package?ajax;

import?java.io.IOException;
import?java.io.PrintWriter;

import?javax.servlet.ServletException;
import?javax.servlet.http.HttpServlet;
import?javax.servlet.http.HttpServletRequest;
import?javax.servlet.http.HttpServletResponse;
import?javax.servlet.http.HttpSession;

import?dao.UserDAO;
import?entity.User;

public?class?UserNameCheck?extends?HttpServlet?{

	private?UserDAO?dao?=?null;

	public?void?service（HttpServletRequest?request?HttpServletResponse?response）
			throws?ServletException?IOException?{

		request.setCharacterEncoding（“utf-8“）;
		response.setContentType（“text/html;charset=utf-8“）;
		PrintWriter?pw?=?response.getWriter（）;
		String?msg?=?null;
		//?從頁面獲得用戶名
		String?userName?=?request.getParameter（“username“）;
		this.dao?=?new?UserDAO（）;
		User?user?=?dao.findByUsername（userName）;

		if?（userName?==?null?||?userName?==?““）?{
			msg?=?“用戶名不能為空！“;
		}?else?if?（user?!=?null）?{
			msg?=?“用戶名已存在！“;

		}?else?{
			msg?=?“用戶名可以使用！“;
		}

		pw.println（msg）;
		pw.flush（）;
		pw.close（）;

	}

}

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2018-09-27?23:33??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\
?????文件?????2535093??2013-11-04?11:17??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\畢業(yè)論文.doc
?????目錄???????????0??2013-11-04?11:10??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\
?????文件?????????529??2013-04-29?14:42??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.classpath
?????目錄???????????0??2013-05-07?22:44??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.myeclipse\
?????文件?????????300??2013-11-04?11:11??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.mymetadata
?????文件????????1752??2013-04-29?14:42??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.project
?????目錄???????????0??2013-11-04?11:10??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.settings\
?????文件?????????500??2013-04-29?14:42??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.settings\.jsdtscope
?????文件??????????65??2013-04-29?14:42??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.settings\org.eclipse.core.resources.prefs
?????文件?????????364??2013-04-29?14:42??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.settings\org.eclipse.jdt.core.prefs
?????文件?????????465??2013-04-29?14:42??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.settings\org.eclipse.wst.common.component
?????文件?????????252??2013-04-29?14:42??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.settings\org.eclipse.wst.common.project.facet.core.xml
?????文件??????????49??2013-04-29?14:42??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.settings\org.eclipse.wst.jsdt.ui.superType.container
?????文件???????????6??2013-04-29?14:42??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\.settings\org.eclipse.wst.jsdt.ui.superType.name
?????目錄???????????0??2013-11-04?11:10??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\
?????目錄???????????0??2013-11-04?11:10??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\ajax\
?????文件????????1107??2013-05-24?15:57??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\ajax\UserNameCheck.java
?????文件????????1143??2013-05-07?17:18??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\ajax\ValidateServlet.java
?????目錄???????????0??2013-11-04?11:10??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\
?????文件????????1564??2013-05-05?15:19??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\HotelDAO.java
?????文件????????3097??2013-05-25?00:07??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\IndexDAO.java
?????文件????????1295??2013-05-05?17:27??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\OrderDAO.java
?????文件????????3656??2013-05-05?15:27??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\RestaurantDAO.java
?????文件????????2176??2013-05-04?22:07??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\RouteInfoDAO.java
?????文件????????3879??2013-05-07?21:25??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\ScenicSpotDAO.java
?????文件????????1202??2013-05-03?10:33??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\SpotOfRouteDAO.java
?????文件????????1142??2013-05-06?16:27??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\TouristDAO.java
?????文件????????2506??2013-05-07?21:37??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\TourRouteDAO.java
?????文件????????2185??2013-05-06?20:55??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\dao\UserDAO.java
?????目錄???????????0??2013-11-04?11:10??基于Java?Web的旅游網(wǎng)站設(shè)計(jì)與實(shí)現(xiàn)\源代碼\src\entity\
............此處省略141個文件信息