How to convert a byte array to a String and back to a byte array in Java?

Byte Array to String and Back to Byte Array in Java

Suppose you have an initial byte[] array and need to convert it to a string representation. Subsequently, you want to convert that string back into a byte[] array. This conversion is essential for data transmission and processing in various scenarios.

To convert a byte[] array into a string, you can use the Arrays.toString() method. This method returns a string that represents the content of the byte[] array. However, it's important to note that this string is not a byte[] array anymore. It is a string representation of the byte[] array.

After sending the string over the wire, the receiving end attempts to convert the received string back into a byte[] array. Here is the challenge: the string is no longer a byte[] array; it is a string with a specific format.

To convert the received string back into a byte[] array, you can use the following approach:

1. Parse the String: Read the string character by character and extract the numerical value of each byte.

String response = "[-47, 1, 16, 84, 2, 101, 110, 83, 111, 109, 101, 32, 78, 70, 67, 32, 68, 97, 116, 97]";

String[] byteValues = response.substring(1, response.length() - 1).split(",");

2. Create Byte Array: Allocate a new byte[] array with the appropriate length.

byte[] bytes = new byte[byteValues.length];

3. Assign Byte Values: Loop through each parsed byte value and assign it to the corresponding element in the byte[] array.

for (int i = 0, len = bytes.length; i < len; i++) {
    bytes[i] = Byte.parseByte(byteValues[i].trim());
}

4. Return Byte Array: The bytes array contains the original byte data.

By following this approach, you can effectively convert a byte[] array to a string, send it over the wire, and then convert it back to a byte[] array on the receiving side. This conversion is essential for data manipulation and communication, ensuring that you can work with byte[] arrays throughout the workflow while maintaining the integrity of the data.

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