Java 是否存在不被视为空白的不可见字符？
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原文地址: http://stackoverflow.com/questions/19936374/
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Is there an invisible character that is not regarded as whitespace?
提问by CodeBlue
I am working with an existing framework where I have to set a certain attribute to blank if some conditions are satisfied. Unfortunately, the framework doesn't allow setting only whitespace to the attribute value. Specifically, it does a
我正在使用现有框架，如果满足某些条件，我必须将某个属性设置为空白。不幸的是，该框架不允许只为属性值设置空格。具体来说，它做了一个
!(org.apache.commons.lang.StringUtils.isBlank(value))check on the value
!(org.apache.commons.lang.StringUtils.isBlank(value))检查值
Is it possible to somehow bypass this and set a value that looks blank/invisible to the eye but is not regarded as whitespace?
是否有可能以某种方式绕过它并设置一个看起来空白/肉眼不可见但不被视为空白的值？
I am using a dash "-" right now, but I think it would be interesting to know if it's possible.
我现在正在使用破折号“-”，但我认为知道是否可能会很有趣。
采纳答案by Michael Konietzka
Try Unicode Character 'ZERO WIDTH SPACE' (U+200B). It is not a Whitespace according to WP: Whitespace#Unicode
试试Unicode 字符“零宽度空间”（U+200B）。根据WP，它不是空格：Whitespace#Unicode
The code of StringUtils.isBlankwill not bother it:
StringUtils.isBlank的代码不会打扰它：
public static boolean isBlank(String str) {
int strLen;
if (str == null || (strLen = str.length()) == 0) {
return true;
}
for (int i = 0; i < strLen; i++) {
if ((Character.isWhitespace(str.charAt(i)) == false)) {
return false;
}
}
return true;
}
回答by Bugs Bunny
That Unicode Character 'ZERO WIDTH SPACE' (U+200B) Michael Konietzka shared didn't work for me, but found a different one that did:
Michael Konietzka 共享的那个 Unicode 字符“零宽度空间”（U+200B）对我不起作用，但发现了一个不同的字符：
??? ?
??? ?
It actually identifies as combination of
它实际上标识为的组合
U+200F : RIGHT-TO-LEFT MARK [RLM]
U+200F : RIGHT-TO-LEFT MARK [RLM]
U+200E : LEFT-TO-RIGHT MARK [LRM]
U+0020 : SPACE [SP]
U+200E : LEFT-TO-RIGHT MARK [LRM]
and it's ASCII value is 8207
它的 ASCII 值是 8207
???'??? ?'.charCodeAt(0) // 8207
???'??? ?'.charCodeAt(0) // 8207
Source: http://emptycharacter.com/
回答by M. I. Wright
There's also ?(U+2800 BRAILLE PATTERN BLANK), which is a blank Braille block rather than a space character.
还有?(U+2800 BRAILLE PATTERN BLANK)，这是一个空白的盲文块而不是空格字符。
