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"

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标头字段中，但是很容易通过诸如firebug的firebug之类的工具来查找。

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();
}