1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <script type="text/javascript"> 10 var req; 11 function check() 12 { 13 var url ="CheckUser?uname="+ document.getElementById("uname").value; 14 if (window.XMLHttpRequest) 15 { 16 req = new XMLHttpRequest(); 17 } 18 else if (window.ActiveXObject){ 19 req = new ActiveXObject("Microsoft.XMLHTTP"); 20 } 21 req.open("GET",url, true); 22 req.onreadystatechange = show; 23 req.send(null); 24 alert("hhhh"); 25 } 26 function show(){ 27 if (req.readyState == 4) { 28 if (req.status == 200) { 29 document.getElementById("info").innerHTML=req.responseText; 30 } 31 } 32 } 33 </script> 34 <body> 35 <table> 36 <tr><td>用户名</td><td><input type="text" id="uname" ></td></tr> 37 <tr><td><input type="button" onClick="check()" value="检测用户"></td><td><div id="info"></div> </td></tr> 38 </table> 39 </body> 40 </html>
1 package javastudy; 2 3 import java.io.IOException; 4 import javax.servlet.ServletException; 5 import javax.servlet.annotation.WebServlet; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 10 /** 11 * Servlet implementation class CheckUser 12 */ 13 @WebServlet("/CheckUser") 14 public class CheckUser extends HttpServlet { 15 private static final long serialVersionUID = 1L; 16 17 /** 18 * @see HttpServlet#HttpServlet() 19 */ 20 public CheckUser() { 21 super(); 22 // TODO Auto-generated constructor stub 23 } 24 25 /** 26 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) 27 */ 28 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 29 // TODO Auto-generated method stub 30 String uname=request.getParameter("uname"); 31 String[] names={"zhang","yang","wang"}; 32 boolean flag=true; 33 for(int i =0;i<names.length;i++) 34 { 35 if(names[i].equals(uname)) 36 { 37 flag=false; 38 break; 39 } 40 41 } 42 response.setCharacterEncoding("utf-8"); 43 if(flag==false) 44 { 45 response.getWriter().println("该用户名已注册!!!"); 46 } 47 else 48 { 49 response.getWriter().println("注册成功！！！"); 50 } 51 // response.getWriter().append("Served at: ").append(request.getContextPath()); 52 } 53 54 /** 55 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) 56 */ 57 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 58 // TODO Auto-generated method stub 59 doGet(request, response); 60 } 61 62 }