直接上代码
jsp
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Insert title here</title> <link rel="stylesheet" type="text/css" href="css/css.css"> </head> <body onload="load()" > <br/><br/> <form action="" name=form1 method="post" > <div style="text-align:center; "><font size="4" face="黑体">用户名：</font> <input type="text" id='text1' name="username" value="" onchange="check1()" onmouseup="check1()" placeholder="Username"/> <br/> <input type="button" value="登录" onclick="go()" style= "height:30px;150px;background:#0066FF " onclick="show()"/> </div> </form> </body> <script> function go(){ var xmlhttp; name=document.getElementById("text1").value; if (window.XMLHttpRequest) { // IE7+, Firefox, Chrome, Opera, Safari 浏览器执行代码 xmlhttp=new XMLHttpRequest(); } else { // IE6, IE5 浏览器执行代码 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=function() { if (xmlhttp.readyState==4 && xmlhttp.status==200) { // alert(xmlhttp.responseText);//这里获取到的值为servlet反回的响应信息 take= xmlhttp.getResponseHeader('take');//获取指定Header中的值 alert(take); } } xmlhttp.open("GET","ttt?name="+name,true);//利用url传参 xmlhttp.send(); } </script> </html>
这种写法还是比较复杂的，如果结合JQury会简洁很多
servlet
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* Servlet implementation class ttt
*/
@WebServlet("/ttt")
public class ttt extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public ttt() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
request.setCharacterEncoding("UTF-8");
String name;
name=(String)request.getParameter("name");
PrintWriter out = response.getWriter();
response.setCharacterEncoding("utf-8");
response.resetBuffer();//清空原有返回信息
response.setHeader("take", "666");//添加自定义headler
out.write(name);//将name写入响应信息
out.close();
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}