Changing the Case of Characters Within a String - Java

Changing the Case of Characters Within a String

The method toLowerCase( ) converts all the characters in a string from uppercase to lowercase. The toUpperCase( ) method converts all the characters in a string from lowercase to uppercase. Nonalphabetical characters, such as digits, are unaffected. Here are the simplest forms of these methods:

String toLowerCase( ) String toUpperCase( )

Both methods return a String object that contains the uppercase or lowercase equivalent of the invoking String. The default locale governs the conversion in both cases.

Here is an example that uses toLowerCase( ) and toUpperCase( ):

// Demonstrate toUpperCase() and toLowerCase().

class ChangeCase {

public static void main(String args[])

{

String s = "This is a test.";

System.out.println("Original: " + s);

String upper = s.toUpperCase();

System.out.println("Uppercase: " + upper); System.out.println("Lowercase: " + lower);

}

}

The output produced by the program is shown here:

Original: This is a test.

Uppercase: THIS IS A TEST.

Lowercase: this is a test.

One other point: Overloaded versions of toLowerCase( ) and toUpperCase( ) that let you specify a Locale object to govern the conversion are also supplied. Specifying the locale can be quite important in some cases and can help internationalize your application.