Parse amount field using regular expression

I have an HTML input field for entering an amount. It must be 1 to 20 digits, optionally followed by up to 10 decimal digits, and optionally ending with "k" or "m" to denote the thousand or million respectively. So "123.12k" would be parsed as 123120. The following is a JavaScript solution previously provided by Tim Yates:

function mFunc( sVal )
{
    var elems = sVal.match( /^(\d{1,20}(\.\d{0,10})?)([k|m])?$/ ) ;
    if( elems )
    {
        var num = elems[ 1 ] ;
        var mult = elems[ 3 ] ;
        if( mult == 'k' )
        {
            num *= 1000 ;
        }
        else if( mult == 'm' )
        {
            num *= 1000000 ;
        }
        alert( 'value is ' + num ) ;
    }
    else
    {
        alert( 'invalid number' ) ;
    }
}

Now I need the equivalent function in Java. Thanks!