String.replace所有单反斜杠为双反斜杠
我正在尝试使用 String \something\ 转换为 String \\something\\ >replaceAll，但我不断收到各种错误。我认为这就是解决方案：
theString.replaceAll("\\", "\\\\");
但这给出了以下例外：
java.util.regex.PatternSyntaxException: Unexpected internal error near index 1
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String#replaceAll()将参数解释为 正则表达式。\是两者String和regex中的转义字符。您需要对正则表达式进行双重转义：但您不一定需要正则表达式，只是因为您想要精确的逐个字符替换，并且这里不需要模式。所以
String#replace()应该足够了：更新：根据注释，您似乎想要在 JavaScript 上下文中使用该字符串。你也许最好使用
StringEscapeUtils#escapeEcmaScript()而是覆盖更多字符。The
String#replaceAll()interprets the argument as a regular expression. The\is an escape character in bothStringandregex. You need to double-escape it for regex:But you don't necessarily need regex for this, simply because you want an exact character-by-character replacement and you don't need patterns here. So
String#replace()should suffice:Update: as per the comments, you appear to want to use the string in JavaScript context. You'd perhaps better use
StringEscapeUtils#escapeEcmaScript()instead to cover more characters.TLDR：使用
theString = theString.replace("\\", "\\\\");代替。问题
replaceAll(target, replacement)对target使用正则表达式 (regex) 语法，部分对replacement使用。问题是
\是正则表达式中的特殊字符（它可以像\d一样使用来表示数字）和字符串文字（它可以像"\ n"表示行分隔符，或\"转义双引号符号，双引号符号通常表示字符串文字的结尾，在这两种情况下都创建
\符号 。我们可以通过在其前面放置额外的\来转义它（使其成为文字而不是特殊字符）（就像我们通过 < 在字符串文字中转义"一样） code>\")。因此，对于表示
\符号的target正则表达式，需要保存\\，而表示此类的字符串文字文本需要看起来像"\\\\"所以我们转义了
\两次：\\\表示为"\\"）。 code>\ 也很特殊，它允许我们转义其他特殊字符
$，通过$x表示法，允许我们使用与 匹配的数据部分。正则表达式并由索引为x的捕获组保存，例如"012".replaceAll("(\\d)", "$1$1")将匹配每个数字、位置它在捕获组 1 中，$1$1将用它的两个副本替换它（它将复制它），从而产生“001122”。再次强调，要让
replacement代表\文字，我们需要使用额外的\对其进行转义，这意味着：\\\\的字符串文字看起来像"\\\\"但因为我们希望
replacement保存两个个反斜杠，我们需要"\\\\\\\\"（每个\由一个"\\\\ “）。因此，使用
replaceAll的版本看起来像使用
replaceAll的更简单方法为了使生活更轻松，Java 提供了自动将文本转义为
target和的工具更换零件。所以现在我们可以只关注字符串，而忘记正则表达式语法：在我们的例子中，它看起来像
更好：使用
replace如果我们真的不需要正则表达式语法支持，那么就不要涉及
完全替换所有。相反，让我们使用replace。这两种方法都会替换所有目标，但replace不涉及正则表达式语法。所以你可以简单地写TLDR: use
theString = theString.replace("\\", "\\\\");instead.Problem
replaceAll(target, replacement)uses regular expression (regex) syntax fortargetand partially forreplacement.Problem is that
\is special character in regex (it can be used like\dto represents digit) and in String literal (it can be used like"\n"to represent line separator or\"to escape double quote symbol which normally would represent end of string literal).In both these cases to create
\symbol we can escape it (make it literal instead of special character) by placing additional\before it (like we escape"in string literals via\").So to
targetregex representing\symbol will need to hold\\, and string literal representing such text will need to look like"\\\\".So we escaped
\twice:\\"\\\\"(each\is represented as"\\").In case of
replacement\is also special there. It allows us to escape other special character$which via$xnotation, allows us to use portion of data matched by regex and held by capturing group indexed asx, like"012".replaceAll("(\\d)", "$1$1")will match each digit, place it in capturing group 1 and$1$1will replace it with its two copies (it will duplicate it) resulting in"001122".So again, to let
replacementrepresent\literal we need to escape it with additional\which means that:\\\\looks like"\\\\"BUT since we want
replacementto hold two backslashes we will need"\\\\\\\\"(each\represented by one"\\\\").So version with
replaceAllcan look likeEasier way with
replaceAllTo make out life easier Java provides tools to automatically escape text into
targetandreplacementparts. So now we can focus only on strings, and forget about regex syntax:which in our case can look like
Even better: use
replaceIf we don't really need regex syntax support lets not involve
replaceAllat all. Instead lets usereplace. Both methods will replace alltargets, butreplacedoesn't involve regex syntax. So you could simply write为了避免这种麻烦，您可以使用
replace（它采用纯字符串）而不是replaceAll（它采用正则表达式）。您仍然需要转义反斜杠，但不需要以正则表达式所需的方式进行转义。To avoid this sort of trouble, you can use
replace(which takes a plain string) instead ofreplaceAll(which takes a regular expression). You will still need to escape backslashes, but not in the wild ways required with regular expressions.您需要转义第一个参数中的（转义的）反斜杠，因为它是正则表达式。替换（第二个参数 - 请参阅 Matcher#replaceAll(String)) 也有反斜杠的特殊含义，所以你必须将它们替换为：
You'll need to escape the (escaped) backslash in the first argument as it is a regular expression. Replacement (2nd argument - see Matcher#replaceAll(String)) also has it's special meaning of backslashes, so you'll have to replace those to:
是的......当正则表达式编译器看到你给它的模式时，它只看到一个反斜杠（因为Java的词法分析器已经将双反斜杠变成了一个反斜杠）。不管你信不信，你需要将
"\\\\"替换为"\\\\"！ Java 确实需要一个好的原始字符串语法。Yes... by the time the regex compiler sees the pattern you've given it, it sees only a single backslash (since Java's lexer has turned the double backwhack into a single one). You need to replace
"\\\\"with"\\\\", believe it or not! Java really needs a good raw string syntax.