用ajax验证用户名是否可以注册 POST方式

来源：互联网发布：淘宝退货运费险怎么退编辑：程序博客网时间：2024/05/16 05:34

registerpost.jsp 这里注意与GET方式不同的地方

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>POST方式，检查用户名是否 可以注册</title></head><body><input id="usernameID" type="text" name="username"><span id="tipID"></span>  <script type="text/javascript">document.getElementById("usernameID").onblur = function(){var username = this.value;//创建ajax对象var ajax = new XMLHttpRequest();var method = "POST";var url = "${pageContext.request.contextPath}/AjaxRegisterServlet";ajax.open(method,url);var content = "username="+username;//POST方式提交的一定要这行，会将请求体的汉子进行UTF-8编码ajax.setRequestHeader("content-type","application/x-www-form-urlencoded");ajax.send(content);//------------------数据已发送  ajax.onreadystatechange = function(){if(ajax.readyState == 4){if(ajax.status == 200){var tip = ajax.responseText;document.getElementById("tipID").innerHTML = tip; }}}}</script></body></html>

服务端

protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {request.setCharacterEncoding("UTF-8");response.setContentType("text/html;charset=UTF-8");String username = request.getParameter("username");System.out.println(username);String tip = "";if("杰克".equals(username)){tip = "用户名已经存在";}else{tip = "可以注册";}PrintWriter pw = response.getWriter();pw.write(tip);pw.flush();pw.close();}

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