base64.decode java

Basics of Base64 Encoding and Decoding

Base64 encoding and decoding in Java convert binary data into text format, ensuring safe data transmission via text-based mediums. The java.util.Base64 class, available since Java 8, provides static methods for encoding and decoding.

The standard Base64 encoding uses an alphabet of a-z, A-Z, 0-9, /, and +. Here's an example of encoding and decoding a message:


String message = "Tech is awesome!";
String encodedMessage = Base64.getEncoder().encodeToString(message.getBytes(StandardCharsets.UTF_8));
System.out.println(encodedMessage);

byte[] decodedBytes = Base64.getDecoder().decode(encodedMessage);
String decodedMessage = new String(decodedBytes, StandardCharsets.UTF_8);
System.out.println(decodedMessage);


For URL and filename safety, the getUrlEncoder() method replaces + and / with – and _.

MIME encoding is available for mail purposes, ensuring each output line stays within 76 characters.

Decoding reverses the process, turning Base64 text back into readable format. Decoders are available for Basic, URL safe, and MIME types using getDecoder(), getUrlDecoder(), and getMimeDecoder() methods respectively.

Apache Commons Codec offers an alternative for encoding and decoding strings:


Base64 base64 = new Base64();
String data = "Java programming language.";
String encodedStr = new String(base64.encode(data.getBytes()), StandardCharsets.UTF_8);
System.out.println(encodedStr);


Base64 in Java focuses on transferring data safely as text, maintaining data integrity during transport and storage, despite increasing data size.

Implementing Basic Base64 Encoding and Decoding

Let's explore some practical examples of Base64 encoding and decoding in Java.

To encode a simple string:


String simpleMessage = "Java is versatile.";
String base64Encoded = Base64.getEncoder().encodeToString(simpleMessage.getBytes(StandardCharsets.UTF_8));
System.out.println("Encoded: " + base64Encoded);


To decode back to the original message:


byte[] decodedBytes = Base64.getDecoder().decode(base64Encoded);
String decodedMessage = new String(decodedBytes, StandardCharsets.UTF_8);
System.out.println("Decoded: " + decodedMessage);


Base64 can also be used with file contents:


File file = new File("path/to/your/file.txt");
String encodedFileContent = Base64.getEncoder().encodeToString(Files.readAllBytes(file.toPath()));
System.out.println("Encoded File Content: " + encodedFileContent);


This utility is particularly useful for maintaining file integrity in text-based environments, such as sharing images through XML or conveying scripting data via JSON.

Advanced Encoding Variants in Base64

Advanced encoding variants in Base64 for Java offer solutions for various needs:

1. URL and Filename Safe variant (getUrlEncoder()): Replaces "+" and "/" with "-" and "_", ideal for web addresses or file paths.
2. MIME encoding (getMimeEncoder()): Designed for email protocols, it formats output by breaking lines into 76-character lengths, adhering to email standards.

These variants ensure data integrity and usability across various platforms and mediums, whether preparing data for text-based schemas or sending information via email.

Familiarity with these variants helps in selecting the most appropriate option for specific project requirements, ensuring data can be transformed and decoded effectively across different platforms.

Writio: Your AI content writer partner. This article was authored by Writio.

1. Oracle. java.util.Base64 (Java Platform SE 8). Oracle Java Documentation.
2. HowToDoInJava. Java 8 Base64 Encoding and Decoding.
3. GeeksforGeeks. How to Convert a String to Base64 Encoded String in Java?