echo02.java

《j2ee经典实例详解》的源代码。原书无附带光盘。介绍的是一个在线银行系统的例子。绝对难得

/*
 * Copyright (c) 2005 Sun Microsystems, Inc.  All rights reserved.  U.S.
 * Government Rights - Commercial software.  Government users are subject
 * to the Sun Microsystems, Inc. standard license agreement and
 * applicable provisions of the FAR and its supplements.  Use is subject
 * to license terms.
 *
 * This distribution may include materials developed by third parties.
 * Sun, Sun Microsystems, the Sun logo, Java and J2EE are trademarks
 * or registered trademarks of Sun Microsystems, Inc. in the U.S. and
 * other countries.
 *
 * Copyright (c) 2005 Sun Microsystems, Inc. Tous droits reserves.
 *
 * Droits du gouvernement americain, utilisateurs gouvernementaux - logiciel
 * commercial. Les utilisateurs gouvernementaux sont soumis au contrat de
 * licence standard de Sun Microsystems, Inc., ainsi qu'aux dispositions
 * en vigueur de la FAR (Federal Acquisition Regulations) et des
 * supplements a celles-ci.  Distribue par des licences qui en
 * restreignent l'utilisation.
 *
 * Cette distribution peut comprendre des composants developpes par des
 * tierces parties. Sun, Sun Microsystems, le logo Sun, Java et J2EE
 * sont des marques de fabrique ou des marques deposees de Sun
 * Microsystems, Inc. aux Etats-Unis et dans d'autres pays.
 */


import java.io.*;
import org.xml.sax.*;
import org.xml.sax.helpers.DefaultHandler;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;


public class Echo02 extends DefaultHandler {
    static private Writer out;
    StringBuffer textBuffer;

    public static void main(String[] argv) {
        if (argv.length != 1) {
            System.err.println("Usage: cmd filename");
            System.exit(1);
        }

        // Use an instance of ourselves as the SAX event handler
        DefaultHandler handler = new Echo02();

        // Use the default (non-validating) parser
        SAXParserFactory factory = SAXParserFactory.newInstance();

        try {
            // Set up output stream
            out = new OutputStreamWriter(System.out, "UTF8");

            // Parse the input
            SAXParser saxParser = factory.newSAXParser();
            saxParser.parse(new File(argv[0]), handler);
        } catch (Throwable t) {
            t.printStackTrace();
        }

        System.exit(0);
    }

    //===========================================================
    // SAX DocumentHandler methods
    //===========================================================
    public void startDocument() throws SAXException {
        nl();
        nl();
        emit("START DOCUMENT");
        nl();
        emit("<?xml version='1.0' encoding='UTF-8'?>");
    }

    public void endDocument() throws SAXException {
        nl();
        emit("END DOCUMENT");

        try {
            nl();
            out.flush();
        } catch (IOException e) {
            throw new SAXException("I/O error", e);
        }
    }

    public void startElement(String namespaceURI, String sName, // simple name
        String qName, // qualified name
        Attributes attrs) throws SAXException {
        echoText();
        nl();
        emit("ELEMENT: ");

        String eName = sName; // element name

        if ("".equals(eName)) {
            eName = qName; // not namespaceAware
        }

        emit("<" + eName);

        if (attrs != null) {
            for (int i = 0; i < attrs.getLength(); i++) {
                String aName = attrs.getLocalName(i); // Attr name 

                if ("".equals(aName)) {
                    aName = attrs.getQName(i);
                }

                nl();
                emit("   ATTR: ");
                emit(aName);
                emit("\t\"");
                emit(attrs.getValue(i));
                emit("\"");
            }
        }

        if (attrs.getLength() > 0) {
            nl();
        }

        emit(">");
    }

    public void endElement(String namespaceURI, String sName, // simple name
        String qName // qualified name
    ) throws SAXException {
        echoText();
        nl();
        emit("END_ELM: ");

        String eName = sName; // element name

        if ("".equals(eName)) {
            eName = qName; // not namespaceAware
        }

        emit("</" + eName + ">");
    }

    public void characters(char[] buf, int offset, int len)
        throws SAXException {
        String s = new String(buf, offset, len);

        if (textBuffer == null) {
            textBuffer = new StringBuffer(s);
        } else {
            textBuffer.append(s);
        }
    }

    //===========================================================
    // Utility Methods ...
    //===========================================================
    // Display text accumulated in the character buffer
    private void echoText() throws SAXException {
        if (textBuffer == null) {
            return;
        }

        nl();
        emit("CHARS: |");

        String s = "" + textBuffer;
        emit(s);
        emit("|");
        textBuffer = null;
    }

    // Wrap I/O exceptions in SAX exceptions, to
    // suit handler signature requirements
    private void emit(String s) throws SAXException {
        try {
            out.write(s);
            out.flush();
        } catch (IOException e) {
            throw new SAXException("I/O error", e);
        }
    }

    // Start a new line
    private void nl() throws SAXException {
        String lineEnd = System.getProperty("line.separator");

        try {
            out.write(lineEnd);
        } catch (IOException e) {
            throw new SAXException("I/O error", e);
        }
    }
}