生成范围内的每个随机数

Question

I want to get EVERY random number within a certain range exactly once.

For example, if the range was 1-10, I would want every number 1-10 in a random order. What is a simple, fast, and clean algorithm for doing this?

Is there some existing way to do this automatically in Java?

Answer 1

填充一个包含1-10之间数字的列表，然后使用Collections.shuffle(list);

Answer 2

There's no way from the JDK, but the simplest approach is to use Collections.shuffle() on a list of all the numbers in the range:

List<Integer> list = new ArrayList<>();
for (int i = 1; i < 11; i++) list.add(i);
Collections.shuffle(list);

then return the contents of list in order