J2EE 下各登录用户共享对象的实现源码下载

原理：设置 web.xml，使 Servlet 在项目启动时自动创建对象，各用户访问 Servlet 可实现在 Servlet 下的对象共享，再通过 Session 可将 JSP 也实现对象共享。

将要共享的对象 ShareInfo.java

/**
 * 
 */
package test;

/**
 * @author Administrator
 * 
 */
public class ShareInfo
{

  private int val = 0;

  /**
   * 
   */
  public ShareInfo()
  {
    // TODO Auto-generated constructor stub
  }

  /**
   * 累加
   */
  public void add()
  {
    val = val + 1;
  }

  /**
   * 取值
   * 
   * @return
   */
  public int getVal()
  {
    return val;
  }

}

启动时加载的 Servlet

package servlet;

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

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import test.ShareInfo;

/**
 * Servlet implementation class Info
 */
@WebServlet(name = "info", urlPatterns = { "/info" })
public class Info extends HttpServlet
{
  private static final long serialVersionUID = 1L;
  
  // 声明共享对象
  private ShareInfo shareInfo = null;

  /**
   * @see HttpServlet#HttpServlet()
   */
  public Info()
  {
    super();
    // TODO Auto-generated constructor stub
  }

  /**
   * @see Servlet#init(ServletConfig)
   */
  public void init(ServletConfig config) throws ServletException
  {
    // TODO Auto-generated method stub
    // 创建共享对象
    shareInfo = new ShareInfo();
  }

  /**
   * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
   *      response)
   */
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {
    // TODO Auto-generated method stub
    doPost(request, response); 
  }

  /**
   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
   *      response)
   */
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
  {
    // TODO Auto-generated method stub

    // 对象得到共享
    // 对象内数字累加
    shareInfo.add();

    // 存入 session,jsp 页面也将获得共享
    HttpSession httpSession = request.getSession();
    httpSession.setAttribute("INFO", shareInfo);

    processRequest(String.valueOf(shareInfo.getVal()), request, response);
  }

  /**
   * return text to explorer
   * 
   * @param strMessage
   * @param request
   * @param response
   * @throws ServletException
   * @throws IOException
   */
  protected void processRequest(String strMessage, HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException
  {
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();
    try
    {
      out.print(strMessage);
    }
    finally
    {
      out.close();
    }
  }

}

设置启动 Servlet 的 web.xml

	<servlet>
		<servlet-name>Info</servlet-name>
		<servlet-class>servlet.Info</servlet-class>
		<load-on-startup>1</load-on-startup>
	</servlet>

获得共享的 jsp

<%@page import="test.ShareInfo"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<%@ page import="test.ShareInfo"%>

<%
  ShareInfo shareInfo = null;

  Object object = session.getAttribute("INFO");
  if (object != null)
  {
    shareInfo = (ShareInfo) object;
    shareInfo.add();
  }
  else
  {
    out.print("没有找到对象，用户需要访问一次  servlet 获取 session 赋值");
    return;
  }
%>

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>GlassFish JSP Page</title>
</head>
<body>
	<%=shareInfo.getVal()%>
</body>
</html>

源码下载

http://download.csdn.net/detail/joyous/5345508

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J2EE 下各登录用户共享对象的实现 源码下载

J2EE 下各登录用户共享对象的实现源码下载