java - How to retrieve a value from a list of keys/values separated by pipes? -

i have string like:

string s = "a=xxx|b = yyy|c= zzz" 

i trying write function returns value corresponding given key not work expected (it returns empty string):

static string getvaluefromkey(string s, string key) {   return s.replaceall(key + "\\s*=\\s*(.*?)(\\|)?.*", "$1"); } 

test:

static void test() {   string s = "a=xxx|b = yyy|c= zzz";   assertequals(getvaluefromkey(s, "a"), "xxx");   assertequals(getvaluefromkey(s, "b"), "yyy");   assertequals(getvaluefromkey(s, "c"), "zzz"); } 

what regex need pass tests?

using replaceall here seems overkill, because method have iterate on entire string. instead use matcher , find method stop after matching searched regex (in out case key=value pair).

so maybe use like:

static string getvaluefromkey(string s, string key) {     matcher m = pattern.compile(             "(?<=^|\\|)\\s*" + pattern.quote(key) + "\\b\\s*=\\s*(?<value>[^|]*)")             .matcher(s);     if (m.find())         return m.group("value");     else         return null;// or maybe return empty string "" may misleading                      // values empty strings }