myservlet.java

防止一个用户多次登陆

package com.servlet;

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;

public class MyServlet extends HttpServlet {

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

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

		response.setContentType("text/html;charset=UTF-8");
		PrintWriter out = response.getWriter();
		
		String t1 = request.getParameter("t1");
		request.getSession().setAttribute("session",t1);
		out.println(t1);
		
		
		out.println("<a href='show.jsp'>查看在线人数</a>");
		
		out.flush();
		out.close();
	}

}