问题
I need to test out a Java program 20 times and need to set the random seed so that the tests can be repeated. If I were to set the initial seed as 0 and then increment by 1 at each run (i.e. 1,2,3 etc), would this method still ensure complete randomness, even though the seeds are not far apart?
Thank you
回答1:
Any seed will provide the same level of randomness as any other seed for a standard PRNG like the one included with Java. So it's fine to use an incrementing seed for tests.
You might want to consider using a better random number generator though. The one included with Java yields noticeable repeating patterns if you render the values as an image (I can't find a reference offhand, but I recall it being apparent). I'd recommend the Mersenne Twister (there are Java versions) as an alternative that's fast and has a very long period so you won't easily see patterns.
回答2:
If you use a seed of 0 the sequence of random numbers will be repeatable from that point. You would only need to use a different random seed if you wanted a different sequence. i.e. you should be able to set the seed once per test.
回答3:
Why not just use the current time as the seed? ie, System.currentTimeMillis() ?
回答4:
Do you need a number or a string? I use UUID.randomUUID().toString() to get a UUID for my tests when I need strings, but if you need a number then you can use System.nanoTime().
来源：https://stackoverflow.com/questions/5799179/java-random-seed