Java正则表达式将带引号的字符串与嵌入式转义的引号匹配

Question

I need help with a regex for matching a quoted string that could have an embedded escaped quote.

For example, given string "'John\\'s bike'" . The basic pattern i was starting with, "'[^']*'" , and expanding it to negate case of embedded escaped quotes using lookbehind doesn't work: "'((?<\\\\)[^'])*'" .

Anyone has idea?

The string could be a series of quoted strings, eg, "'John\\'s bike', 'Mary\\'s hat', 'my shoes'", and i want to tokenize each of the quoted substrings separately.

Answer 1

You can accept any character between quotes which is

• preceded by \\
• not ' .

So your regex can look like:

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

which in Java should look like "'(\\\\\\\\.|[^'])*'" (to create \\ literal in regex we need to escape it like \\\\ but same rules applies in String literals so we need to escape these two \\ again which finally gives us "\\\\\\\\" )

Demo based on your example:

String input = "'John\\'s bike', 'Mary\\'s hat', 'my shoes'";
Pattern p = Pattern.compile("'(\\\\.|[^'])*'");
Matcher m = p.matcher(input);
while(m.find()){
    System.out.println(m.group());
}

Output:

'John\'s bike'
'Mary\'s hat'
'my shoes'