写一个正则表达式，匹配10000以内的数字，可能带两位小数，也可能不带

public class Test02 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String er = "\\d{1,4}(\\.\\d{2})?";
		System.out.println("9999.99".matches(er));
		System.out.println("18".matches(er));
		System.out.println("673.02".matches(er));
		System.out.println("0.99".matches(er));
		System.out.println("*********************");
		System.out.println("9999.999".matches(er));
		System.out.println("10000".matches(er));
		System.out.println("456.".matches(er));
		System.out.println(".99".matches(er));
	}