使用DigestInputStream计算来自同一InputStream的多个校验和

Question

我试图弄清楚如何基于相同的InputStream使用读取多个摘要(md5,sha1,gpg)DigestInputStream.根据我在文档中检查的内容,似乎可以通过克隆摘要来实现.有人可以说明一下吗？

我不想重新读取流来计算校验和.

Answer 1

你可以换一个DigestInputStream绕DigestInputStream等递归:

DigestInputStream shaStream = new DigestInputStream(
    inStream, MessageDigest.getInstance("SHA-1"));
DigestInputStream md5Stream = new DigestInputStream(
    shaStream, MessageDigest.getInstance("MD5"));
// VERY IMPORTANT: read from final stream since it's FilterInputStream
byte[] shaDigest = shaStream.getMessageDigest().digest();
byte[] md5Digest = md5Stream.getMessageDigest().digest();