JavaEE小练习-----------留言板

import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.Date;


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


public class ChatServlet extends HttpServlet {


	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);
	}


	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setContentType("text/html;charset=utf-8");
		PrintWriter out = response.getWriter();
		out.println("");
		out.println("");
		out.println("  ");
		out.println("  ");


		//获取留言
		request.setCharacterEncoding("utf-8");
		//留言者的信息: ip, time
		String ip = request.getRemoteAddr();
		SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");
		String time = sdf.format(new Date());
		
		//留言
		String msg = request.getParameter("msg");
		String msgs = (String) getServletContext().getAttribute("msgs");
		if(msg!=null && !msg.trim().equals("")){
			msg = time+"  "+ip+": "+msg;
			if(msgs==null){
				msgs = msg;
			}else{
				msgs = msgs +"
"+ msg;
			}
			getServletContext().setAttribute("msgs", msgs);
			//out.println(msgs);
		}
		if(msgs!=null){
			String div="
"+msgs+"
";
			out.println(div);
		}
		
		out.println("
");
		//留言提交的表单
		String form ="
" +
					"留言:"+
					""+
				"
";
		out.println(form);
		out.println("  ");
		out.println("");
		out.flush();
		out.close();
	}


}