Convert string to byte array using getBytes(encoding) method in Java

In the Java programming world, you can convert a string into a byte array by using the "getBytes()" function. The end result of this process is to obtain a byte array representation of the starting string, with the encoding specified by the method's specification. There are two different ways to convert a string to a byte array in Java by using the "getBytes()" function. The first strategy involves using the JVM's default character set encoding, which is an encoding technique. The second approach depends on the specific character set encoding provided and determines which encoding to use based on the requirements of the application in question.

In this article, we will take a closer look at both methods, while also providing code implementation and output examples for each method.

usage instructions

This article discusses three different ways to convert string to byte array in Java.

• Method 1 - The first method involves using the default character set encoding. Calling the 'getBytes()' method on a string object with no encoding specified causes the default character set encoding to be used. This method is suitable when the conversion does not require a specific encoding.

• Method 2 - The second method involves using a specific character set encoding for the "getBytes()" method. This method is useful when the conversion requires a different encoding than the default encoding. The choice of encoding depends on the specific requirements of the application.

• Method 3 - The third method uses the `ByteBuffer` class in Java. This class provides methods to convert a string to a byte array and vice versa. The `Charset` class is used to specify the encoding used for conversion. This approach can be helpful when dealing with complex character encodings or when more customizable conversions are required.

The getBytes(encoding) method takes a string parameter encoding, which specifies the character encoding scheme to be used. This method returns a byte array representing the string in the specified encoding. The syntax of this method is as follows -

grammar

byte[] byteArray = str.getBytes(encoding);

Where str is the string to be converted and encoding is the name of the encoding scheme.

algorithm

To convert string to byte array in Java you can follow these steps -

• Step 1 - Get the string to convert to a byte array.

• Step 2 - Decide which encoding to use for conversion. If no encoding is specified, the default character set encoding will be used.

• Step 3 - Call the "getBytes()" method on the string object and pass the encoding as parameter. This returns the byte array representation of the string.

• Step 4 - Save the byte array in a variable for future use.

• Step 5 - If the JVM does not support the specified encoding, the "getBytes()" method will throw "UnsupportedEncodingException". You can use a try-catch block to handle this exception.

• Step 6 - Print the byte array in a readable format using the `Arrays.toString()` method.

• Step 7 - If necessary, use the "new String(byteArray,encoding)" method to convert the byte array back to a string.

• Step 8 - The converted byte array is now available for further transmission or processing.

Note that additional steps or modifications may be required depending on the specific requirements of your application.

method 1

This method of converting a string to a byte array in Java uses the default character set encoding, which is the encoding used by the JVM by default. This approach is simple and straightforward, but may not be suitable if the application requires specific encoding.

Example

import java.util.Arrays;

public class StringToByteArray {
   public static void main(String[] args) {
      String str = "Hello, world!";
      byte[] byteArray = str.getBytes();
      System.out.println("Byte array using default charset encoding: " + Arrays.toString(byteArray));
   }
}

Output

Byte array using default charset encoding: [72, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100, 33]

Method 2

This method of converting a string to a byte array in Java allows us to specify a specific character set encoding to be used. This gives us greater control over the encoding used for conversion and ensures that the byte array is compatible with the target system.

Below is the same program code.

Example

import java.util.Arrays;
import java.io.UnsupportedEncodingException;

public class StringToByteArray {
   public static void main(String[] args) {
      String str = "Hello, world!";
      String encoding = "UTF-16";
      byte[] byteArray = null;
      try {
          byteArray = str.getBytes(encoding);
      } catch (UnsupportedEncodingException e) {
         e.printStackTrace();
      }
      System.out.println("Byte array using " + encoding + " encoding: " + Arrays.toString(byteArray));
   }
}

Output

Byte array using UTF-16 encoding: [-2, -1, 0, 72, 0, 101, 0, 108, 0, 108, 0, 111, 0, 44, 0, 32, 0, 119, 0, 111, 0, 114, 0, 108, 0, 100, 0, 33, 0]

In this output, we can see that the byte array contains two extra bytes (-2 and -1) at the beginning compared to the default encoding method. These two bytes represent the byte order of UTF-16 encoding.

Method 3

This method of converting string to byte array in Java uses ByteBuffer class which provides methods to convert string to byte array and vice versa. This method is very useful when we need to perform other operations on the byte array using the methods provided by the ByteBuffer class.

Example

import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.util.Arrays;

public class StringToByteArray {
   public static void main(String[] args) {
      String str = "Hello, world!";
      Charset charset = Charset.forName("UTF-8");
      ByteBuffer byteBuffer = charset.encode(str);
      byte[] byteArray = byteBuffer.array();
      System.out.println("Byte array using ByteBuffer class: " + Arrays.toString(byteArray));
   }
}

Output

Byte array using ByteBuffer class: [72, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100, 33, 0]

in conclusion

In summary, converting a string to a byte array in Java can be achieved through the "getBytes()" method. There are two methods, one using the default character set encoding and the other using a specific character set encoding. The choice of method depends on the application requirements. The "ByteBuffer" class can also be used for this conversion, using the "Charset" class to specify the encoding. We provide detailed code examples and output for each method.

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