JQuery用户名校验的具体实现

$.get("http://localhost:8080/JQueryStudy/UserVerify?userName=" + encodeURI(encodeURI(userName)),null,          function(response){            $("#result").html(response);          }        )

/* * To change this template, choose Tools | Templates * and open the template in the editor. */package com.linying;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;/** * 用户名验证Servlet * @author Ying-er * @time 2010-4-25下午08:02:08 * @version 1.0 */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("用户名不能为空");      } else {        String userName = URLDecoder.decode(param, "UTF-8");        System.out.println(userName);        if (userName.equals("Ying-er")) {          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>}