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?
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.
The method encodeBase64(byte[]) is undefined for the type Base64
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); 
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.
java.util.Base64 is available starting Java 8, not 11.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")); } 
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.
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); } } 
DataTypeConverterworks just fine, the original poster has just mixed the order. It should look like this:String str = DatatypeConverter.printBase64Binary("user:123".getBytes());String res = new String(DatatypeConverter.parseBase64Binary(str));