List集合对象中的排序，随机显示

  List<User> students = new ArrayList<User>();  

          User user1 = new User();
          user1.setAge(112);
          user1.setUserName("小米");
          user1.setMoney(118.55);
          students.add(user1);  

          User user2 = new User();
          user2.setAge(82);
          user2.setUserName("小王");
          user2.setMoney(88.55);
          students.add(user2); 

          User user3 = new User();
          user3.setAge(100);
          user3.setUserName("小李");
          user3.setMoney(110.65);
          students.add(user3); 

          User user4 = new User();
          user4.setAge(99);
          user4.setUserName("小赵");
          user4.setMoney(99.5);
          students.add(user4); 

             Collections.sort(students, new Comparator<User>() {
                   @Override
                 public int compare(User o1, User o2) {
                       //降序
                       /*if(o1.getMoney()>o2.getMoney()){
                           return -1;
                       }
                       if(o1.getMoney()<o2.getMoney()){
                           return 1;
                       }
                       return 0;*/

                       //升序
                           if(o1.getMoney()>o2.getMoney()){
                               return 1;
                           }
                           if(o1.getMoney()<o2.getMoney()){
                               return -1;
                           }
                           return 0;

                      /*int i = o1.getAge() - o2.getAge();
                      return i;*/
                 }
             });
             for(User stu : students){
                 System.out.println("score:" + stu.getUserName() + ":age:" + stu.getAge()+":money:"+stu.getMoney());
             }  

简单类型list排序

 List<Integer> nums = new ArrayList<Integer>();
         nums.add(3);
         nums.add(5);
         nums.add(1);
         nums.add(0);
         System.out.println(nums);
         Collections.sort(nums);
         System.out.println(nums);

list集合随机显示（实体类）

  List<Integer> list = new ArrayList<Integer>();
             for (int i = 0; i < 5; i++) {
                 list.add(i);
             }
             Collections.shuffle(list);
             for(Integer yy:list){
                  System.out.println("随机："+yy);
             }