对于不存在的URL，Java HTTP getResponseCode返回200 [英] Java HTTP getResponseCode returns 200 for non-existent URL

问题描述

我原本期望此代码返回404，但它会产生输出：

I was expecting this code to return a 404, however it produces the output :

响应代码为200

是否有可能学习如何区分现有和不存在的网页。 。 。非常感谢，

Would it be possible to learn how to differentiate between existent and non-existent web pages . . . thanks so much,

    try
    {
    // create the HttpURLConnection
    URL url = new URL("http://www.thisurldoesnotexist");
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();

    System.out.println("Response code is " + connection.getResponseCode());
    }

推荐答案

编辑：我看到你了我打电话给 openConnection（）但不是 connect（） - 这可能是问题吗？我会期待 getResponseCode（）实际发出请求（如果还没有），但值得尝试...

I see you've call openConnection() but not connect() - could that be the problem? I would expect getResponseCode() to actually make the request if it hasn't already, but it's worth just trying that...

这表明你可能有一些DNS解析器重定向到帮助者（垃圾邮件）页面，或类似的东西。

That suggests you've possible got some DNS resolver which redirects to a "helper" (spam) page, or something like that.

查看确切内容的最简单方法是使用 Wireshark - 拥有并捕获流量（仅限HTTP，使生活更轻松），然后运行您的代码。您应该能够看到正在发生的事情。

The easiest way to see exactly what's going on here is to use Wireshark - have that up and capturing traffic (HTTP-only, to make life easier) and then run your code. You should be able to see what's going on that way.

请注意，我不会期望404 - 因为这将涉及能够找到一个Web服务器谈谈开始。如果您尝试转到不涉及的主机，则不应该存在HTTP响应 。我希望 connect（）抛出异常。

Note that I wouldn't have expected a 404 - because that would involve being able to find a web server to talk to to start with. If you're trying to go to a host which doesn't involve, there shouldn't be an HTTP response at all. I'd expect connect() to throw an exception.

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