匹配未在JAVA中转义的引号的正则表达式

Question

I am trying to create a regex in JAVA that would match a string like: 'test " abcd \\" ef" test' Let's say that I would want to know if between the quotes I have the characters abcdef in this order and any other character between them (but since I'm interested only in the substring between the quotes, the character between them can't be a quote, except the case in which the quote is escaped) Is it possible to do this?

I managed to create this regex

("[^\"]*\"[^\"]*a[^\"]*b[^\"]*c[^\"]*d[^\"]*e[^\"]*f[^\"]*\"[^\"]*")

that works for any case except the ones with escaped quotes embedded in the string.

Answer 1

You're almost there... add the case for the quoted quote, which can be matched with

\\\"

so each of your [^\\"]* cases (except the first and last, I guess) should become

([^\"]|\\\")*

... but you also need to take care of backslashes (because, for example, in

"foo\\"

the final quote is a "real" (non-escaped) quote, even though there's a backslash before it.) So in fact you need the [^\\"]* cases to become:

([^\"\\]|\\.)*

or in other words: match anything that's not \\ or " , or is \\ followed by a character that's ignored.

NB This will mean that, for example, in the string "xxx\\abcdef" the "\\a" will not be matched as an "a" , but that's probably what you want (since "\\a" typically denotes the ASCII "BEL" control character).