使用ajax向服务器发送请求
<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Insert title here</title><script type="text/javascript" src="js/jquery-1.8.3.min.js" ></script><script type="text/javascript">//页面加载完成后$(function(){$("#username").blur(function(){var usernamevalue = $("#username").val();//alert(usernamevalue)var url = "/jquery_ajax/load";$.ajax({url:url,data:{'username':usernamevalue},type:"post",dataType:"html",success:function(data){$("#username_span").html(data);}});});});</script></head><body><input type="text" name="username" id="username" /><span id="username_span"></span><br /></body></html>
服务端java代码编写
package com.niwotaxuexiba.servlet;import java.io.IOException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class LoadServlet extends HttpServlet {public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException{//解决乱码问题response.setContentType("text/html;charset=utf-8");//得到用户名String username = request.getParameter("username");//判断用户名是否可用if(("tom").equals(username)){//用户名不可以使用response.getWriter().write("用户名被占用");}else{//用户名可以使用response.getWriter().write("用户名可以使用");}}public void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException{doGet(request,response);}}
web.xml配置
<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="/2001/XMLSchema-instance" xmlns="/xml/ns/javaee" xsi:schemaLocation="/xml/ns/javaee /xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"><display-name>jquery_ajax</display-name><welcome-file-list><welcome-file>index.html</welcome-file><welcome-file>index.htm</welcome-file><welcome-file>index.jsp</welcome-file><welcome-file>default.html</welcome-file><welcome-file>default.htm</welcome-file><welcome-file>default.jsp</welcome-file></welcome-file-list><servlet><display-name>LoadServlet</display-name><servlet-name>LoadServlet</servlet-name><servlet-class>com.niwotaxuexiba.servlet.LoadServlet</servlet-class></servlet><servlet-mapping><servlet-name>LoadServlet</servlet-name><url-pattern>/load</url-pattern></servlet-mapping></web-app>
