java查找url是否引用现有对象

Question

我有很多URL可以在客户端上显示。但我必须选择指向现有对象的URL（在我的情况下是图像）。有人知道如果我的url引用的是未从存储中删除的图像，我该如何获取

Answer 1

像这样的怎么样

URL url = new URL("http://upload.wikimedia.org/wikipedia/commons/8/84/Example.svg");
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
int statusCode = connection.getResponseCode();//OK if returned value is 200

Answer 2

您可以尝试打开一条流：

public static boolean exists(URL url) throws IOException {
    try {
        InputStream inputStream = url.openStream();
        return inputStream != null;
    }catch (FileNotFoundException e){
        return false;
    }
}

public static void main(String[] args) throws Exception {
    System.out.println(exists(new URL("https://www.google.de/images/srpr/logo11w.png")));
    System.out.println(exists(new URL("https://www.google.de/images/srpr/foo.png")));
}