string.replaceAll Java不适用于环视正则表达式吗？

Question

I have a json string like this:

string = "{name={first=sam, last=vo}, hobbies={hobby1=football, hobby2=swimming}}"

And I want to remove the "name=" and the "hobbies=", so that I use this pattern: \\w*\\=(?={) ->tested using editPadPro

However, when I use the replace all in java:

String pattern = "\\w*\\=(?={)";
String removedParent = string.replaceAll(pattern, "");

I got this error message

"Exception in thread "main" java.util.regex.PatternSyntaxException: Illegal repetition near index 7
\w*\=(?={)"

Can you please give me some advices to get this work?

Regards,

Sam

Answer 1

The problem is that the { character is a special character in regex syntax which denotes an amount (for instance \\d{2} denotes 2 digits). In your case, you want to match the literal { , meaning that you need to escape the { character, so you need to change your regex to this: "\\\\w*\\\\=(?=\\\\{)"; .

For me, this yielded:

{{first=sam, last=vo}, {hobby1=football, hobby2=swimming}}

Answer 2

java.util.regex.PatternSyntaxException: Illegal repetition

comes because of your "{" in "\\\\w*\\\\=(?={)" . "{" and "}" are special characters to state characters repetitions as you might know ...

just try to escape it like that "\\\\w*\\\\=(?=\\\\{)" . and since you're working with json , please consider using a JSON-Parser like:

• Jackson
• net.json