How to convert String to byte[] in Java?

By mkyong | Updated: January 17, 2022

Viewed: 12,257 (+53 pv/w)

Tags: byte array java java string string utf-8

In Java, we can use str.getBytes(StandardCharsets.UTF_8) to convert a String into a byte[].

  String str = "This is a String";

  //  default charset, a bit dangerous
  byte[] output1 = str.getBytes();

  // in old days, before java 1.7
  byte[] output2 = str.getBytes(Charset.forName("UTF-8"));

  // the best , java 1.7+ , new class StandardCharsets
  byte[] output3 = str.getBytes(StandardCharsets.UTF_8);

Table of contents

• 1. Convert String to byte[]
• 2. Convert byte[] to String
• 3. Download Source Code
• 4. References

1. Convert String to byte[]

Below is a complete example of converting a String to a byte[] type, and Base64 encodes it.

package com.mkyong.string;

import java.nio.charset.StandardCharsets;
import java.util.Base64;

public class ConvertStringToBytes {

    public static void main(String[] args) {

        String example = "This is an example";

        // the best , java 1.7+
        byte[] output = example.getBytes(StandardCharsets.UTF_8);

        System.out.println("Text : " + example);

        String base64encoded = Base64.getEncoder().encodeToString(output);

        System.out.println("Text [Base64] : " + base64encoded);

    }

}

Output

Text : This is an example
Text [Base64] : VGhpcyBpcyBhbiBleGFtcGxl

2. Convert byte[] to String

In Java, we can use new String(bytes, StandardCharsets.UTF_8) to convert byte[] to a String.

package com.mkyong.string;

import java.nio.charset.StandardCharsets;

public class ConvertBytesToString {

  public static void main(String[] args) {

      // String to byte[]
      byte[] bytes = "mkyong".getBytes(StandardCharsets.UTF_8);

      // byte[] to String
      String s = new String(bytes, StandardCharsets.UTF_8);

      // mkyong
      System.out.println(s);

  }

}

Output

mkyong

3. Download Source Code

4. References

• How to create Zip file in Java
• How to convert byte arrays to String in Java
• Java 11 – String JavaDoc
• Wikipedia – UTF-8