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

Java programming involves string to byte array conversion, a convenient technique used for many purposes, including network communication or data encryption. To achieve this, the String class provides a series of methods for such conversions, and the getBytes() method is one of them. It's worth noting that choosing the appropriate encoding is critical, as each encoding applies different rules when mapping characters to byte values.

In this article, we will delve into two techniques for converting a string into a byte array using Java’s getBytes() method. Furthermore, we will provide an extensive explanation of the algorithms employed by each method.

usage instructions

• Method 1 - In this method we will create a string and then convert it into a byte array using getBytes() method. We will use UTF-8 encoding in this example.

• Method 2 - In this method we will create a byte array by specifying the byte values ​​manually. We will then create a String from the byte array using the String constructor.

grammar

The getBytes() method is a member of the String class in Java. It takes one argument, which is the character set used to encode the string into a byte array. The syntax of the getBytes() method is as follows -

public byte[] getBytes(Charset charset)

algorithm

The method of converting a string into a byte array using the getBytes() function in Java can be simplified into a few steps -

• Step 1 - Instantiate the Charset object corresponding to the desired encoding using the forName() method in the Charset class. This step requires providing the encoding name as a string parameter.

• Step 2 - Call the getBytes() method of the String class, providing the previously created Charset object as a parameter. This call generates a byte array representing the characters in the string using the specified encoding.

• Step 3 - Manipulate the resulting byte array as needed. Java provides various techniques for handling byte arrays through its programming language.

Utilizing the getBytes() function is an effective way to convert a string into a Java byte array. It enables you to specify the encoding to be used during conversion. This is crucial because different encodings have different guidelines for mapping characters to byte values. If you use the wrong encoding, data corruption may occur. By following the algorithm above, they can ensure that their String is successfully and safely converted to a byte array.

method 1

In this method, we first create a string that we wish to convert to a byte array. Then, we convert the String into a byte array using the getBytes() method of the String class. We define the encoding to be applied to the conversion, in this case UTF-8. To ensure that the byte array is generated accurately, we print it out.

Below is the same program code.

Example

import java.nio.charset.Charset;

public class StringToByteArrayExample1 {
   public static void main(String[] args) {
      // Create a String
      String str = "Hello, world!";
        
      // Convert the String to a byte array using the UTF-8 encoding
      Charset utf8 = Charset.forName("UTF-8");
      byte[] byteArray = str.getBytes(utf8);
       
      // Print the byte array
      for (byte b : byteArray) {
         System.out.print(b + " ");
      }
   }
}

Output

72 101 108 108 111 44 32 119 111 114 108 100 33

Method 2

This method involves manually entering byte values ​​to construct a byte array. Then use the String constructor to convert the byte array to a String.

Below is the same program code.

Example

import java.nio.charset.Charset;

public class StringToByteArrayExample2 {
   public static void main(String[] args) {
      // Create a byte array
      byte[] byteArray = {72, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100, 33};
        
      // Convert the byte array to a String using the UTF-8 encoding
      Charset utf8 = Charset.forName("UTF-8");
      String str = new String(byteArray, utf8);
        
      // Print the String
      System.out.println(str);
   }
}

Output

Hello, world!

in conclusion

This article introduces the containsKey() function, which is used to determine whether a key is contained in the hash map. This method accepts a key as input and returns true if the key is found in the hashmap; otherwise, returns false.

The above is the detailed content of Convert string to byte array using getBytes(Charset) method in Java. For more information, please follow other related articles on the PHP Chinese website!