Learning and Using Jakarta Digester

<catalog library="somewhere">

   <book>
      <author>Author 1</author>
      <title>Title 1</title>
   </book>

   <book>
      <author>Author 2</author>
      <title>His One Book</title>
   </book>

   <magazine>
      <name>Mag Title 1</name>

      <article page="5">
         <headline>Some Headline</headline>
      </article>

      <article page="9">
         <headline>Another Headline</headline>
      </article>
   </magazine>

   <book>
      <author>Author 2</author>
      <title>His Other Book</title>
   </book>

   <magazine>
      <name>Mag Title 2</name>

      <article page="17">
         <headline>Second Headline</headline>
      </article>
   </magazine>

</catalog>

JavaBean文件：

import java.util.Vector;

public class Catalog {
   private Vector books;
   private Vector magazines;

   public Catalog() {
      books = new Vector();
      magazines = new Vector();
   }

   public void addBook( Book rhs ) {
      books.addElement( rhs );
   }
   public void addMagazine( Magazine rhs ) {
      magazines.addElement( rhs );
   }

   public String toString() {
      String newline = System.getProperty( "line.separator" );
      StringBuffer buf = new StringBuffer();

      buf.append( "--- Books ---" ).append( newline );
      for( int i=0; i<books.size(); i++ ){
         buf.append( books.elementAt(i) ).append( newline );
      }

      buf.append( "--- Magazines ---" ).append( newline );
      for( int i=0; i<magazines.size(); i++ ){
         buf.append( magazines.elementAt(i) ).append( newline );
      }

      return buf.toString();
   }
}

--------------------------------------------------------------------------------

public class Book {
   private String author;
   private String title;

   public Book() {}

   public void setAuthor( String rhs ) { author = rhs; }
   public void setTitle(  String rhs ) { title  = rhs; }

   public String toString() {
      return "Book: Author='" + author + "' Title='" + title + "'";
   }
}

--------------------------------------------------------------------------------

import java.util.Vector;

public class Magazine {
   private String name;
   private Vector articles;

   public Magazine() {
      articles = new Vector();
   }

   public void setName( String rhs ) { name = rhs; }

   public void addArticle( Article a ) {
      articles.addElement( a );
   }

   public String toString() {
      StringBuffer buf = new StringBuffer( "Magazine: Name='" + name + "' ");
      for( int i=0; i<articles.size(); i++ ){
         buf.append( articles.elementAt(i).toString() );
      }
      return buf.toString();
   }
}

--------------------------------------------------------------------------------

public class Article {
   private String headline;
   private String page;

   public Article() {}

   public void setHeadline( String rhs ) { headline = rhs; }
   public void setPage(     String rhs ) { page     = rhs; }

   public String toString() {
      return "Article: Headline='" + headline + "' on page='" + page + "' ";
   }
}

测试文件：

import org.apache.commons.digester.*;

import java.io.*;
import java.util.*;

public class DigesterDriver {

   public static void main( String[] args ) {

      try {
         Digester digester = new Digester();
         digester.setValidating( false );

         digester.addObjectCreate( "catalog", Catalog.class );

         digester.addObjectCreate( "catalog/book", Book.class );
         digester.addBeanPropertySetter( "catalog/book/author", "author" );
         digester.addBeanPropertySetter( "catalog/book/title", "title" );
         digester.addSetNext( "catalog/book", "addBook" );

         digester.addObjectCreate( "catalog/magazine", Magazine.class );
         digester.addBeanPropertySetter( "catalog/magazine/name", "name" );

         digester.addObjectCreate( "catalog/magazine/article", Article.class );
         digester.addSetProperties( "catalog/magazine/article", "page", "page" );
         digester.addBeanPropertySetter( "catalog/magazine/article/headline" );
         digester.addSetNext( "catalog/magazine/article", "addArticle" );

         digester.addSetNext( "catalog/magazine", "addMagazine" );

         File input = new File( args[0] );
         Catalog c = (Catalog)digester.parse( input );

         System.out.println( c.toString() );

      } catch( Exception exc ) {
         exc.printStackTrace();
      }
   }
}