Ajax uses the original ecology JS to verify that the username exists _javascript skill

Directly on the code:
Reg_ajax.html

<! DOCTYPE html>  

The

requested servlet code is as follows, Userservlet.java

Package cn.bestchance.servlet;
Import java.io.IOException;

Import java.util.ArrayList;
Import javax.servlet.ServletException;
Import Javax.servlet.annotation.WebServlet;
Import Javax.servlet.http.HttpServlet;
Import Javax.servlet.http.HttpServletRequest;

Import Javax.servlet.http.HttpServletResponse; /** * Servlet Implementation class Userservlet/@WebServlet ("/userservlet") public class Userservlet extends HTTPSERVL


  Et {private static final long serialversionuid = 1L;
    protected void doget (HttpServletRequest request, httpservletresponse response) throws Servletexception, IOException {
  DoPost (request, response); /** * @see Httpservlet#dopost (httpservletrequest request, httpservletresponse response) * * protected void DoP OST (HttpServletRequest request, httpservletresponse response) throws Servletexception, IOException {String username=r
    Equest.getparameter ("username"); This uses ArrayList instead of querying data from the database arraylist<string> userlist =new ARRAYLIST&LT
    String> ();
    Userlist.add ("admin");
    Userlist.add ("test");
    Userlist.add ("chance");
    Verify that the username exists Boolean flag = false;
        for (String string:userlist) {if (String.Equals (username)) {flag = true;
      Break
    } if (flag) {//user name already exists response.getwriter (). Print ("yes");
    }else{//user name does not exist Response.getwriter (). Print ("no");


 }
  }

}

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