public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {

System.out.println("IllegalVisitorFilter doFilter() is launched.");

HttpServletRequest request=(HttpServletRequest) req;

HttpServletResponse response=(HttpServletResponse) resp;

String url=request.getRequestURI();

String methodName=request.getParameter("method");

?url=url+"_"+methodName;

System.out.println(url); // request路徑中是否包含login字符串？目的是判斷是否需要攔截？ if(url.contains("login"))

{ chain.doFilter(request, response); return; }

?System.out.println("**********************");

Object object = request.getSession().getAttribute("username");

if(object==null){

System.out.println("當(dāng)前沒有登錄哦，退回登錄界面！");

response.sendRedirect(request.getContextPath()+"/login.jsp"); }

?else{

System.out.println(object.toString());

?chain.doFilter(request, response); }

?}