如何在java中从URL计算文件大小 [英] How to calculate a file size from URL in java

问题描述

我正在尝试从网络服务获取一堆pdf链接，我想向用户提供每个链接的文件大小。

I'm attempting to get a bunch of pdf links from a web service and I want to give the user the file size of each link.

是否有完成这项任务的方法是什么？

Is there a way to accomplish this task?

谢谢

推荐答案

使用HEAD请求，你可以这样做：

Using a HEAD request, you can do something like this:

private static int getFileSize(URL url) {
    URLConnection conn = null;
    try {
        conn = url.openConnection();
        if(conn instanceof HttpURLConnection) {
            ((HttpURLConnection)conn).setRequestMethod("HEAD");
        }
        conn.getInputStream();
        return conn.getContentLength();
    } catch (IOException e) {
        throw new RuntimeException(e);
    } finally {
        if(conn instanceof HttpURLConnection) {
            ((HttpURLConnection)conn).disconnect();
        }
    }
}

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