import java.io.*;
import java.util.*;

class Keyadd{
public static void main(String args[]) throws Exception {

Set<Integer> numbers = new TreeSet<Integer>();
System.out.println("请输入整数,输入end结束输入:");
BufferedReader re = new BufferedReader(new InputStreamReader(System.in));
String s = "";
while (!(s = re.readLine()).equals("end")) {
int num = new Integer(s);
numbers.add(num);

}
System.out.println("您输入了:"+numbers.size()+"个数字!");
System.out.println(numbers);


}
}

------解决方案--------------------
恩，TreeSet就可以但是Set里不许有重复的元素，用的时候注意