Writing with XMLStreamWriter
First, you'll create the XML document you will parse. StAX's XMLStreamWriter generates XML. However, one limitation of XMLStreamWriter is that it doesn't necessarily generate well-formed documents—nor are the generated documents necessarily valid. You need to ensure that the XML document generated is well-formed. Listing 1 is an example of a raw XML document generated by XMLStreamWriter.
Try to generate Listing 1's catalog.xml using the XMLStreamWriter API. The code snippets in this section are taken from the XMLWriter.java application, shown in Listing 2. First, you'll import the StAX package classes, like this:
import javax.xml.stream.*;
import javax.xml.stream.events.*;
import javax.xml.stream.XMLOutputFactory;
Your XMLStreamWriter will be obtained from an XMLOutputFactory. So, you first have to create a new XMLOutputFactory:
XMLOutputFactory outputFactory=XMLOutputFactory.newInstance();
Next, create a FileWriter to output the XML document to be generated to an XML file:
FileWriter output=new FileWriter(new File("C:/STAX/catalog.xml"));
Then, create an XMLStreamWriter:
XMLStreamWriter XMLStreamWriterr=outputFactory.createXMLStreamWriter(output);
Now, create a document start with the writeStartDocument() method. Add the encoding and version to be specified in the XML declaration (remember, the encoding specified is not the encoding of the XML document generated). What if you need to specify the XML document's encoding? You would do this when an XMLStreamWriter object is created from an XMLOutputFactory object:
XMLStreamWriter.writeStartDocument("UTF-8","1.0");
Output a comment using writeComment() method:
XMLStreamWriter.writeComment("A OReilly Journal Catalog");
Output a processing instruction using writeProcessingInstruction() method:
XMLStreamWriter.writeProcessingInstruction("catalog","journal='OReilly'");
Output the start of the 'catalog' element using writeStartElement() method (the element prefix and the namespace URI may also be specified in the method):
XMLStreamWriter.writeStartElement("journal","catalog","http://OnJava.com/Journal");
Add 'journal' namespace declaration using writeNamespace() method (the namespace prefix and the namespace URI are specified in the method):
XMLStreamWriter.writeNamespace("journal","http://OnJava.com/Journal");
Add the xsi namespace, again, using the writeNamespace() method:
XMLStreamWriter.writeNamespace("xsi","http://www.w3.org/2001/XMLSchema-instance");
Add the xsi:namespaceSchemaLocation attribute using the writeAttribute() method:
XMLStreamWriter.writeAttribute("xsi:noNamespaceSchemaLocation","file://c:/Schemas/catalog.xsd");
Add the 'publisher' attribute using the writeAttribute() method:
XMLStreamWriter.writeAttribute("publisher","OReilly");
Output the start of the 'journal' element. When a new element is added, the previous element's '>' bracket is also added:
XMLStreamWriter.writeStartElement("journal","journal","http:
//OnJava.com/Journal");
Add the 'date' and 'title' attributes using the writeAttribute() method. Then add the 'article' and 'title' elements using the writeElement() method. Output the text of the 'title' element using writeCharacters() method:
XMLStreamWriter.writeCharacters("Data Binding with XMLBeans");
Any element containing text or sub-elements is required to have a closing tag. Add the closing tag for the 'title' element using writeEndElement() element:
XMLStreamWriter.writeEndElement();
Add the 'author' element and the closing tags for the 'journal' element. The element prefix and namespace URI are not required to be specified in the writeEndElement() method. Similarly add another 'journal' element. Add the closing tags for the 'catalog' element. Output the cached data:
XMLStreamWriter.flush();
Close the XMLStreamWriter.
XMLStreamWriter.close();
That's how to generate catalog.xml
Listing 2 shows the entire Java application, XMLWriter.java. This app may be run as a command line application or in an IDE such as Eclipse.
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