是否有在 Java 中生成随机字符的功能? [英] Is there functionality to generate a random character in Java?

问题描述

Java 是否具有生成随机字符或字符串的功能?还是必须简单地选择一个随机整数并将该整数的 ascii 代码转换为字符?

Does Java have any functionality to generate random characters or strings? Or must one simply pick a random integer and convert that integer's ascii code to a character?

推荐答案

有很多方法可以做到这一点，但是是的，它涉及生成一个随机的 int(例如使用 java.util.Random.nextInt)然后使用它来映射到 char.如果你有一个特定的字母表，那么像这样的东西很不错:

There are many ways to do this, but yes, it involves generating a random int (using e.g. java.util.Random.nextInt) and then using that to map to a char. If you have a specific alphabet, then something like this is nifty:

    import java.util.Random;

    //...

    Random r = new Random();

    String alphabet = "123xyz";
    for (int i = 0; i < 50; i++) {
        System.out.println(alphabet.charAt(r.nextInt(alphabet.length())));
    } // prints 50 random characters from alphabet

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请注意，java.util.Random 实际上是一个 伪-随机数生成器基于相当弱的线性同余公式.你提到了密码学的必要性；在这种情况下，您可能想要调查使用更强大的密码安全伪随机数生成器(例如java.security.SecureRandom).

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Do note that java.util.Random is actually a pseudo-random number generator based on the rather weak linear congruence formula. You mentioned the need for cryptography; you may want to investigate the use of a much stronger cryptographically secure pseudorandom number generator in that case (e.g. java.security.SecureRandom).

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