使用java下载文件时如何获取原始文件名

How to get original file name when i download file from URL with java like this

当我用这样的URL从URL下载文件时如何获取原始文件名

File file = new File( "test" ) ;
FileUtils.copyURLToFile(URL, file)

Because when i create file i must put a name but at this stage i don't know yet the original name of downloading file.

因为当我创建文件时我必须输入一个名称但在此阶段我还不知道下载文件的原始名称。

1 个解决方案

#1

For me the suggested file name is stored in the header file Content-Disposition:

对我来说，建议的文件名存储在头文件Content-Disposition中：

Content-Disposition: attachment; filename="suggestion.zip"

I am downloading a file from nexus, so for different servers/applications it might be stored in a different header field but it is easy to find out with some tools like firebug for firefox.

我正在从nexus下载文件，因此对于不同的服务器/应用程序，它可能存储在不同的头字段中，但很容易找到一些工具，如firebug for firefox。

The following lines work fine for me

以下几行对我来说很好

URL url = new URL(urlString);
// open the connection
URLConnection con = url.openConnection();
// get and verify the header field
String fieldValue = con.getHeaderField("Content-Disposition");
if (fieldValue == null || ! fieldValue.contains("filename=\"")) {
  // no file name there -> throw exception ...
}
// parse the file name from the header field
String filename = fieldValue.substring(fieldValue.indexOf("filename=\"") + 10, fieldValue.length() - 1);
// create file in systems temporary directory
File download = new File(System.getProperty("java.io.tmpdir"), filename);

// open the stream and download
ReadableByteChannel rbc = Channels.newChannel(con.getInputStream());
FileOutputStream fos = new FileOutputStream(download);
try {
  fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
} finally {
  fos.close();
}

#1