有没有办法从Java中的文件扩展名生成Content-Type标头？

Question

I have a Java application which sometimes has to generate a Content-Type header from a filename alone. Is there a way to estimate the Content-Type for common extensions? (eg ".pdf" maps to "application/pdf", etc)

Answer 1

Yes, via the JavaBeans Activation Framework (javax.activation).

import java.io.File;
import javax.activation.MimetypesFileTypeMap;
...
return new MimetypesFileTypeMap().getContentType(new File("brognitz.jpg"));

You can also add your own content types if the Java built-in database is inadequate.

Edit: Jason Day's answer is just as correct, as far as I can tell.

Answer 2

是的， URLConnection.guessContentTypeFromName就是这样做的。

Answer 3

你加载了常见类型的哈希表？