截取字符串中某些字符

public class test
{
	public static void main(String[] args) {
		String s = "ABCDEFG";
		String s1 = null;
		s1 = s.replaceAll("CD", "");
		System.out.println(s1);
		String s2 = s1.replaceAll("B|F", "");
		System.out.println(s2);
	}
}