[Java知识库]HttpClient当中的判断当前是否可以使用缓存代码实现

public boolean isServableFromCache(final HttpRequest request){
   final String method = request.getRequestLine().getMethod();
   final protocolVersion pv = request.getRequestLine().getProtocolVersion();
   //如果请求不是HTTP1.1，不能走缓存
   if(HttpVersion.HTTP_1_1.compareToVersion(pv) != 0){
 return false;
}
 //如果请求方法不是GET或者HEAD方法，不能走缓存
 if(!(method.equals(HeaderConstants.GET_METHOD))||method.equals(HeaderConstants.HEAD_METHOD)){
  return false;
 }

 //如果请求头有Pragma，不能走缓存
 if(request.getHeaders(HeaderConstants.PRAGMA).length>0){
    return false;
  }

  //如果请求头Cache-Control为no-store不能走缓存
  final Header[] cacheControlHeaders = request.getHeaders(HeaderConstants.CACHE_CONTROL);
  for(final Header cacheControl:cacheControlHeaders){
     for(final HeaderELement cacheControlElement :  cacheControl.getElements()){
       if("no-store".equalsIgnoreCase(cacheControlElement.getName())){
      return false;
     }
     if("no-cache".equals(cacheControlElement.getName())){
       return false;
     }
     }
  }
    return true;
}