正则表达式以匹配JSON编码的字符串

Question

Hi I've been trying to create a Regex in Java to match JSON data that I have converted to a string using json_encode. I've been reading through examples on stackoverflow but I'm not sure do they just relate to pure JSON or strings containing JSON representation. I've tried applying a few but can't get them to work.

Looking here:

Regex to validate JSON

And here:

Regex to match a JSON String

This is the string I am trying to use my Regex to match to:

[{"resourceUri":"file:\/home\/admin\/test-modeling\/apache-tomcat-7.0.70\/temp\/IOS\/filetest-file-files.txt#\/\/@statements.12\/@typeList.0\/@enumLiterals.11","severity":"WARNING","lineNumber":333,"column":9,"offset":7780,"length":24,"message":"Enum name should be less than 20 characters"}]

I've tried using this answer and it matches fine when I use regex101 for testing.

https://stackoverflow.com/a/6249375/5476612

I'm using this regex from here:

/\A("([^"\\]*|\\["\\bfnrt\/]|\\u[0-9a-f]{4})*"|-?(?=[1-9]|0(?!\d))\d+(\.\d+)?([eE][+-]?\d+)?|true|false|null|\[(?:(?1)(?:,(?1))*)?\s*\]|\{(?:\s*"([^"\\]*|\\["\\bfnrt\/]|\\u[0-9a-f]{4})*"\s*:(?1)(?:,\s*"([^"\\]*|\\["\\bfnrt\/]|\\u[0-9a-f]{4})*"\s*:(?1))*)?\s*\})\Z/is

However when I try and use it as a string in Java I get escaped character issues.

Can anyone help me with fixing the regex to work as a String to use in Java or help me create one that will work?

EDIT 1: Here's the full String I am looking at that I am trying to match the JSON string above against:

../../tool/model/toolingValidationReport.php?fileName=test-testing-types.txt&fileSize=18380&validationReport=[{"resourceUri":"file:\/home\/admin\/test-modeling\/apache-tomcat-7.0.70\/temp\/IOS\/filetest-file-files.txt#\/\/@statements.12\/@typeList.0\/@enumLiterals.11","severity":"WARNING","lineNumber":333,"column":9,"offset":7780,"length":24,"message":"Enum name should be less than 20 characters"}] target=

EDIT 2: Here's the Java I am using to perform the regex check. The href variable contains the String content shown in edit 1.

Pattern validationReportPattern = Pattern.compile(getValidationReportPattern());
Matcher validationReportMatcher = validationReportPattern.matcher(href);

public String getYangValidationReportPattern(){
   return "(\\[\\{.*\\}])"; 
}

String validationReport  = validationReportMatcher.group(1);

Answer 1

The regex pattern must be "(\\\\[\\\\{.*}])" in Java but the real problem is that no match has been attempted. You have to call find() before calling group() .

If you do that it works, see here online at ideone .

Output:

Match: [{"resourceUri":"file:\/home\/admin\/test-modeling\/apache-tomcat-7.0.70\/temp\/IOS\/filetest-file-files.txt#\/\/@statements.12\/@typeList.0\/@enumLiterals.11","severity":"WARNING","lineNumber":333,"column":9,"offset":7780,"length":24,"message":"Enum name should be less than 20 characters"}]

The find() method returns a boolean so that you can check if there is an occurrence. If you would not check that with find() first you would get an java.lang.IllegalStateException: No match found exception.

if (validationReportMatcher.find())
{
   String validationReport  = validationReportMatcher.group(1);
   System.out.println ("Match: " + validationReport);
}
else
{
   System.out.println ("No match");
}

If you have to search for multiple matches you call find() in a while loop:

while (validationReportMatcher.find())
{
   String validationReport  = validationReportMatcher.group(1);
   System.out.println ("Match: " + validationReport);
}

But this seems not to be neccessary as you just look for one occurrence.