jsp+jquery页面无刷新异步登录的一个小例子

/* * To change this template, choose Tools | Templates * and open the template in the editor. */ package net.itcast; import java.io.IOException; import java.io.PrintWriter; import java.net.URLDecoder; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * * @author xingxing */ public class UserVerify extends HttpServlet { /** * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods. * @param request servlet request * @param response servlet response */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); try { String param = request.getParameter("userName"); if (param == null || param.length() == 0) { out.println("用户名is null"); } else { String userName = URLDecoder.decode(param, "UTF-8"); if (userName.equals("wangxingkui")) { out.println("用户名[" + userName + "]已经存在，请使用别的用户名注册"); } else { out.println("可以使用用户名[" + userName + "]注册"); } } } finally { out.close(); } } // <editor-fold defaultstate="collapsed" desc="HttpServlet"> /** * Handles the HTTP <code>GET</code> method. * @param request servlet request * @param response servlet response */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } /** * Handles the HTTP <code>POST</code> method. * @param request servlet request * @param response servlet response */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } /** * Returns a short description of the servlet. */ public String getServletInfo() { return "Short description"; }// </editor-fold> }