/**
 * 显示404错误页面
 *
 * @param 
 * @author 编程之家 jb51.cc jb51.cc
 **/
function show_404_page() {
 if (is_file(TEMPLATE_PATH . '404.PHP')) {
  header("HTTP/1.1 404 Not Found");
  include View::getView('404');
  exit;
 } else {
  emMsg('404',BLOG_URL);
 }
}