ios webview 拦截404

直接上代码

- (void)webViewDidFinishLoad:(UIWebView *)webView {
 
    // 404拦截处理，当后台配有404页面时，可能会出现404展示到一半，然后直接隐藏后，显示空白处理的效果，产品接受此处理
    NSCachedURLResponse *resp = [[NSURLCache sharedURLCache] cachedResponseForRequest:webView.request];
    
    
    if ([resp.response isKindOfClass:[NSHTTPURLResponse class]]) {
        NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse*)resp.response;
        NSInteger statusCode = [httpResponse statusCode];
        if (statusCode == 404) {
            
            [self hideNetworkErrorTipView];
            
            self.title = @"";
            self.webView.hidden = YES;
            [self.view showNoDataTipViewWithText:@"找不到指定的页面" imageString:@"search"];
            
            return;
        }
    }
  
    
}

揣测：
当webview加载的时候，会暂时缓存请求（如果没有特别指定千万别缓存的情况下），所以通过[NSURLCache sharedURLCache]的方式能够拿到缓存的response，至于为什么能够强制转换NSURLResponse为NSHTTPURLResponse，是因为我们走的http请求，最终实例是一个NSHTTPURLResponse。

NSHTTPURLResponse的类说明
An NSHTTPURLResponse object represents a response to an
HTTP URL load. It is a specialization of NSURLResponse which
provides conveniences for accessing information specific to HTTP
protocol responses.