servlet:
package com.servlet;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.*;
public class Hi extends HttpServlet {
public void doGet(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{
response.setContentType("text/html;charset=utf-8");
response.getWriter().write("alert");
/*PrintWriter out =response.getWriter();
out.print("hi");
String name=request.getParameter("name");
String pwd = request.getParameter("pwd");
out.print(name);
out.print(pwd);
if(name.equals("name") && pwd.equals("pwd")){
out.print("print");
request.getRequestDispatcher("NewFile.jsp").forward(request,response);
}
out.flush();
out.close();*/
}
public void doPost(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{
response.setContentType("text/html;charset=utf-8");
response.getWriter().write("alert");
/*PrintWriter out =response.getWriter();
out.print("hi");
String name=request.getParameter("name");
String pwd = request.getParameter("pwd");
out.print(name);
out.print(pwd);
if(name.equals("name") && pwd.equals("pwd")){
out.print("print");
request.getRequestDispatcher("NewFile.jsp").forward(request,response);
}
out.flush();
out.close();*/
}
}
ajax:
var xmlHttp = false;
function createXMLHttpRequest(){
if(window.ActiveObject){
xmlHttp = new ActiveXObject("Msxml2.XMLHTTP.3.0");
}else if(window.XMLHttpRequest){
xmlHttp = new XMLHttpRequest();
}
}
function startRequest(){
// alert("alert");
createXMLHttpRequest();
xmlHttp.onreadystatechange= handleStateChange;
// var name= document.getElementById("name").value();
<%String path =request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
xmlHttp.open("POST","http://localhost:8087/myfirstproject/front/Hi", true);
xmlHttp.send();
}
function handleStateChange(){
if(xmlHttp.readyState == 4){
if(xmlHttp.status == 200){
alert("alert!!!!!!");
document.getElementById("result").innerHTML = xmlHttp.responseText;
}else{
alert("请求的页面有错误！");
}
}
原文：https://www.cnblogs.com/broadencoder/p/12403544.html