Script painless use regex match not found

[wnn (weining)]

i want find a word from my filed.i use the filed.keyword .but match not found
def m=/.*[0-9]+/.matcher("2020年11月");
i want get a result = 202011，but the true result is not match；
so，my friend，please help me；thank you very much

this is all my script

def dateStr=doc['date.keyword'].value;
 if(dateStr!=null&&dateStr!=''){
def m=/.*[0-9]+/.matcher(dateStr); 
 if(m.matches()){
return Integer.parseInt(m.group());
}else{
return 0;
} } 

[wnn (weining)]

i reslove this question;
matches is match all;
so should use find
for example：

def dateStr=doc['date.keyword'].value;
 if(dateStr!=null&&dateStr!=''){
def m=/.*[0-9]+/.matcher(dateStr); 
 if(m.find()){
return Integer.parseInt(m.group());
}else{
return 0;
} }