Base64 support option without Commons Codec dependency on Java 6/7 [SPR-12938]

[spring-projects-issues]

Phil Webb opened SPR-12938 and commented

Base64Utils currently requires Java 8 or Apache Commons Codec. It would be useful if we could include a direct implementation so that it always works.

We can crib code from
https://github.com/spring-projects/spring-security/blob/master/crypto/src/main/java/org/springframework/security/crypto/codec/Base64.java

---

Affects: 4.1 GA

Issue Links:

• Base64Utils: Support URL and filename safe alphabet (RFC 4648) [SPR-13784] #22188 Base64Utils: Support URL and filename safe alphabet (RFC 4648)

Referenced from: commits a5349eb

[spring-projects-issues]

Juergen Hoeller commented

We're currently only using Base64Utils in our GSON support... Are there any other places where it's being used already? Frankly, I'm not too fond of maintaining our own implementation if it's not needed on Java 8+ anyway.

Juergen

[spring-projects-issues]

Phil Webb commented

Probably not directly in Spring Framework. Spring Boot uses Base64 in TestRestTemplate and I recently also needed it again elsewhere in Boot. There is also a copy in Spring Data Redis, Spring Security. You're probably right that it's a problem that will solve itself once enough people are on Java 8.

[spring-projects-issues]

Thomas Darimont commented

There is a Base64 implementation in the JDK since the inclusion of JAXB in Java 6:

javax.xml.bind.DatatypeConverter class has 2 static methods – parseBase64Binary for byte[] to String and printBase64Binary for String to byte[], which are used for Base64 encoding and decoding.

See:
http://java-performance.info/base64-encoding-and-decoding-performance/

[spring-projects-issues]

Juergen Hoeller commented

Since javax.xml.bind.DatatypeConverter is only designed to convert between String values and byte array representations, we can only really use it as a fallback for our encodeToString and decodeFromString methods. We're doing that as of 4.2 RC2, just requiring Java 8 / Commons Codec for encode/decode calls between byte arrays.

Juergen

[spring-projects-issues]

Thomas Darimont commented

Just a slight note here, as I just found out that there is a minor difference between the encode output of sun.misc.Base64Encoder.encode and the DatatypeConverter.printBase64Binary / JDK 8's Base64.getEncoder().encode(..). The sun.misc.Base64Encoder.encode output is wrapped around 76 chars with newlines in between, where the JDK 8 Base64 and DatatypeConverter produce one long String as illustrated by the following example.

The sun.misc.Base64Encoder can parse either String so it shouldn't be a problem here - just beware that the output could look different.

package training.java8;

import javax.xml.bind.DatatypeConverter;
import java.util.Base64;

/**
 * Created by tom on 03.08.15.
 */
public class Base64Differences {

    public static void main(String[] args) throws Exception {

        String encoded = "V2hhdCBhIGNhcmVmdWwgcmVhZGVyIHlvdSBhcmUhICBUaGlzIHZhbHVlIGlzIGJhc2UtNjQtZW5jb2RlZCBiZWNhdXNlIGl0IGhhcyBhIGNvbnRyb2wgY2hhcmFjdGVyIGluIGl0IChhIENSKS4NICBCeSB0aGUgd2F5LCB5b3Ugc2hvdWxkIHJlYWxseSBnZXQgb3V0IG1vcmUu";

        System.out.println("JAXB DatatypeConverter: ");
        {
            String decoded = new String(DatatypeConverter.parseBase64Binary(encoded));
            String encodedAgain = DatatypeConverter.printBase64Binary(decoded.getBytes());

            System.out.println(encoded);
            System.out.println(decoded);
            System.out.println(encodedAgain);
        }
        System.out.println();
        System.out.println("JDK 8 Base 64: ");
        {

            String decoded = new String(Base64.getDecoder().decode(encoded));
            String encodedAgain = Base64.getEncoder().encodeToString(decoded.getBytes());

            System.out.println(encoded);
            System.out.println(decoded);
            System.out.println(encodedAgain);
        }
        System.out.println();
        System.out.println("sun.misc.BASE64Encoder/Decoder: ");
        {
            String decoded = new String(new sun.misc.BASE64Decoder().decodeBuffer(encoded));
            String encodedAgain = new sun.misc.BASE64Encoder().encode(decoded.getBytes());

            System.out.println(encoded);
            System.out.println(decoded);
            System.out.println(encodedAgain);
        }

    }
}

Output:

JAXB DatatypeConverter: 
V2hhdCBhIGNhcmVmdWwgcmVhZGVyIHlvdSBhcmUhICBUaGlzIHZhbHVlIGlzIGJhc2UtNjQtZW5jb2RlZCBiZWNhdXNlIGl0IGhhcyBhIGNvbnRyb2wgY2hhcmFjdGVyIGluIGl0IChhIENSKS4NICBCeSB0aGUgd2F5LCB5b3Ugc2hvdWxkIHJlYWxseSBnZXQgb3V0IG1vcmUu
  By the way, you should really get out more.
V2hhdCBhIGNhcmVmdWwgcmVhZGVyIHlvdSBhcmUhICBUaGlzIHZhbHVlIGlzIGJhc2UtNjQtZW5jb2RlZCBiZWNhdXNlIGl0IGhhcyBhIGNvbnRyb2wgY2hhcmFjdGVyIGluIGl0IChhIENSKS4NICBCeSB0aGUgd2F5LCB5b3Ugc2hvdWxkIHJlYWxseSBnZXQgb3V0IG1vcmUu

JDK 8 Base 64
V2hhdCBhIGNhcmVmdWwgcmVhZGVyIHlvdSBhcmUhICBUaGlzIHZhbHVlIGlzIGJhc2UtNjQtZW5jb2RlZCBiZWNhdXNlIGl0IGhhcyBhIGNvbnRyb2wgY2hhcmFjdGVyIGluIGl0IChhIENSKS4NICBCeSB0aGUgd2F5LCB5b3Ugc2hvdWxkIHJlYWxseSBnZXQgb3V0IG1vcmUu
  By the way, you should really get out more.
V2hhdCBhIGNhcmVmdWwgcmVhZGVyIHlvdSBhcmUhICBUaGlzIHZhbHVlIGlzIGJhc2UtNjQtZW5jb2RlZCBiZWNhdXNlIGl0IGhhcyBhIGNvbnRyb2wgY2hhcmFjdGVyIGluIGl0IChhIENSKS4NICBCeSB0aGUgd2F5LCB5b3Ugc2hvdWxkIHJlYWxseSBnZXQgb3V0IG1vcmUu

sun.misc.BASE64Encoder/Decoder
V2hhdCBhIGNhcmVmdWwgcmVhZGVyIHlvdSBhcmUhICBUaGlzIHZhbHVlIGlzIGJhc2UtNjQtZW5jb2RlZCBiZWNhdXNlIGl0IGhhcyBhIGNvbnRyb2wgY2hhcmFjdGVyIGluIGl0IChhIENSKS4NICBCeSB0aGUgd2F5LCB5b3Ugc2hvdWxkIHJlYWxseSBnZXQgb3V0IG1vcmUu
  By the way, you should really get out more.
V2hhdCBhIGNhcmVmdWwgcmVhZGVyIHlvdSBhcmUhICBUaGlzIHZhbHVlIGlzIGJhc2UtNjQtZW5j
b2RlZCBiZWNhdXNlIGl0IGhhcyBhIGNvbnRyb2wgY2hhcmFjdGVyIGluIGl0IChhIENSKS4NICBC
eSB0aGUgd2F5LCB5b3Ugc2hvdWxkIHJlYWxseSBnZXQgb3V0IG1vcmUu