.使用TreeSet集合生成一个不重复随机数组，该数组包含10个100以内的随机整数。输出该随机数组。 

 import java.util.Iterator;

 import java.util.TreeSet;

 public class Test {

     public static void main(String[] args) {

         int x;

         int arr []=new int [];

         TreeSet<Integer> set =new TreeSet<Integer>();

         int d=;

         while(d<){

             x=(int)(Math.random()*);

             if(set.add(x))//TreeSet是去重复的集合，集合中没有的返回true

                 d++;

         }

         /*

          while(set.size()<10){

             x=(int)(Math.random()*100);

            set.add(x);

         }

          */

         int i=;

         Iterator<Integer>it=set.iterator();

         while(it.hasNext()){

             int t=it.next();

             arr[i]=t;

             i++;

         }

         for(i=;i<=;i++)

             System.out.print(arr[i]+" ");

     }

 }

 .创建一个Student类，使用比较器Comparator，根据学号进行对象排序。

 import java.util.Comparator;

 import java.util.Iterator;

 import java.util.TreeSet;

 class Student {

     private String name;

     private String id;

     public Student(){

     }

     public Student(String name,String id){

         this.name=name;

         this.id=id;

     }

     public String getName() {

         return name;

     }

     public String getId() {

         return id;

     }

 }

 class DescSort implements Comparator<Student> {

     public int compare(Student s1, Student s2) {

         if(s1.getId().compareTo(s2.getId())>)

             return -;

         else if(s1.getId().compareTo(s2.getId())<)

             return ;

         else return ;

     }

 }

 public class Test {

     public static void main(String[] args)   {

     Comparator<Student> comp=new DescSort();

     TreeSet<Student> t=new TreeSet<Student>(comp);

     t.add(new Student("小赵",""));

     t.add(new Student("小王",""));

     t.add(new Student("小明",""));

     t.add(new Student("小红",""));

     t.add(new Student("小李",""));

     Iterator<Student>it=t.iterator();

     while(it.hasNext()){

         Student stu=it.next();

         System.out.println(stu.getName()+"的学号是"+stu.getId());

     }

 }

 }