base64url in java

Question

https://web.archive.org/web/20110422225659/https://en.wikipedia.org/wiki/Base64#URL_applications

talks about base64Url - Decode

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a modified Base64 for U

Answer 1

@ufk's answer works, but you don't actually need to set the urlSafe flag when you're just decoding.

urlSafe is only applied to encode operations. Decoding seamlessly handles both modes.

Also, there are some static helpers to make it shorter and more explicit:

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.StringUtils;

public static String base64UrlDecode(String input) {
  StringUtils.newStringUtf8(Base64.decodeBase64(input));
}

Docs

• newStringUtf8()
• decodeBase64()