CODEWITHSUNDEEP
javabase64decodeencode
Sameera Kumarasingha
Sameera Kumarasingha

Reputation: 2988

Base64 Java encode and decode a string

I want to encode a string into base64 and transfer it through a socket and decode it back.

But after decoding it gives different answer.

Following is my code and result is "77+9x6s="

import javax.xml.bind.DatatypeConverter;

    public class f{

       public static void main(String a[]){

          String str = new String(DatatypeConverter.parseBase64Binary("user:123"));
          String res = DatatypeConverter.printBase64Binary(str.getBytes());
          System.out.println(res);
       }
    }

Any idea about how to implement this?

Upvotes: 189

Views: 765441

Answers (6)

nocdib
nocdib

Reputation: 1446

The accepted answer uses the Apache Commons package but this is how I did it using Java's native libraries

Java 8 and up

import java.util.Base64;

public class Base64Encoding {

    public static void main(String[] args) {
        Base64.Encoder enc = Base64.getEncoder();
        Base64.Decoder dec = Base64.getDecoder();
        String str = "77+9x6s=";

        // encode data using BASE64
        String encoded = enc.encodeToString(str.getBytes());
        System.out.println("encoded value is \t" + encoded);

        // Decode data
        String decoded = new String(dec.decode(encoded));
        System.out.println("decoded value is \t" + decoded);
        System.out.println("original value is \t" + str);
    }
}

Java 6 - 10

import java.io.UnsupportedEncodingException;    
import javax.xml.bind.DatatypeConverter;

public class EncodeString64 {
    public static void main(String[] args) throws UnsupportedEncodingException {

        String str = "77+9x6s=";
        // encode data using BASE64
        String encoded = DatatypeConverter.printBase64Binary(str.getBytes());
        System.out.println("encoded value is \t" + encoded);

        // Decode data 
        String decoded = new String(DatatypeConverter.parseBase64Binary(encoded));
        System.out.println("decoded value is \t" + decoded);
        
        System.out.println("original value is \t" + str);
    }
}

The better way would be to try/catch the encoding/decoding steps but hopefully you get the idea.

Upvotes: 67

Dark Knight
Dark Knight

Reputation: 8357

You can use following approach:

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

// Encode data on your side using BASE64
byte[] bytesEncoded = Base64.encodeBase64(str.getBytes());
System.out.println("encoded value is " + new String(bytesEncoded));

// Decode data on other side, by processing encoded data
byte[] valueDecoded = Base64.decodeBase64(bytesEncoded);
System.out.println("Decoded value is " + new String(valueDecoded));

Hope this answers your doubt.

Upvotes: 275

Yehonatan
Yehonatan

Reputation: 3225

The following is a good solution - 

import android.util.Base64;

String converted = Base64.encodeToString(toConvert.toString().getBytes(), Base64.DEFAULT);

String stringFromBase = new String(Base64.decode(converted, Base64.DEFAULT));

That's it. A single line encoding and decoding.

Upvotes: 24

Lakshma Gopidi
Lakshma Gopidi

Reputation: 1651

Java 8 now supports BASE64 Encoding and Decoding. You can use the following classes: java.util.Base64, java.util.Base64.Encoder and java.util.Base64.Decoder.

Example usage:

// encode with padding
String encoded = Base64.getEncoder().encodeToString(someByteArray);

// encode without padding
String encoded = Base64.getEncoder().withoutPadding().encodeToString(someByteArray);

// decode a String
byte [] barr = Base64.getDecoder().decode(encoded);

Upvotes: 165

Tahong Shen
Tahong Shen

Reputation: 101

import javax.xml.bind.DatatypeConverter;

public class f{

   public static void main(String a[]){

      String str = new String(DatatypeConverter.printBase64Binary(new String("user:123").getBytes()));
      String res = DatatypeConverter.parseBase64Binary(str);
      System.out.println(res);
   }
}

Upvotes: 8

iamiddy
iamiddy

Reputation: 3073

For Spring Users , Spring Security has a Base64 class in the org.springframework.security.crypto.codec package that can also be used for encoding and decoding of Base64. Ex.

 public static String base64Encode(String token) {
    byte[] encodedBytes = Base64.encode(token.getBytes());
    return new String(encodedBytes, Charset.forName("UTF-8"));
}


public static String base64Decode(String token) {
    byte[] decodedBytes = Base64.decode(token.getBytes());
    return new String(decodedBytes, Charset.forName("UTF-8"));
}

Upvotes: 27

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