String Operation to get particular value inside the string using java

Question

I have a string as below.

<employees>
<emp>
<name>yaakobu</name>
<sal>$20000</sal>
<designation>Manager</designation>
</emp>

<emp>
<name>daaniyelu</name>
<sal>$2000</sal>
<designation>Operator</designation>
</emp>

<emp>
<name>paadam</name>
<sal>$7000</sal>
<designation>Engineer</designation>
</emp>
</employees>

The above xml i am getting as a string.i was asked not to use parsing due to performance issue.I need to get the second employee 's salary($2000) using java's string operation.Please provide me some pointers.

Your help appreciated.

AFAIK using xml parser will not degrade performance. Notify me if I am wrong. — Harry Joy
– Harry Joy, Commented Jul 2, 2011 at 7:10
"not to use parsing due to performance issue" what non-sense! — Bart Kiers
– Bart Kiers, Commented Jul 2, 2011 at 7:11
Are you finding the XML node by the employee's name or position in the input? — Bohemian
– Bohemian ♦, Commented Sep 1, 2016 at 12:20

Petar Ivanov · Accepted Answer · 2011-07-02 07:11:42Z

2

Your string is xml. Although it might be tempting to use regex or other string manipulation to extract data from xml - don't do it - it's a bad practice.

You should use some XML parser instead.

answered Jul 2, 2011 at 7:11

Petar Ivanov

93.4k11 gold badges84 silver badges95 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Bart Kiers · Accepted Answer · 2011-07-02 07:27:30Z

After you've done this using your string operations, give the following a try:

import org.w3c.dom.*;
import javax.xml.parsers.*;
import javax.xml.xpath.*;

public class Main {
  public static void main(String[] args) throws Exception {
    DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
    domFactory.setNamespaceAware(true);
    DocumentBuilder builder = domFactory.newDocumentBuilder();
    Document doc = builder.parse("test.xml");
    XPath xpath = XPathFactory.newInstance().newXPath();

    // get the salary from the employee at index 1
    XPathExpression expr = xpath.compile("//emp[1]/sal"); 
    Object salary = expr.evaluate(doc, XPathConstants.STRING);
    System.out.println(salary);
  }
}

which should output:

$20000

I'm not guaranteeing it will be faster, but it won't differ all that much I think. And doing it like this will be far less fragile than doing this with indexOf(...) and substring(...) calls.

Petar Minchev · Accepted Answer · 2011-07-02 07:13:32Z

0

I doubt there will be performance issues using an xml parser, but if you want to do it by string parsing, use str.indexOf("<sal>", str.indexOf("<sal>") + 5); Then it will be easy.

answered Jul 2, 2011 at 7:13

Petar Minchev

47.5k12 gold badges107 silver badges120 bronze badges

1 Comment

Petar Minchev Over a year ago

@Bart Kiers - You are correct, my post is just a start for the OP.

subodh · Accepted Answer · 2011-07-02 07:24:57Z

Use xml parser or JAXB api for unmarshal the String into object, you can do it through this way also.

private static Object getObject(String yourXml) throws Exception {



    JAXBContext jcUnmarshal = null;

    Unmarshaller unmarshal = null;

    javax.xml.stream.XMLStreamReader rdr = null;



    //Object obj = null;

    try {



        jcUnmarshal = JAXBContext.newInstance("com.test.dto");

        unmarshal = jcUnmarshal.createUnmarshaller();

        rdr = javax.xml.stream.XMLInputFactory.newInstance().createXMLStreamReader(new StringReader(yourXml));



        //obj = (Object) unmarshal.unmarshal(rdr);

        return (Object) unmarshal.unmarshal(rdr);



    } catch (JAXBException jaxbException) {

        jaxbException.printStackTrace();

        log.error(jaxbException);

        throw new ServiceException(jaxbException.getMessage());

    }

    finally{

        jcUnmarshal = null;

        unmarshal = null;

        rdr.close();

        rdr = null;

    }



    //return obj;



}

facundofarias · Accepted Answer · 2016-09-01 12:01:12Z

0

you might use xstream http://x-stream.github.io/ you put your xml in an object structure and get it from there.

check the samples ,is very easy to use

This if you don't want to parse yourself...:)

edited Sep 1, 2016 at 12:01

facundofarias

3,04933 silver badges27 bronze badges

answered Jul 2, 2011 at 7:15

Cris

5,0176 gold badges50 silver badges76 bronze badges

Collectives™ on Stack Overflow

String Operation to get particular value inside the string using java

5 Answers 5

Comments

Comments

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

Comments

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related