Convert String to Byte Array in Java Using getBytes(Charset) Method
Last Updated :
22 Nov, 2024
To convert a string to a byte array, we use the getBytes(Charset) method In Java that transforms the string into a sequence of bytes based on a specified character encoding. This method returns the byte array and relies on the Charset class to handle character-to-byte mappings.
Example:
Java
// Java program to convert a String to a byte array
// using getBytes(Charset) method with UTF-8 encoding
import java.nio.charset.StandardCharsets;
public class StringToByteArray {
public static void main(String[] args) {
// sample string
String s = "hello";
// Convert string to byte array using UTF-8 encoding
byte[] b = s.getBytes(StandardCharsets.UTF_8);
// Print the byte array
for (byte b1 : b) {
System.out.print(b1 + " ");
}
}
}
Output104 101 108 108 111
Explanation: The above program converts the string "hello" into a byte array using UTF-8 encoding by using the getBytes(StandardCharsets.UTF_8) method. Then it prints each byte of the resulting byte array.
Syntax of getBytes(Charset) Method
byte[] byteArray = string.getBytes(Charset charset);
Parameter: charset is the character set used to encode the string. For example, StandardCharsets.UTF_8 or Charset.forName("UTF-8").
Return type: This function returns the resulting byte array.
Important Points:
- This method always replaces malformed input and unmappable character sequence with its charset's default replacement byte array.
- If the given charset is not a valid charset, then this method will throw UnsupportedEncodingException.
- The length of the byte array is not the same as the given string, it depends upon the character encoding.
Other Ways to Convert a String to Byte Array Using getBytes(Charset)
1. Convert String to Byte Array Using UTF-16 Charset
Example:
Java
// Java Program to illustrate how to
// convert a string to byte array
// Using getBytes(Charset charset)
import java.io.*;
class GFG {
public static void main (String[] args) {
String s = "Hello GeeksforGeeks";
// Display the string before conversion
System.out.println("String: " + s);
try {
// Converting string to byte array
// Using getBytes(Charset charset) method
// Here, we convert the string into UTF-16 values
byte[] r = s.getBytes("UTF-16");
// Displaying the converted string after
// conversion into UTF-16
System.out.println("Result: ");
for (int i = 0; i < r.length; i++) {
System.out.print(r[i] + " ");
}
} catch (Exception e) {
System.out.println("Error: " + e);
}
}
}
OutputString: Hello GeeksforGeeks
Result:
-2 -1 0 72 0 101 0 108 0 108 0 111 0 32 0 71 0 101 0 101 0 107 0 115 0 102 0 111 0 114 0 71 0 101 0 101 0 107 0 115
Explanation: The above example converts the string "Hello GeeksforGeeks" into a byte array using the UTF-16 charset with the getBytes("UTF-16") method. Then it prints each byte of the resulting byte array to the console.
2. Convert String to Byte Array Using US-ASCII Charset
Example:
Java
// Java Program to illustrate how to
// convert a string to byte array
// Using getBytes(Charset charset)
import java.io.*;
import java.util.Arrays;
class GFG{
public static void main (String[] args)
{
String s1 = "Hello GFG";
// Display the string before conversion
System.out.println("String: " + s1);
try
{
// Converting string to byte array
// Using getBytes(Charset charset) method
// Here, we converts into US-ASCII values
byte[] r = s1.getBytes("US-ASCII");
// Displaying converted string after conversion
// into US-ASCII
System.out.println("Byte Array: " + Arrays.toString(r));
}
catch (UnsupportedEncodingException g)
{
System.out.println("Unsupported character set" + g);
}
}
}
OutputString: Hello GFG
Byte Array: [72, 101, 108, 108, 111, 32, 71, 70, 71]
Explanation: The above example converts the string "Hello GFG" into a byte array using the US-ASCII charset with the getBytes("US-ASCII") method. Then it prints the resulting byte array using Arrays.toString() to display the ASCII values of the characters.