XPath Tutorial - How to select elements in XPATH based on attribute and element value example

In this XPATH tutorial we will see example of selecting elements based
upon its value or attribute value. We will see how to select between two
elements based upon value of its child elements or based upon value of its
attribute. XPATH is an important concept to understand if you are working with
XML files. Most of Back-office platform relies on XML
files for transporting data from one system to other and if you are working
on any back-office or middle office system in Java or .NET, its important to know
about XPATH and be able to use XPATH to select data from XML. Some time back I
have shared my XPATH
notes for Java programmer and this example shows true power of XPATH as how convenient its to made selective decision. For those who are completely new in
XML and XPATH, XPATH is great xml tool which allows you to query XML document
and select or retrieve selective data much like SQL but if you are new to XPATH
or haven't had much experience with XML tool and technology than you will
struggle to find correct syntax of XPATH for your different need.

XPATH to select element based on attribute
and value

Here is our sample xml, which we will use in this XPATH tutorial :

        orderNumber="1">

                Electronics

                100

       

        orderNumber="2">

                Computers

                200

       

        orderNumber="3">

                food

                300

       

In first example of XPATH expression we will see how to select total
element for order which has item value "Electronics"

XPATH :

/orders/order[item/text()='Electronics']/total

value : 100

here text() function returns value of element

[] brackets are used to define condition or
predicate, which is comparing text of tag with “Electronics”.
Similarly we can extend this XPATH to find total for Orders where item is
Computers and food

/orders/order[item/text()='Computers']/total

200

/orders/order[item/text()='food']/total

300

On second example of XPATH expression we will find total element for
order whose orderNumber attribute has value "2"

XPATH : /orders/order[@orderNumber='1']/total

value : 100

here [] is used for condition and @ is used to
get value from attribute.

/orders/order[@orderNumber='2']/total

200

/orders/order[@orderNumber='3']/total

300

If you are new to XML or XPATH I suggest using XML-SPY tool it has in
built XPATH evaluator which shows the result of XPATH as soon as you type and
it supports XPath1.0 and XPATH2.0 as beta. It also has XPATH copy functionality
so you can just select any element in XML in its grid view and copy its XPATH
to use in your Java program.

Other Java and XML tutorials you may like

Difference
between DOM and SAX parser in Java

How
to read XML files using SAX parser in Java

How
to parse XML files using DOM parser in Java

How
to escape XML Meta characters from String in Java program

How
to read and modify XML files using JDOM parser in Java

Source:http://javarevisited.blogspot.com/2012/12/xpath-tutorial-example-how-to-select-elements.html