java - 如何从输入生成随机值？

Question

我正在寻找一种根据种子的给定输入生成随机值的方法。我将给出一个代码示例来说明我想要实现的目标:

public class Seed {

  public double generateRandom(double input) {
    // What goes in here?
  }

}

示例程序如下所示:

public static void main(String[] args) {
  Seed seed1 = new Seed(), seed2 = new Seed();

  System.out.println("Result of seed 1 with 69: " + seed1.generateRandom(69));
  System.out.println("Result of seed 2 with 69: " + seed2.generateRandom(69));
  System.out.println("Result of seed 1 with 420: " + seed1.generateRandom(420));
  System.out.println("Result of seed 2 with 420: " + seed2.generateRandom(420));

  System.out.println("Result of seed 1 with 69 is still: " + seed1.generateRandom(69));
  System.out.println("Result of seed 2 with 69 is still: " + seed2.generateRandom(69));
}

输出为:

Result of seed 1 with 69: 0.5
Result of seed 2 with 69: 0.65
Result of seed 1 with 420: 0.2
Result of seed 2 with 420: 0.34
Result of seed 1 with 69 is still: 0.5
Result of seed 2 with 69 is still: 0.65

Seed 类会是什么样子？

Answer 1

嗯，示例实现可能类似于:

public class Seed {

  private long seed = new Random().nextLong();

  public double generateRandom(long input) {
      return new Random(seed + input).nextDouble();
  }
}

注意本实现中generateRandom的参数是long。