在此之前也看了很多同一帐号异地登录的，有的是采用后登录者必须等待前登录者释放后才可以登录，我的项目中要用到想qq那样可以踢出，我具体的做法如下：

LoginServelt.java 做登录使用

OnlineUserListener.java 做session超时清理工作

LogValidata.java 做权限验证

logout.jsp做退出

LoginServelt.java public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{

HttpSession session=request.getSession();

String username=request.getParameter("username");

String password=request.getParameter("password");

ServletContext sc=this.getServletContext();

String sessionId=session.getId();

String path= request.getContextPath();

Map onlineUserMap=(Map)sc.getAttribute("onlineUserMap");

//如果是首个用户登录，onlineUserMap为空，new一个

if(onlineUserMap==null){

onlineUserMap=new HashMap();

}

if(username!=null || password!=null){

onlineUserMap.put(username.trim(), sessionId);

sc.setAttribute("onlineUserMap",onlineUserMap);

//设置username,因为这个唯一的，作为key

session.setAttribute("username", username);

response.sendRedirect(path+"/success.jsp");

}else{

response.sendRedirect(path+"/index.jsp");

}

}

OnlineUserListener.java

public class OnlineUserListener implements HttpSessionListener {

public void sessionCreated(HttpSessionEvent event) {

}

public void sessionDestroyed(HttpSessionEvent event) {

HttpSession session = event.getSession();

Map onlineUserMap=(Map)session.getServletContext().getAttribute("onlineUserMap");

if(onlineUserMap!=null){

onlineUserMap.remove(session.getId());

session.getServletContext().setAttribute("onlineUserMap", onlineUserMap);

}

}

}

LogValidata.java

public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException {

HttpServletRequest request=(HttpServletRequest)arg0;

HttpServletResponse response=(HttpServletResponse)arg1;

ServletContext sc=request.getSession().getServletContext();

String username=(String)request.getSession().getAttribute("username"); Map onlineUserMap=(Map) sc.getAttribute("onlineUserMap");

String sessionId=request.getSession().getId();

String path= request.getContextPath();

//onlineUserMap==null 说明还没有用户登录过

//username==null 说明该用户超时或未登录

if(onlineUserMap!=null && username!=null ){

//获取sessionId String id=(String) onlineUserMap.get(username);

if(id!=null && id.trim().equals(sessionId)){

//取得sessionId与当前相等，说明此用户在使用状态 arg2.doFilter(request,response);

}else{

//说明已经被提出

response.setCharacterEncoding("gb2312");

response.setContentType("text/html");

PrintWriter out = response.getWriter();

out.println("");

out.flush();

out.close();

} }else{

//说明未登录

response.setCharacterEncoding("gb2312");

response.setContentType("text/html");

PrintWriter out = response.getWriter();

out.println("");

out.flush();

out.close();

}

}

logout.jsp

String username=(String)request.getSession().getAttribute("username");

Map onlineUserMap=(Map) application.getAttribute("onlineUserMap");

if(onlineUserMap!=null && username!=null){

onlineUserMap.remove(username);

}

session.invalidate();

%>

location.href="login.jsp";

posted on 2009-06-10 23:40 e寒-modify 阅读(235) 评论(0)  编辑  收藏