precheckservlet.java

ajax工程的小例子

/**
 * Created on Jul 11, 2007
 * By Maxwell C. Dong
 * 
 * Copyright 2006-2007 the original author or authors.
 */
package com.tarena.ajax.servlet;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.tarena.ajax.service.IUserRegisterService;

/**
 * User for verify the username
 * 
 * @author maxwell conrad
 *
 */
public class PreCheckServlet extends AbstractServlet{

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("text/xml;charset=UTF-8");
		response.setHeader("Cache-Control", "no-cache");
		String username = (String)request.getParameter("username");
		String xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";
		
		if(username == null || "".equals(username)) {
			xml += "<message><info>Username is required !</info></message>";
		}  else if(isContain(username)) {
			xml += "<message><info>The username has exsites,Please choose other username!</info></message>";
		} else {
			xml += "<message><info>it is valid user</info></message>";
		}
		
		response.getWriter().write(xml);
	}

	public void doPost(HttpServletRequest arg0, HttpServletResponse arg1) throws ServletException, IOException {
		doGet(arg0, arg1);
	}
	
	private boolean isContain(String username){
		IUserRegisterService service = (IUserRegisterService) this.getService("userRegisterService");
		List list = service.queryDBvalidateUserRegister(username);
		if(list != null && !list.isEmpty()) {
			return true;
		} 
		return false;		
	}
}