ContentMD5Writer.java 文件源码

@Override
public void aroundWriteTo(WriterInterceptorContext context) throws IOException, WebApplicationException
{
   MessageDigest digest = null;
   try
   {
      digest = MessageDigest.getInstance("MD5");
   }
   catch (NoSuchAlgorithmException e)
   {
      throw new IllegalArgumentException(e);
   }
   ByteArrayOutputStream buffer = new ByteArrayOutputStream();
   DigestOutputStream digestStream = new DigestOutputStream(buffer, digest);
   OutputStream old = context.getOutputStream();
   context.setOutputStream(digestStream);

   try
   {
      context.proceed();

      byte[] hash = digest.digest();
      String encodedHash = Base64.encodeBytes(hash);
      context.getHeaders().putSingle("Content-MD5", encodedHash);

      byte[] content = buffer.toByteArray();
      old.write(content);
   }
   finally
   {
      context.setOutputStream(old);
   }
}