TreeSet去重字符串

public class TreeSetTest {


	public static void main(String[] args) {
		TreeSet tr = new TreeSet();
		String[] s = { "11", "22", "22", "33", "33", "33" };
		System.out.print("====处理前=======");
		for (int i = 0; i < s.length; i++) {
			System.out.print(s[i] + " ");
			tr.add(s[i]);


		}
		String[] s2 = new String[tr.size()];
		System.out.println("=====处理后======");
		for (int i = 0; i < s2.length; i++) {
			s2[i] = tr.pollFirst();// 从TreeSet中取出元素重新赋给数组  //tr.pollFirst()这一步执行后 tr.size 为空 应该是清空了 tr
			System.out.print(s2[i] + " ");
		}
		if(tr.contains("11")){
			System.out.print(11);//这里不会打印输出 contans不能这么用 
			 //tr.pollFirst()这一步执行后 tr.size 为空 应该是清空了 tr
		}
}