Java：如何实现Treeset的查找功能，请帮我增加查找功能代码

package test3;
import java.util.Iterator;
import java.util.TreeSet;
public class myset {
public static void main( String [] args ) {
TreeSet set = new TreeSet();
System.out.println("-添加-");
set.add(2); // 添加
set.add(7);
set.add(5);
set.add(9);
set.add(2);
Iterator it = set.iterator();

while (it.hasNext()){
    Integer num = it.next();
    System.out.println(num);
}

System.out.println("-删除-");
set.remove(3);
System.out.println(set);

}}