Parsing HTTP XML Response Using Regex In Java

Question

I am making an API call and now I need to get a specific piece of data from the response. I am needing to get the DocumentID for the "Description" Invoice, which in the case below is 110107.

I have already created a method to get data from get a single tag by doing this:

public synchronized String getTagFromHTTPResponseAsString(String tag, String body) throws IOException {

    final Pattern pattern = Pattern.compile("<"+tag+">(.+?)</"+tag+">");
    final Matcher matcher = pattern.matcher(body);
    matcher.find();

    return matcher.group(1);

} // end getTagFromHTTPResponseAsString

However, my problem is with this result set, there are multiple fields with the same tag and I need a specific one. Here is the response:

<?xml version="1.0" encoding="utf-8"?>
<Order TrackingID="351535" TrackingNumber="TEST-843245" xmlns="">
  <ErrorMessage />
  <StatusDocuments>
    <StatusDocument NUM="1">
      <DocumentDate>7/14/2017 6:52:00 AM</DocumentDate>
      <FileName>4215.pdf</FileName>
      <Type>Sales Contract</Type>
      <Description>Uploaded Document</Description>
      <DocumentID>110098</DocumentID>
      <DocumentPlaceHolder />
    </StatusDocument>
    <StatusDocument NUM="2">
      <DocumentDate>7/14/2017 6:52:00 AM</DocumentDate>
      <FileName>Apex_Shortcuts.pdf</FileName>
      <Type>Other</Type>
      <Description>Uploaded Document</Description>
      <DocumentID>110100</DocumentID>
      <DocumentPlaceHolder />
    </StatusDocument>
    <StatusDocument NUM="3">
      <DocumentDate>7/14/2017 6:52:00 AM</DocumentDate>
      <FileName>CRAddend.pdf</FileName>
      <Type>Other</Type>
      <Description>Uploaded Document</Description>
      <DocumentID>110104</DocumentID>
      <DocumentPlaceHolder />
    </StatusDocument>
    <StatusDocument NUM="4">
      <DocumentDate>7/14/2017 6:52:00 AM</DocumentDate>
      <FileName>test.pdf</FileName>
      <Type>Other</Type>
      <Description>Uploaded Document</Description>
      <DocumentID>110102</DocumentID>
      <DocumentPlaceHolder />
    </StatusDocument>
    <StatusDocument NUM="5">
      <DocumentDate>7/14/2017 6:55:00 AM</DocumentDate>
      <FileName>Invoice.pdf</FileName>
      <Type>Invoice</Type>
      <Description>Invoice</Description>
      <DocumentID>110107</DocumentID>
      <DocumentPlaceHolder />
    </StatusDocument>
  </StatusDocuments>
</Order>

I tried creating and testing out my regular expression on https://regex101.com/ and got this RegEx to work there, but I cannot get it to translate over correctly into my Java code:

<Description>Invoice<\/Description>
      <DocumentID>(.*?)<\/DocumentID>

Regex is for String matching, not for XML parsing. I would recommend using one of the many xml parsing libraries. Additionally in my experience Regex can be awkward to use and maintain. — MartinByers
– MartinByers, Commented Jul 14, 2017 at 12:39

Eritrean · Accepted Answer · 2017-07-14 12:55:06Z

1

Try it with Jsoup

Example:

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

public class sssaa {
    public static void main(String[] args) throws Exception {
        String xml = "yourXML";        
        Document doc = Jsoup.parse(xml);
        Elements StatusDocuments = doc.select("StatusDocument");
        for(Element e : StatusDocuments){
            if(e.select("Description").text().equals("Invoice")){
                System.out.println(e.select("DocumentID").text());
            }           
        }
    }
}

answered Jul 14, 2017 at 12:55

Eritrean

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Comments

Dustin N. · Accepted Answer · 2017-07-14 13:15:03Z

0

What I have done to solve this is use StringBuilder to convert the response into a single string and then used this piece of code to get the DocumentID:

// Create the pattern and matcher
Pattern p = Pattern.compile("<Description>Invoice<\\/Description><DocumentID>(.*)<\\/DocumentID>");
Matcher m = p.matcher(responseText);

// if an occurrence if a pattern was found in a given string...
if (m.find()) {
    // ...then you can use group() methods.
    System.out.println("group0 = " + m.group(0)); // whole matched expression
    System.out.println("group1 = " + m.group(1)); // first expression from round brackets (Testing)
}

// Set the documentID for the Invoice 
documentID = m.group(1);

Looks like this is probably not the best way to go about doing this, but it is working for now. I will come back and try to clean this up with a more correct solution from suggestions given here.

answered Jul 14, 2017 at 13:15

Dustin N.

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1 Comment

Dustin N. Over a year ago

@Eritrean answer works great and is much cleaner. I'm implementing that solution

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