Apache Commons Text:特殊字符java的随机字符串 [英] Apache Commons Text: Random String for special characters java

问题描述

我正在使用apache commons-text:RandomStringGenerator生成随机String，如下所示:

I'm using apache commons-text:RandomStringGenerator for generating a random String like so:

//Utilities
private static RandomStringGenerator generator(int minimumCodePoint, int maximumCodePoint, CharacterPredicates... predicates) {
    return new RandomStringGenerator.Builder()
            .withinRange(minimumCodePoint, maximumCodePoint)
            .filteredBy(predicates)
            .build();
}

public static String randStringAlpha(int length) {
    return generator('A', 'z', CharacterPredicates.LETTERS).generate(length);
}

public static String randStringAlphaNum(int length) {
    return generator('1', 'z', CharacterPredicates.LETTERS, CharacterPredicates.DIGITS).generate(length);
}

//Generation
private void foo() {
    String alpha = randStringAlpha(255);
    String num = randStringAlphaNum(255);
}

我正在寻找一种使用相同库生成以下内容的方法:

A-特殊字符(可以限于键盘特殊字符)

B-字母+ A

C-num + A

D-字母+数字+ A

I'm looking for a way to use the same library to generate to following:

A - special characters (could be limited to keyboard special characters)

B - alpha + A

C - num + A

D - alpha + num + A

我已经检查过CharacterPredicates enum，但是它只包含LETTERS和DIGITS进行过滤.任何帮助将不胜感激！

I already checked the CharacterPredicates enum but it only has LETTERS and DIGITS for filtering. Any help would be really appreciated!

我决定采用目前的解决方案，以支持此答案.
为了阐明特殊字符"的范围，我实际上是在寻找该子集:

I decided to shelf my current solution in favor of this answer.
To clarify the scope of 'special characters' I was actually looking for this subset:

案例A的摘要:

public static CharSequence asciiSpecial() {
    return asciiCharacters().toString().replaceAll("(\\d|[A-z])","");
}

推荐答案

您的类别特殊字符"非常模糊.只要您停留在ASCII范围内，所有字符都是字母，数字或特殊"字符，但是可以使用普通键盘输入.换句话说，您完全不需要为此指定过滤器.另一方面，当您离开ASCII范围时，您将需要处理多种字符类别(例如，您不想在任意点插入随机组合字符)，此外，没有通用的测试可以使用键盘输入字符(因为没有通用键盘)…

Your category "special characters" is quiet fuzzy. As long as you stay with the ASCII range, all characters are either letter, digit or "special", but can be entered with an ordinary keyboard. In other words, you don’t need to specify a filter at all for that. On the other hand, when you leave the ASCII range, there is a variety of character categories you would have to care of (e.g. you don’t want to insert random combining characters at arbitrary points), further, there is no general test whether a character can be entered with a keyboard (as there is no general keyboard)…

但是请注意，尝试使用该库的代码已经比执行实际工作的代码大.例如.要获得随机字母字符串，可以使用

But note that your code trying to use that library is already bigger than code doing the actual work would be. E.g. to get a random letter string, you could use

public static String randStringAlpha(int size) {
    return ThreadLocalRandom.current().ints('A', 'z'+1)
        .filter(Character::isLetter)
        .limit(size)
        .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
        .toString();
}

或更有效的变体

public static String randStringAlpha(int size) {
    return ThreadLocalRandom.current().ints(size, 'A', 'Z'+1)
        .map(c -> ThreadLocalRandom.current().nextBoolean()? c: Character.toLowerCase(c))
        .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
        .toString();
}

没有任何第三方库.

同样，您可以使用来概括该任务

Likewise, you could generalize the task using

public static String randomString(int size, CharSequence validChars) {
    return ThreadLocalRandom.current().ints(size, 0, validChars.length())
        .map(validChars::charAt)
        .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
        .toString();
}
public static String randomString(int minSizeIncl, int maxSizeIncl, CharSequence valid) {
    return randomString(
        ThreadLocalRandom.current().nextInt(minSizeIncl, maxSizeIncl), valid);
}
public static CharSequence asciiLetters() {
    return IntStream.concat(IntStream.rangeClosed('A','Z'), IntStream.rangeClosed('a','z'))
        .collect(StringBuilder::new,StringBuilder::appendCodePoint,StringBuilder::append);
}
public static CharSequence asciiLetterOrDigit() {
    return IntStream.concat(asciiLetters().chars(),IntStream.rangeClosed('0', '9'))
        .collect(StringBuilder::new,StringBuilder::appendCodePoint,StringBuilder::append);
}
public static CharSequence asciiCharacters() {
    return IntStream.rangeClosed('!', '~')
        .collect(StringBuilder::new,StringBuilder::appendCodePoint,StringBuilder::append);
}

您可以将两种方法结合使用，例如
RandomString.randomString(10, asciiLetters())，
RandomString.randomString(10, asciiLetterOrDigit())或
RandomString.randomString(10, asciiCharacters())，分别.他们的可变尺寸对象如RandomString.randomString(10, 20, asciiCharacters()).

Which you can use by combining two methods, e.g.
RandomString.randomString(10, asciiLetters()),
RandomString.randomString(10, asciiLetterOrDigit()), or
RandomString.randomString(10, asciiCharacters()), resp. their variable-size counterparts like RandomString.randomString(10, 20, asciiCharacters()).

CharSequence可以在多个字符串生成调用之间重用，类似于构建RandomStringGenerator并多次使用.

The CharSequences can be reused between multiple string generation calls, would be similar to building a RandomStringGenerator and using it multiple times.

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