How to capture certain text within a StringBuffer Java

Question

I have a StringBuffer object with the following contents:

<ET>read input: 1.629ms</ET>
<ET>There were 3 errors:
<Error>
    <ErrorId>AllConditionsTrue</ErrorId>
    <MetaData>
        <Entry>
            <Key>Balance Due</Key>
            <Value>1500.99</Value>
        </Entry>
    </MetaData>
</Error>

<Error>
    <ErrorId>Opposite</ErrorId>
    <MetaData>
        <Entry>
            <Key>Node</Key>
        </Entry>
    </MetaData>
</Error>

<Error>
    <ErrorId>minInclusive</ErrorId>
    <MetaData>
        <Entry>
            <Key>Description</Key>
            <Value>Wages Amount</Value>
        </Entry>
    </MetaData>
</Error>

: 0.027ms</ET>
<ET>convert: 319.414ms</ET>
<FORM id="123"/>
<DATA size="11920"/>
<ERROR code="0"/>

How can I capture just the text which is at and within the Error Tags (<Error> some text </Error> ). So my new String or StringBuffer object contains:

<Error>
    <ErrorId>AllConditionsTrue</ErrorId>
    <MetaData>
        <Entry>
            <Key>Balance Due</Key>
            <Value>1500.99</Value>
        </Entry>
    </MetaData>
</Error>

<Error>
    <ErrorId>Opposite</ErrorId>
    <MetaData>
        <Entry>
            <Key>Node</Key>
        </Entry>
    </MetaData>
</Error>

<Error>
    <ErrorId>minInclusive</ErrorId>
    <MetaData>
        <Entry>
            <Key>Description</Key>
            <Value>Wages Amount</Value>
        </Entry>
    </MetaData>
</Error>

How can I accomplish my goal using Java?

Edit

Trying both your guys solutions:

Pattern p = Pattern.compile("<Error>.*?<\\/Error>", Pattern.DOTALL);
Matcher m = p.matcher(buf.toString());

String errorText = "";

while (m.find()) {
    errorText = m.group(1);
}

I seem to only get 3 error tag element not all 3.

Example:

<Error>
    <ErrorId>minInclusive</ErrorId>
    <MetaData>
        <Entry>
            <Key>Description</Key>
            <Value>Wages Amount</Value>
        </Entry>
    </MetaData>
</Error>

Please don't use StringBuffer as it was replaced with StringBuilder more than ten years ago. — Peter Lawrey, Mar 15 '16 at 07:59

score 1 · Answer 1 · answered Mar 15 '16 at 07:30

1

Regex:

<Error>.*?<\/Error>

Demo

answered Mar 15 '16 at 07:30

Tim007

2,557
1
11
20

Thanks but this regex only seems to grab one Error tag element, see my edit to the original post – arabian_albert Mar 15 '16 at 07:45
1

@arabian_albert check this http://stackoverflow.com/questions/16517689/confused-about-matcher-group-in-java-regex – Tim007 Mar 15 '16 at 07:59
Thanks @Tim007 I definitely need to readup on regex – arabian_albert Mar 15 '16 at 08:05

score 1 · Answer 2 · answered Mar 15 '16 at 08:08

1

SaxParse would be a better solution than string parser.

It will be portable for your future references as well.

Refer this sax documentation :

http://docs.oracle.com/javase/7/docs/api/javax/xml/parsers/SAXParser.html

answered Mar 15 '16 at 08:08

Parth Joshi

452
4
6

Nikolas Charalambidis · Accepted Answer · 2016-03-15T07:50:11.927

0

Note that your string contains new lines, so you have to use \n. Try this out:

<Error>((?:.*?\n?)+.*?)<\/Error>

Check the Regex101

edited Mar 15 '16 at 07:50

answered Mar 15 '16 at 07:38

Nikolas Charalambidis

40,893
16
117
183

Trying your solution now – arabian_albert Mar 15 '16 at 07:45
Thanks, your solution works for this particular problem. Now will this work for any number of Error tags? – arabian_albert Mar 15 '16 at 07:47
Updated. Try it out :) – Nikolas Charalambidis Mar 15 '16 at 07:50
It didn't seem to work, I now only get 1 error Tag :( – arabian_albert Mar 15 '16 at 07:54
This is what I tried (escaping the closing error tag) `Pattern p = Pattern.compile("((?:.*?\n?)+.*?)<\\/Error>", Pattern.DOTALL);` – arabian_albert Mar 15 '16 at 07:55
1

You have forgotten to double \\ at new line character \\n. You have only single one \n. – Nikolas Charalambidis Mar 15 '16 at 07:59
Whoops, I'm terrible at regex. Would something like this `"((?:.*?\\n?)+.*?)<\\/Error>"` do? Because this still gives only 1 error tag – arabian_albert Mar 15 '16 at 08:04
1

@arabian_albert `while (m.find()) { System.out.println(m.group(1)); }` It may print all 3. `errorText = m.group(1);` you will only get the last one, other is overwrite because in loop, check this http://stackoverflow.com/questions/6417435/find-the-last-match-with-java-regex-matcher – Tim007 Mar 15 '16 at 08:13
@Tim007 got it! Thanks for the linked post – arabian_albert Mar 15 '16 at 08:24

How to capture certain text within a StringBuffer Java

3 Answers3