Servlet端
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {System.out.println("Checkuserservlet");//接收ajax提交的数据//getParameter("uname");uname来自 这里下面// xmlHttpRequest.open("GET","/ajax/check?uname="+uname,true);为这里的check?uname=‘name’String uname = request.getParameter("uname");System.out.println(uname);//假定用户名为king,就不可用,其他用户名可以response.setContentType("text/html;charset=utf-8");if ("king".equals(uname)){//不能使用king用户名User king= new User(100,"king","king@sohu.com","666");//把king转成json字符串String strKing = new Gson().toJson(king);//返回response.getWriter().write(strKing);}else {//如果用户名可以用,返回“ ”response.getWriter().write("");}}}
用ajax传验证username
出现一下错误
点击open library setting
发现gson-jar包没有进入artifact
修好网络状态200 ajax状态2