How to Convert a String value to Byte value in Java with Examples

Given a String “str” in Java, the task is to convert this string to byte type.

Examples:

Input: str = "1"
Output: 1

Input: str = "3"
Output: 3

Approach 1: (Naive Method)
One method is to traverse the string and add the numbers one by one to the byte type. This method is not an efficient approach.

Approach 2: (Using Byte.parseByte() method)
The simplest way to do so is using parseByte() method of Byte class in java.lang package. This method takes the string to be parsed and returns the byte type from it. If not convertible, this method throws error.

Syntax:

Byte.parseByte(str);

Below is the implementation of the above approach:

Example 1: To show successful conversion

// Java Program to convert string to byte

class GFG {

    // Function to convert String to Byte
    public static byte convertStringToByte(String str)
    {

        // Convert string to byte
        // using parseByte() method
        return Byte.parseByte(str);
    }

    // Driver code
    public static void main(String[] args)
    {

        // The string value
        String stringValue = "1";

        // The expected byte value
        byte byteValue;

        // Convert string to byte
        byteValue = convertStringToByte(stringValue);

        // Print the expected byte value
        System.out.println(
            stringValue
            + " after converting into byte = "
            + byteValue);
    }
}

Output:

1 after converting into byte = 1

Approach 3: (Using Byte.valueOf() method)
The valueOf() method of Byte class converts data from its internal form into human-readable form.

Syntax:

Byte.valueOf(str);

Below is the implementation of the above approach:

Example 1: To show successful conversion

// Java Program to convert string to byte

class GFG {

    // Function to convert String to Byte
    public static byte convertStringToByte(String str)
    {

        // Convert string to byte
        // using valueOf() method
        return Byte.valueOf(str);
    }

    // Driver code
    public static void main(String[] args)
    {

        // The string value
        String stringValue = "1";

        // The expected byte value
        byte byteValue;

        // Convert string to byte
        byteValue = convertStringToByte(stringValue);

        // Print the expected byte value
        System.out.println(
            stringValue
            + " after converting into byte = "
            + byteValue);
    }
}

Output:

1 after converting into byte = 1