public class TestFillter implements Filter{ @Override public void destroy() { } @Override public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException { HttpServletRequest request=(HttpServletRequest) arg0; HttpServletResponse response=(HttpServletResponse) arg1; String name=request.getHeader("PARA_TOKEN"); if(name!=null)                   { arg2.doFilter(request, response);                         return;                    } //否则返回主界面 response.sendRedirect(request.getContextPath()+"/"); } @Override public void init(FilterConfig arg0) throws ServletException { } }