java corporate training - xml_jaxb1

7/29/2019 Java Corporate Training - XML_JAXB1

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Siva Reddy

CORE

JAVA


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Class Summary

XML

What is XML

Where to use XML

XML vs HTML

Defining XML XML naming rules

Attributes

DTD

Java Corporate Training - Core Java 2


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XML - JAXB Java Architecture for XML Binding (JAXB) is a Java standard that defines how Java

objects are converted from and to XML.

JAXB defines an API for reading and writing Java objects to and from XML

documents.

We can archive this with JAXP(Java API for XML Parser) with SAX and DOM. With

JAXP programmer have to implement all the logic to create XML or read the XML

and bind the element with objects. JAXB reduces this effort to parse or create XML

with Java objects.

JAXB uses different terminology to read and write the XML.

Marshalling is a technique used to create XML from Java objects.

UnMarshalling is a technique used to read XML and bind these data with

Objects.

JABX is API contains set of classes and interfaces to do marshalling andunmarshalling.


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XML - JAXB

This architecture works in two steps.

In first step create a valid XSD and generate Java class files to

store the XML data. Creating a class files are done by JAXB tool.

Use IDE to do above task. Or you can do it my using XJC tool.

xjc.sh -p -d Note you need to download the JAXB API and tools if your using JDK 1.4

The second step is create objects by using generated classes and

pass it to JAXB API.

XML SchemaJava Classes &

interfaces

JAXB tool

(Binding

compiler)

XML Document

Application

J

avaClasses

JAXB

API

Marshalling

UnMarshalling

Binding


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XML - JAXB

JAXB APIjavax.xml.bind.JAXBElement - Represents an element. XJC tool will genare

ObJectFactory class. Use this class to generate the JAXB element.

JAXBElement poElement = (new ObjectFactory()).create();

javax.xml.bind.JAXBContext This is a base class for JAXB API. While creating an object

we need to pass the Java classes path. Use below syntax.

JAXBContext jaxbContext = JAXBContext.newInstance(");

javax.xml.bind.Marshaller

This class control the process of creating XML.

Marshaller marshaller = jaxbContext.createMarshaller();

To formate the data use below method.

marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, new Boolean(true));

use below method to create XML.

marshaller.marshal(, );

javax.xml.bind.Unmarshaller - This class controls the process of unmarshalling.

Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();

Use below method to map the data into java clases.

unmarshaller.unmarshal();


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XML - JAXB

JAXB AnnotationsBelow are the main annotations used in JAXB API.

@XmlType(propOrder = { "field2", "field1",.. }) - Allows to define the order in which thefields are written in the XML file.

@XmlRootElement(namespace = "namespace") - Define the root element for a XML

tree.

@XmlElement(name = "neuName") - Define the XML element which will be used.

Only need to be used if the neuNeu is different then the JavaBeans Name.


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XML - JAXB

Using Marshalling Create XML schema

Generate Java Classes.

Create Java objects with generated classes and pas the values. Use below code to generate XML.

BankType bank=new BankType();

Bank.setName(MyBank);

JAXBElement poElement = (new ObjectFactory()).createBank(bank);

JAXBContext jaxbContext = JAXBContext.newInstance("org.example.newxmlschema");

Marshaller jaxbMarshaller = jaxbContext.createMarshaller();

jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

jaxbMarshaller.marshal(poElement , System.out);


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XML - JAXB

Using UnMarshalling Create XML schema

Generate Java Classes.

Use below code to read XML.

JAXBContext jaxbContext = JAXBContext.newInstance("org.example.newxmlschema");

Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();

JAXBElement root=(JAXBElement)um.unmarshal(new

File("sample.xml"));

BankType bank=(BankType)root.getValue();


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QUESTIONS?


java corporate training - xml_jaxb1

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