Extending DefaultHandler

[David Rancour]

Hi all,

I am writing a very basic example of using the SAX api and am running into
trouble. The class below compiles just fine, but when I try to execute the
code I get a crazy error. Here is the code and the error:

import org.xml.sax.*;
import org.xml.sax.helpers.*;
import java.io.*;

public class xmlEcho extends DefaultHandler
{
public void startDocument() throws SAXException
{
System.out.println("SAX Event: START Document");
}

public void endDocument() throws SAXException
{
System.out.println("SAX Event: END Document");
}

public void startElement(String namespaceURI,String localName, String qName,
Attributes attrs) throws SAXException
{
System.out.println("SAX Event: START Element["
+localName+"]");
for (int i=0;i < attrs.getLength() ;i++ )
{
System.out.println(" ATTRIBUTE "+
attrs.getLocalName(i)+" VALUE "+
attrs.getValue(i));
}
}

public void endElement(String namespaceURI,String localName,
String qName) throws SAXException
{
System.out.println("SAX Event: END Element["
+localName+"]");
}

public void characters(char ch[],int start, int length) throws SAXException
{
System.out.print("SAX Event: CHARACTERS[");
try
{
OutputStreamWriter outw = new OutputStreamWriter(System.out);
outw.write(ch,start,length);
outw.flush();
} catch (Exception e)
{
e.printStackTrace();
}

System.out.println("]");
}

public static void main(String args[])
{
System.out.println("Example1 SAX Events");
try
{
XMLReader xr = XMLReaderFactory.createXMLReader();
xr.setContentHandler(new xmlEcho());
xr.parse(new InputSource(new FileReader("c:\\web.xml")));
}
catch (Exception e)
{
e.printStackTrace();
}
}
}

*********ERROR Text
Exception in thread "main" java.lang.NoClassDefFoundError: org/xml/sax/helpers/DefaultHandler
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$100(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)

How could the program be extending the DefaultHandler class, compile perfectly
then have a problem locating the class?

Any idea's about what I'm doing wrong here? Thanks alot, I am really stuck.

David Rancour

[Rajkamal Gopinath]

Hi,

Do you have Jaxp classes version 1.1 in your CLASSPATH ?

Regards

Raj


"David Rancour" <david_rancour@hotmail.com> wrote:
>
>Hi all,
>
>I am writing a very basic example of using the SAX api and am running into
>trouble. The class below compiles just fine, but when I try to execute the
>code I get a crazy error. Here is the code and the error:
>
>import org.xml.sax.*;
>import org.xml.sax.helpers.*;
>import java.io.*;
>
>public class xmlEcho extends DefaultHandler
>{
> public void startDocument() throws SAXException
> {
> System.out.println("SAX Event: START Document");
> }
>
> public void endDocument() throws SAXException
> {
> System.out.println("SAX Event: END Document");
> }
>
> public void startElement(String namespaceURI,String localName, String qName,
> Attributes attrs) throws SAXException
> {
> System.out.println("SAX Event: START Element["
> +localName+"]");
> for (int i=0;i < attrs.getLength() ;i++ )
> {
> System.out.println(" ATTRIBUTE "+
> attrs.getLocalName(i)+" VALUE "+
> attrs.getValue(i));
> }
> }
>
> public void endElement(String namespaceURI,String localName,
> String qName) throws SAXException
> {
> System.out.println("SAX Event: END Element["
> +localName+"]");
> }
>
> public void characters(char ch[],int start, int length) throws SAXException
> {
> System.out.print("SAX Event: CHARACTERS[");
> try
> {
> OutputStreamWriter outw = new OutputStreamWriter(System.out);
> outw.write(ch,start,length);
> outw.flush();
> } catch (Exception e)
> {
> e.printStackTrace();
> }
>
> System.out.println("]");
> }
>
> public static void main(String args[])
> {
> System.out.println("Example1 SAX Events");
> try
> {
> XMLReader xr = XMLReaderFactory.createXMLReader();
> xr.setContentHandler(new xmlEcho());
> xr.parse(new InputSource(new FileReader("c:\\web.xml")));
> }
> catch (Exception e)
> {
> e.printStackTrace();
> }
> }
>}
>
>*********ERROR Text
>Exception in thread "main" java.lang.NoClassDefFoundError: org/xml/sax/helpers/DefaultHandler
> at java.lang.ClassLoader.defineClass0(Native Method)
> at java.lang.ClassLoader.defineClass(Unknown Source)
> at java.security.SecureClassLoader.defineClass(Unknown Source)
> at java.net.URLClassLoader.defineClass(Unknown Source)
> at java.net.URLClassLoader.access$100(Unknown Source)
> at java.net.URLClassLoader$1.run(Unknown Source)
> at java.security.AccessController.doPrivileged(Native Method)
> at java.net.URLClassLoader.findClass(Unknown Source)
> at java.lang.ClassLoader.loadClass(Unknown Source)
> at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
> at java.lang.ClassLoader.loadClass(Unknown Source)
> at java.lang.ClassLoader.loadClassInternal(Unknown Source)
>
>How could the program be extending the DefaultHandler class, compile perfectly
>then have a problem locating the class?
>
>Any idea's about what I'm doing wrong here? Thanks alot, I am really stuck.
>
>David Rancour

[Adam]

Hey man,

You just need to add this to your classpath var:
X:\<path to your project,package, or class>\<name of the Parsers project,
package, or class>;


Hope this helps,

[Simeon Leyzerzon]

David,

I changed 2 lines in your code and it works for me:

==> import org.apache.xerces.parsers.*;

and in main

==>XMLReader xr = new SAXParser();

Here is the full code:


import org.apache.xerces.parsers.*;

import org.xml.sax.*;
import org.xml.sax.helpers.*;
import java.io.*;

public class xmlEcho extends DefaultHandler
{
public void startDocument() throws SAXException
{
System.out.println("SAX Event: START Document");
}

public void endDocument() throws SAXException
{
System.out.println("SAX Event: END Document");
}

public void startElement(String namespaceURI,String localName, String qName,
Attributes attrs) throws SAXException
{
System.out.println("SAX Event: START Element["
+localName+"]");
for (int i=0;i < attrs.getLength() ;i++ )
{
System.out.println(" ATTRIBUTE "+
attrs.getLocalName(i)+" VALUE "+
attrs.getValue(i));
}
}

public void endElement(String namespaceURI,String localName,
String qName) throws SAXException
{
System.out.println("SAX Event: END Element["
+localName+"]");
}

public void characters(char ch[],int start, int length) throws SAXException
{
System.out.print("SAX Event: CHARACTERS[");
try
{
OutputStreamWriter outw = new OutputStreamWriter(System.out);
outw.write(ch,start,length);
outw.flush();
} catch (Exception e)
{
e.printStackTrace();
}

System.out.println("]");
}

public static void main(String args[])
{
System.out.println("Example1 SAX Events");
try
{
//XMLReader xr = XMLReaderFactory.createXMLReader();
XMLReader xr = new SAXParser();
xr.setContentHandler(new xmlEcho());
xr.parse(new InputSource(new FileReader("e:\\a.xml")));
}
catch (Exception e)
{
e.printStackTrace();
}
}
}

And here is the output:

Example1 SAX Events
SAX Event: START Document
SAX Event: START Element[hello]
SAX Event: CHARACTERS[
]
SAX Event: START Element[goodbye]
SAX Event: CHARACTERS[good-bye]
SAX Event: END Element[goodbye]
SAX Event: CHARACTERS[
]
SAX Event: END Element[hello]
SAX Event: END Document


for the following xml rile (e:\a.xml):

<hello>
<goodbye>good-bye</goodbye>
</hello>


Hope it's helpful.

Simeon