Split String in Java with potential split characters used in String parts

Question

How would you split this String format into parts:

message_type={any_text}&message_number={digits}&code={digits}&id={digits}&message={any_text}&timestamp={digits_with_decimal}

Where in the message={any_text} part, the {any_text} may contain a & and a = thus not being able to do String split by & or =

And the order of the message parts may be scrambled or not in this order. I am thinking that a pattern can be extracted for a solution, ={the_text_needed}& however this would not apply for the last part of the String as there will be no & at the end.

Is this any different than [this](http://stackoverflow.com/questions/29051752/regex-to-parse-a-command-string)? — Sotirios Delimanolis, Mar 15 '15 at 05:09
Yes I think, because that question was intended for Regex solution, this one is not just for regex — quarks, Mar 15 '15 at 05:11
the "{}" is just my representation of the pattern needed to be done not really part of the message String — quarks, Mar 15 '15 at 05:18
I think what I need to do is, do a indexof("message_type") then traverse the String char by char then check for a pattern e.g. &message_number= or EOL — quarks, Mar 15 '15 at 05:20
so.. you have data like.. `message=qwqf&po=qqw&mesage_number=9887...` ? i mean without any braces? — karthik manchala, Mar 15 '15 at 05:21
More like: message_type=test&message=something+is+wrong+&+=+here&code=123 — quarks, Mar 15 '15 at 05:23
Looks like you are trying to parse get parameters of a HTTP URL? Servers and libraries already do that. Why are you trying to reinvent the wheel? — RaviH, Mar 15 '15 at 05:27
are you constructing this string or just capturing and parsing? (could be irrelevent.. but curious) — karthik manchala, Mar 15 '15 at 05:29
@karthikmanchala Just capturing it from a web service we paid for. Actually I myself find the response so wrong and hard to parse. :-( — quarks, Mar 15 '15 at 05:40
is there any particular format of the string that we can take advantage of? like.. order of `message_type`, `code`, `id`, `message` always be in same order in the string? — karthik manchala, Mar 15 '15 at 05:43
@karthikmanchala the problem is the order is not always like that — quarks, Mar 15 '15 at 05:57
Late to the party: does this help: https://regex101.com/r/iE0hU3/1 — Khanna111, Mar 15 '15 at 07:02

Kartic · Accepted Answer · 2015-03-15T11:56:09.970

I hope this will work -

String originalString = "message_type={a&=b}&message_number={1}&code={2}&id={3}&message={a&=b}&timestamp={12}";
Map<String, String> resultMap = new HashMap<String, String>();
String[] splitted1 = originalString.split("&+(?![^{]*})");
for (String str : splitted1) {
    String[] splitted2 = str.split("=+(?![^{]*})");
    resultMap.put(splitted2[0], splitted2[1]);
    splitted2 = null;
}

If parameter values are not enclosed within curly braces, then its really tough. I can think of a solution, but I don't know whether it could break in some situation or not -

String originalString = "message_type=msgTyp&message_number=1&code=2&message=a&=b&timestamp=12";
String[] predefinedParameters = {"message_type", "message_number", "code", "message", "timestamp"};
String delimeter = "###";

for (String str : predefinedParameters) {
    originalString = originalString.replace(str+"=", delimeter+str+"=");
}

originalString = originalString.substring(delimeter.length());

String[] result = originalString.split("&"+delimeter);

Yes, there are no curly braces – quarks Mar 16 '15 at 05:08 — quarks, Mar 16 '15 at 05:08

score 0 · Answer 2 · answered Mar 15 '15 at 06:01

Assuming that none of the fields contain & or =, you could:

String[] fields = message.split("&");
Map<String,String> fieldMap = new LinkedHashMap<>();
for (String field:fields)
{
    String[] fieldParts = field.split("=");
    fieldMap.put(fieldParts[0],fieldParts[1]);
}

and have a map of all your fields.

score 0 · Answer 3 · edited May 23 '17 at 11:45

0

That you are trying to do is to parse a querystring , you should check:

Query String Manipulation in Java

edited May 23 '17 at 11:45

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answered Mar 15 '15 at 06:46

Ricardo Umpierrez

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Split String in Java with potential split characters used in String parts

3 Answers3