setResult(String result) { this.result = result; } public String test() throws IOException{ Map<String, String> map = new HashMap<String, String>(); ActionContext ac = ActionContext.getContext(); HttpServletRequest req = (HttpServletRequest)ac.get(ServletActionContext.HTTP_REQUEST); HttpServletResponse res = (HttpServletResponse)ac.get(ServletActionContext.HTTP_RESPONSE); String userName = req.getParameter("userName"); map.put("userName", userName); System.out.println(userName); System.out.println("---------test()---------"); res.setContentType("text/html;charset=UTF-8"); PrintWriter w = res.getWriter(); if("jack".equals(userName)){ // 将要返回的map对象进行json处理 JSONObject jo = JSONObject.fromObject(map); System.out.println("进入了....."); // 调用json对象的toString方法转换为字符串然后赋值给result this.result = jo.toString(); w.println("用户名已经存在"); }else{ w.println("用户名不存在"); } w.close(); return "success"; } }