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Using JAXB
Revisited
1
An XSDL Document for an ItemList
<?xml version="1.0" encoding="utf-8"?>
<xsd:schema
xmlns:xsd='http://www.w3.org/2001/XMLSchema'>
<xsd:element name="itemList">
<xsd:complexType>
<xsd:sequence>
<xsd:element ref="item"
minOccurs="0" maxOccurs="3"/>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
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<xsd:element name="item">
<xsd:complexType>
<xsd:sequence>
<xsd:element ref="name"/>
<xsd:element ref="quantity"/>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
<xsd:element name="name" type="xsd:string"/>
<xsd:element name="quantity" type="xsd:short"/>
</xsd:schema>
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A Document Instance
<?xml version="1.0" encoding="utf-8"?>
<itemList
xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
xsi:noNamespaceSchemaLocation="itemList.xsd">
<item>
<name>pen</name>
<quantity>5</quantity>
</item>
<item>
<name>eraser</name>
<quantity>7</quantity>
</item>
<item>
<name>stapler</name>
<quantity>2</quantity>
</item>
</itemList>
4
An Ant Build file
<?xml version="1.0"?>
<!– adapted from Sun’s jaxb build file 
<project basedir="." default="run">
<path id="classpath">
<fileset dir="D:\jwsdp-1.2\jaxb\lib" includes="*.jar"/>
<fileset dir="D:\jwsdp-1.2\common\lib" includes="*.jar"/>
<fileset dir="D:\jwsdp-1.2\jaxp\lib\endorsed" includes="*.jar"/>
<fileset dir="D:\jwsdp-1.2\jwsdp-shared\lib" includes="*.jar"/>
<fileset dir="D:\jwsdp-1.2\jaxp\lib" includes="*.jar"/>
<pathelement location="."/>
</path>
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<taskdef name="xjc" classname="com.sun.tools.xjc.XJCTask">
<classpath refid="classpath" />
</taskdef>
<!-- generate Java source files -->
<target name="generate">
<!-- generate the Java content classes from the schema -->
<echo message="Compiling the schema..."/>
<xjc schema="itemList.xsd" target="." package="itemListAPI"/>
<!-- generate the javadocs from the content classes -->
<mkdir dir="docs/api"/>
<javadoc packagenames="itemListAPI"
sourcepath="."
destdir="docs/api"
windowtitle="Generated Interfaces for itemList.xsd">
<classpath refid="classpath" />
</javadoc>
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<!-- compile all of the java sources -->
<echo message="Compiling the java source files..."/>
<javac srcdir="." destdir="." debug="on">
<classpath refid="classpath" />
</javac>
</target>
<target name="JustJava">
<!-- compile all of the java sources -->
<echo message="Compiling the java source files..."/>
<javac srcdir="." destdir="." debug="on">
<classpath refid="classpath" />
</javac>
</target>
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<target name="JustJavaRun">
<echo message="java runtime"/>
<java classname="Main" fork="true">
<classpath refid="classpath" />
</java>
</target>
<target name="run" depends="generate">
<echo message="Running the sample application..."/>
<java classname="Main" fork="true">
<classpath refid="classpath" />
</java>
</target>
</project>
8
Running the build
D:\McCarthy\www\95-733\examples\struts1\src\VO>ant generate
Buildfile: build.xml
generate:
[echo] Compiling the schema...
[xjc] Compiling file:/D:/McCarthy/www/95-733/examples/struts1/src/VO/itemL
ist.xsd
[xjc] Writing output to D:\McCarthy\www\95-733\examples\struts1\src\VO
[javadoc] Generating Javadoc
[javadoc] Javadoc execution
[javadoc] Loading source files for package itemListAPI...
[javadoc] Constructing Javadoc information...
[javadoc] Standard Doclet version 1.4.2
[javadoc] Building tree for all the packages and classes...
[javadoc] Building index for all the packages and classes...
[javadoc] Building index for all classes...
[echo] Compiling the java source files...
[javac] Compiling 42 source files to D:\McCarthy\www\95-733\examples\struts1
\src\VO
BUILD SUCCESSFUL
9
Viewing the docs
10
Write the client
import java.io.File;
import java.io.IOException;
import java.math.BigDecimal;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.UnmarshalException;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.ValidationEvent;
import javax.xml.bind.util.ValidationEventCollector;
// import java content classes generated by binding compiler
import itemListAPI.*;
public class Main {
// This sample application demonstrates how to enable validation during
// the unmarshal operations.
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public static void main( String[] args ) {
try {
// create a JAXBContext capable of handling classes generated into
// the itemListAPI package
JAXBContext jc = JAXBContext.newInstance( "itemListAPI" );
// create an Unmarshaller
Unmarshaller u = jc.createUnmarshaller();
// enable validation
u.setValidating( true );
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// in this example, we will allow the Unmarshaller's default
// ValidationEventHandler to receive notification of warnings
// and errors which will be sent to System.out. The default
// ValidationEventHandler will cause the unmarshal operation
// to fail with an UnmarshalException after encountering the
// first error or fatal error.
// unmarshal an invalid itemList instance document into a tree of Java
// content objects composed of classes from the itemListAPI package.
ItemList itemList =
(ItemList)u.unmarshal( new File( "itemList.xml" ) );
java.util.List list = itemList.getItem();
System.out.println("The length of the list is " + list.size());
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int n = list.size();
for(int k = 0; k < n; k++) {
ItemType it = (ItemType)list.get(k);
String st = it.getName();
System.out.println(st);
}
} catch( UnmarshalException ue ) {
// The JAXB specification does not mandate how the JAXB provider
// must behave when attempting to unmarshal invalid XML data. In
// those cases, the JAXB provider is allowed to terminate the
// call to unmarshal with an UnmarshalException.
System.out.println( "Caught UnmarshalException" );
} catch( JAXBException je ) {
je.printStackTrace();
}
}
}
14
Running the Client
D:\McCarthy\www\95-733\examples\struts1\src\VO>ant JustJavaRun
Buildfile: build.xml
JustJavaRun:
[echo] java runtime
[java] The length of the list is 3
[java] pen
[java] eraser
[java] stapler
BUILD SUCCESSFUL
Total time: 2 seconds
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