将list集合，元素随机打乱

 

• for循环+随机数 实现相同位置的元素交换

• public <T> void shuffle(List<T> list) {
          int size = list.size();
          Random random = new Random();
  
          for(int i = 0; i < size; i++) {
  
              int randomPos = random.nextInt(size);
  
              T temp = list.get(i);
              list.set(i, list.get(randomPos));
              list.set(randomPos, temp);
          }
      }

• Collections.swap实现

• public <T> void shuffle(List<T> list) {
          int size = list.size();
          Random random = new Random();
  
          for(int i = 0; i < size; i++) {
  
              int randomPos = random.nextInt(size);
  
              Collections.swap(list, i, randomPos);
          }
      }

  Collections.shuffle实现

• public <T> void shuffle(List<T> list)
   { 
  Collections.shuffle(list); 
  }