CODEWITHSUNDEEP
javaregexstring
code_fish
code_fish

Reputation: 3436

Java String tokens

I have a string line

String user_name = "id=123 user=aron name=aron app=application";

and I have a list that contains: {user,cuser,suser}

And i have to get the user part from string. So i have code like this

List<String> userName = Config.getConfig().getList(Configuration.ATT_CEF_USER_NAME);
String result = null;

for (String param: user_name .split("\\s", 0)){
for(String user: userName ){
    String userParam = user.concat("=.*");
    if (param.matches(userParam )) {
        result = param.split("=")[1];
    }
}   
}

But the problem is that if the String contains spaces in the user_name, It do not work. For ex: 

String user_name = "id=123 user=aron nicols name=aron app=application";

Here user has a value aron nicols which contain spaces. How can I write a code that can get me exact user value i.e. aron nicols

Upvotes: 0

Views: 140

Answers (3)

Pshemo
Pshemo

Reputation: 124215

If you want to split only on spaces that are right before tokens which have = righ after it such as user=... then maybe add look ahead condition like

split("\\s(?=\\S*=)")

This regex will split on

  • \\s space
  • (?=\\S*=) which has zero or more * non-space \\S characters which ends with = after it. Also look-ahead (?=...) is zero-length match which means part matched by it will not be included in in result so split will not split on it.

Demo:

String user_name = "id=123 user=aron nicols name=aron app=application";
for (String s : user_name.split("\\s(?=\\S*=)"))
    System.out.println(s);

output:

id=123
user=aron nicols
name=aron
app=application

From your comment in other answer it seems that = which are escaped with \ shouldn't be treated as separator between key=value but as part of value. In that case you can just add negative-look-behind mechanism to see if before = is no \, so (?<!\\\\) right before will require = to not have \ before it.
BTW to create regex which will match \ we need to write it as \\ but in Java we also need to escape each of \ to create \ literal in String that is why we ended up with \\\\.

So you can use 

split("\\s(?=\\S*(?<!\\\\)=)")

Demo:

String user_name = "user=Dist\\=Name1, xyz src=activedirectorydomain ip=10.1.77.24";
for (String s : user_name.split("\\s(?=\\S*(?<!\\\\)=)"))
    System.out.println(s);

output:

user=Dist\=Name1, xyz
src=activedirectorydomain
ip=10.1.77.24

Upvotes: 5

anubhava
anubhava

Reputation: 784898

Do it like this:

First split input string using this regex:

" +(?=\\w+(?<!\\\\)=)"

This will give you 4 name=value tokens like this:

id=123
user=aron nicols
name=aron
app=application

Now you can just split on = to get your name and value parts.

Regex Demo

Regex Demo with escaped =

Upvotes: 4

zx81
zx81

Reputation: 41838

CODE FISH, this simple regex captures the user in Group 1: user=\\s*(.*?)\s+name=

It will capture "Aron", "Aron Nichols", "Aron Nichols The Benevolent", and so on. It relies on the knowledge that name= always follows user=

However, if you're not sure that the token following user is name, you can use this:

user=\s*(.*?)(?=$|\s+\w+=)

Here is how to use the second expression (for the first, just change the string in Pattern.compile:

String ResultString = null;
try {
    Pattern regex = Pattern.compile("user=\\s*(.*?)(?=$|\\s+\\w+=)", Pattern.CASE_INSENSITIVE | Pattern.UNICODE_CASE);
    Matcher regexMatcher = regex.matcher(subjectString);
    if (regexMatcher.find()) {
        ResultString = regexMatcher.group(1);
    } 
} catch (PatternSyntaxException ex) {
    // Syntax error in the regular expression
}

Upvotes: 1

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