如何在旧的PHP系统中使用PHP 5.3之后的库

require __DIR__ . '/vendor/autoload.php';
require __DIR__ . '/inc/zentao/nb/Autoloader.php';
\zentao\nb\Autoloader::register();

$app = \zentao\core\Application::app(dirname(ZTNB_ROOT)); //禅道的router

$slim = new \Slim\Slim();

$routes = require __DIR__ . '/data/config/routes.php';

foreach ($routes as $method => $_routes) {
 if ($_routes) {
  foreach ($_routes as $rule => $map) {
   $slim->$method($rule, '\\zentao\\nb\\resource\\' . $map);
  }
 }
}

$slim->run();

<?php

namespace zentao\nb;

/**
 * 资源类 父类
 */
class Resource {

 public function __construct() {
  
 }

 /**
  * Load the model file of one module.
  * 
  * @param string  $methodName The method name, if empty, use current module's name.
  * @access public
  * @return object|bool If no model file, return false. Else return the model object.
  */
 protected function loadModel($moduleName) {
  $modelFile = \helper::setModelFile($moduleName);

  /* If no model file, try load config. */
  if (!\helper::import($modelFile)) {
   $this->app->loadConfig($moduleName, false);
   $this->app->loadLang($moduleName);
   $this->dao = new dao();
   return false;
  }

  $modelClass = class_exists('ext' . $moduleName . 'model') ? 'ext' . $moduleName . 'model' : $moduleName . 'model';
  $modelClass = '\\' . $modelClass;
  if (!class_exists($modelClass))
   $this->app->triggerError(" The model $modelClass not found", __FILE__, __LINE__, $exit = true);

  $this->$moduleName = new $modelClass();
  $this->dao = $this->$moduleName->dao;
  return $this->$moduleName;
 } 

<?php

namespace zentao\nb\resource;

use zentao\nb\enum\BugType;

/**
 * 项目自行定义的问题分类
 */
class IssueCategory extends \zentao\nb\resource {
 
 public function fetchAll($format = 'json') {
  global $app;

  $types = $app->loadLang('bug')->bug->typeList;
  $issue_categories = array();
  foreach ($types as $key => $name) {
   
   $issue_categories[] = array('id' => BugType::getIdByInterId($key), 'name' => $name);
  }
  
  echo json_encode(array('issue_categories' => $issue_categories));
 }
 
 /**
  * 根据项目来取其中定义的分类
  * @param int $projectId
  * @param string $format
  */
 public function fetchAllByProjectId($projectId, $format = 'json') {
  $model = $this->loadModel('project');
  $project = $model->getById($projectId);//TODO 支持按项目代号查找
  if (!$project) {
   $this->responseNotExixted();
  }
  
  global $app;
  $types = $app->loadLang('bug')->bug->typeList;
  $issue_categories = array();
  foreach ($types as $key => $name) {
   
   $issue_categories[] = array('id' => BugType::getIdByInterId($key), 'project' => array('id' => $projectId, 'name' => $project->name), 'name' => $name);
  }
  
  echo json_encode(array(
   'issue_categories' => $issue_categories,
   'total_count' => 2
  ));
 }
}