Java 无效的转义序列（有效的是 \b \t \n \f \r \" \' \ ）
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Invalid escape sequence (valid ones are \b \t \n \f \r \" \' \ )
提问by Annika
I have a problem with a regex in java.
我在 java 中的正则表达式有问题。
When I try to use this regex:
当我尝试使用这个正则表达式时：
^(?:(?:([01]?\d|2[0-3]):)?([0-5]?\d):)?([0-5]?\d)$
I get the following error
我收到以下错误
"Invalid escape sequence (valid ones are \b \t \n \f \r \" \' \ )"
I don't know how to handle that error. I already tried to double the backslashes, but it didn't work. I hope someone can help me with this.
我不知道如何处理那个错误。我已经尝试将反斜杠加倍，但没有用。我希望有人能帮我解决这个问题。
Thanks
谢谢
采纳答案by Uku Loskit
This should work ^(?:(?:([01]?\\d|2[0-3]):)?([0-5]?\\d):)?([0-5]?\\d)$
这应该工作 ^(?:(?:([01]?\\d|2[0-3]):)?([0-5]?\\d):)?([0-5]?\\d)$
The reason is that the listed symbols in the error message have special meaning, but \dis not one of those defined special symbols for using \, this means you have to escape it (by adding an extra \in front of the symbol).
原因是错误消息中列出的符号具有特殊含义，但\d不是用于 using 的那些定义的特殊符号之一\，这意味着您必须对其进行转义（通过\在符号前添加额外的符号）。
回答by óscar López
Whenever you're writing regular expressions in Java, remember to escape the \characters used in the string that defines the regular expression. In other words, if your regular expression contains one \, then you HAVE to write two \\. For example, your code should look like this:
每当您在 Java 中编写正则表达式时，请记住对\定义正则表达式的字符串中使用的字符进行转义。换句话说，如果您的正则表达式包含一个\，那么您必须编写两个\\。例如，您的代码应如下所示：
^(?:(?:([01]?\d|2[0-3]):)?([0-5]?\d):)?([0-5]?\d)$
Why, you ask? because in Java's strings, \is the escape character used to denote special characters (example: tabs, new lines, etc.) and if a string contains a \then it must itself be escaped, by prepending another \in front of it. Hence, \\.
你为什么问？因为在 Java 的字符串中，\是用于表示特殊字符（例如：制表符、换行符等）的转义字符，如果字符串包含 ，\那么它本身必须通过\在它前面加上另一个来转义。因此，\\。
For the record, hereis the Java language specification page listing the valid escape characters and their meanings, notice the last one:
作为记录，这里是 Java 语言规范页面，列出了有效的转义字符及其含义，注意最后一个：
\b backspace
\t horizontal tab
\n linefeed
\f form feed
\r carriage return
\" double quote
\' single quote
\ backslash
回答by sfblap
you can use notepad++ with find / and replace with //
您可以将记事本++与 find / 一起使用并替换为 //
