Java - Base64 Encoding and Decoding

---

---

The Base64 utility class was introduced in Java 8 that has inbuilt encoder and decoder for Base64 encoding and decoding. We've three types of Base64 encoding and decoding available. Following is a brief of these types added:

• Basic − Output is mapped to a set of characters lying in A-Za-z0-9+/. The encoder does not add any line feed in output, and the decoder rejects any character other than A-Za-z0-9+/.

• URL − Output is mapped to set of characters lying in A-Za-z0-9+_. Output is URL and filename safe.

• MIME − Output is mapped to MIME friendly format. Output is represented in lines of no more than 76 characters each, and uses a carriage return '\r' followed by a linefeed '\n' as the line separator. No line separator is present to the end of the encoded output.

Basic Base64 Encoding and Decoding

Basic Base64 encoder encodes the provided string without adding any line feed. This encoder uses characters lying in A-Za-z0-9+/ character set. Following is the snippet explaining the use of Base64 encoder.

String stringToEncode = "TutorialsPoint?java8";
// Encode using basic encoder
String base64encodedString = Base64.getEncoder().encodeToString(stringToEncode.getBytes("utf-8"));

Simple Base64 decoder decodes the Base64 encoded string by rejecting any character other than A-Za-z0-9+/. Following is the snippet explaining the use of Base64 decoder.

// Decode the base64 encoded string using basic decoder
byte[] base64decodedBytes = Base64.getDecoder().decode(base64encodedString);
// print the decoded string		
System.out.println("Original String: " + new String(base64decodedBytes, "utf-8"));

Example: Basic Base64 Encoding and Decoding in Java

Following example showcases the use of Base64 basic encoder and decoder. We've first encoded a simple string using a encoder retrieved using Base64.getEncoder() and then returned encoded string is decoded using decoder retrieved using Base64.getDecoder() method.

package com.tutorialspoint;

import java.io.UnsupportedEncodingException;
import java.util.Base64;

public class Base64Tester {
   public static void main(String[] args) throws UnsupportedEncodingException {
      String stringToEncode = "TutorialsPoint?java";
      // Encode using basic encoder
      String base64encodedString = Base64.getEncoder().encodeToString(stringToEncode.getBytes("utf-8"));
      System.out.println("Encoded String: " + base64encodedString);

      // Decode the base64 encoded string using basic decoder
      byte[] base64decodedBytes = Base64.getDecoder().decode(base64encodedString);
      // print the decoded string		
      System.out.println("Decoded String: " + new String(base64decodedBytes, "utf-8"));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Encoded String: VHV0b3JpYWxzUG9pbnQ/amF2YQ==
Decoded String: TutorialsPoint?java

Base64 Encoding and Decoding for URL

URL Base64 encoder encodes the provided URL and makes it URL and filename safe. This encoder uses characters lying in A-Za-z0-9+/ character set. It encodes using the URL and Filename safe type base64 encoding scheme. Following is the snippet explaining the use of URL Base64 encoder.

String stringToEncode = "TutorialsPoint?java8";
// Encode using url encoder
String base64encodedString = Base64.getUrlEncoder().encodeToString(stringToEncode.getBytes("utf-8"));

URL Base64 decoder decodes the Base64 encoded string by rejecting any character other than A-Za-z0-9+/. It decodes using the URL and Filename safe type base64 encoding scheme. Following is the snippet explaining the use of Base64 decoder.

// Decode the base64 encoded string using basic decoder
byte[] base64decodedBytes = Base64.getUrlDecoder().decode(base64encodedString);
// print the decoded string		
System.out.println("Original String: " + new String(base64decodedBytes, "utf-8"));

Example: Base64 Encoding and Decoding for URL in Java

Following example showcases the use of Base64 URL encoder and decoder. We've first encoded a simple string using a encoder retrieved using Base64.getUrlEncoder() and then returned encoded string is decoded using decoder retrieved using Base64.getUrlDecoder() method.

package com.tutorialspoint;

import java.io.UnsupportedEncodingException;
import java.util.Base64;

public class Base64Tester {
   public static void main(String[] args) throws UnsupportedEncodingException {
      String stringToEncode = "TutorialsPoint?java";
      // Encode using url encoder
      String base64encodedString = Base64.getUrlEncoder().encodeToString(stringToEncode.getBytes("utf-8"));
      System.out.println("Encoded String: " + base64encodedString);

      // Decode the base64 encoded string using url decoder
      byte[] base64decodedBytes = Base64.getUrlDecoder().decode(base64encodedString);
      // print the decoded string		
      System.out.println("Decoded String: " + new String(base64decodedBytes, "utf-8"));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Encoded String: VHV0b3JpYWxzUG9pbnQ_amF2YQ==
Decoded String: TutorialsPoint?java

Base64 Encoding and Decoding for MIME Type Content

MIME Base64 encoder encodes the provided string content to MIME friendly format. Output is represented in lines of no more than 76 characters each, and uses a carriage return '\r' followed by a linefeed '\n' as the line separator. No line separator is present to the end of the encoded output. Following is the snippet explaining the use of MIME Base64 encoder.

String stringToEncode = "TutorialsPoint?java8";
// Encode using mime encoder
String base64encodedString = Base64.getMimeEncoder().encodeToString(stringToEncode.getBytes("utf-8"));

MIME Base64 decoder decodes the Base64 encoded string by rejecting any character other than A-Za-z0-9+/. It decodes using the MIME type base64 decoding scheme. Following is the snippet explaining the use of Base64 decoder.

// Decode the base64 encoded string using basic decoder
byte[] base64decodedBytes = Base64.getMIMEDecoder().decode(base64encodedString);
// print the decoded string		
System.out.println("Original String: " + new String(base64decodedBytes, "utf-8"));

Example: MIME Base64 Encoding and Decoding in Java

Following example showcases the use of Base64 MIME encoder and decoder. We've first encoded a simple string using a encoder retrieved using Base64.getMIMEEncoder() and then returned encoded string is decoded using decoder retrieved using Base64.getMIMEDecoder() method.

package com.tutorialspoint;

import java.io.UnsupportedEncodingException;
import java.util.Base64;
import java.util.UUID;

public class Base64Tester {
   public static void main(String[] args) throws UnsupportedEncodingException {
      StringBuilder stringBuilder = new StringBuilder();

      for (int i = 0; i < 10; ++i) {
         stringBuilder.append(UUID.randomUUID().toString());
         stringBuilder.append(",");
      }

      byte[] mimeBytes = stringBuilder.toString().getBytes("utf-8");
      String mimeEncodedString = Base64.getMimeEncoder().encodeToString(mimeBytes);
      System.out.println("Base64 Encoded String (MIME) : " + mimeEncodedString);

      // Decode the base64 encoded string using url decoder
      byte[] base64decodedBytes = Base64.getMimeDecoder().decode(mimeEncodedString);
      // print the decoded string		
      System.out.println("Decoded String: " + new String(base64decodedBytes, "utf-8"));
   }
}

Output

Let us compile and run the above program, this will produce the following result −

Base64 Encoded String (MIME) : NzRmNjkyODktYzJjZS00ZmU2LWEzYTUtMmFlMWRlMDQ1ZjU4LGQyNGQzMTU5LTVmOGUtNDZhMS04
NGRkLTBiMzNlNzc4ZjNiOCw2MmM1OTEzOS1kNmQwLTQ5MmQtYmUyMi01NmEzMTk5NmRkMTAsZDZh
NjBlNzctZjRjZi00Y2Q4LTk5MWEtYTY2ZDEzMzU4YjFjLGFlNDhkZmZjLTEwZjctNDk5OS05NTFj
LTU5ZGY1MjcyYjczNywxY2JiZjU0Ni0zNjc1LTQ4NzAtYTYxNC01MzkyODFkNjRjYmMsMTlhNTNi
ODEtODQ0OS00M2MyLTg4NmMtNDhmZThmZDZmN2E1LDQyNmRhZDE0LTEyNjItNGJhZC1hMWJlLTNm
ODc4MWE1YzhiMiw2NjEwMTgzZS03MGNkLTQzZTctOTRkNC0wZDgzZmY1MzhkNWYsOWMxNmMwM2Ut
ZWZmZS00Zjg2LWFkYzgtNjc3MThjYTVlYjI2LA==
Decoded String: 74f69289-c2ce-4fe6-a3a5-2ae1de045f58,d24d3159-5f8e-46a1-84dd-0b33e778f3b8,62c59139-d6d0-492d-be22-56a31996dd10,d6a60e77-f4cf-4cd8-991a-a66d13358b1c,ae48dffc-10f7-4999-951c-59df5272b737,1cbbf546-3675-4870-a614-539281d64cbc,19a53b81-8449-43c2-886c-48fe8fd6f7a5,426dad14-1262-4bad-a1be-3f8781a5c8b2,6610183e-70cd-43e7-94d4-0d83ff538d5f,9c16c03e-effe-4f86-adc8-67718ca5eb26,

Nested Classes of Base64 Class

Following classes are provided by Base64 class.

Base64 Class Methods

Following are the methods which provided by Base64 class to assist Base64 encoding/decoding.

Methods Inherited

This class inherits methods from the following class −

• java.lang.Object