Encode And Decode Base64 Data In Javascript And Java

Posted By : S. Ajit | 09-Apr-2017

Base64 is a generic encoding schemes that encode binary data by treating it numerically and translating it into a base 64 representation.

Lets first talk about encoding and decoding javascript, In javascript to encode a string we use btoa function. It is a global function that encode a string to base64 string and to decode the encoded base64 string we use atob function. Here is a example:

/***** Encoding And Decoding Base64 In Javascript ******/

var text = "Highlight";

// Encode the String
var encodedString = btoa(text);
console.log(encodedString); // Outputs: "SGlnaGxpZ2h0"

// Decode the String 
var decodedString = cell (encodedString);
console.log(decodedString); // Outputs: "Highlight"

In java we use java.util's Base64 class to encode and decode base64 string. Here is a example:

/***** Encoding And Decoding Base64 In Java ******/

String str = "Highlight";

Encoder encoder = Base64.getEncoder();
String encodedString = encoder.encodeToString(str.getBytes());
System.out.println(encodedString); // Outputs: "SGlnaGxpZ2h0"

Decoder decoder = Base64.getDecoder();
byte[] decodedByte = decoder.decode(encodedString);
String decodedString = new String(decodedByte);
System.out.println(decodedString);  // Outputs: "Highlight"

We have used Base64 class of java.util class, it is available since JDK 1.8 . Base64 class has both encoder and decoder method.

Now lets take another example in java to save base64 image data.

/***** Decoding Base64 Image In Java ******/

String partSeparator = ",";
if (imageBase64.contains(partSeparator)) {
    String encodedImg = imageBase64.split(partSeparator)[1];
    byte[] decodedImg = Base64.getDecoder().decode(encodedImg.getBytes(StandardCharsets.UTF_8));
    InputStream in = new ByteArrayInputStream(decodedImg);
    String updatedFileName = UUID.randomUUID().toString() + ".png";
    BufferedImage ImageFromConvert = ImageIO.read( in );
    File profilePicUrl = new File(profileImageLocation + "/" + updatedFileName);
    ImageIO.write(ImageFromConvert, "png", profilePicUrl); in .close();
}