network connections-secondexample.java

RMS移动商务应用开发

/* License
 * 
 * Copyright 1994-2004 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  
 *  * Redistribution of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 * 
 *  * Redistribution in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *  
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *  
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility. 
 */

import java.io.*;
import javax.microedition.midlet.*;
import javax.microedition.io.*;
import javax.microedition.lcdui.*;

/**
 * An example MIDlet to fetch a page using an HttpConnection.
 */
public class SecondExample extends MIDlet {

    private Display display;
    private String url = "http://www.javacourses.com/hello.txt";

    public SecondExample() {
	display = Display.getDisplay(this);
    }

    /**
     * This will be invoked when we activate the MIDlet.
     */
    public void startApp() {
	// Use the specified URL is overriden in the descriptor
        try {
           downloadPage(url);
        } catch(IOException e) {
           // handle the exception
        }
    }

    private void downloadPage(String url) throws IOException {
	StringBuffer b = new StringBuffer();
        InputStream is = null;
	HttpConnection c = null;
	TextBox t = null;
	try {
	    long len = 0 ;
	    int ch = 0;

            c = (HttpConnection)Connector.open(url);
            is = c.openInputStream();

	    len =c.getLength() ;
	    if ( len != -1) {
		// Read exactly Content-Length bytes
   		for (int i =0 ; i < len ; i++ )
		    if ((ch = is.read()) != -1)
			b.append((char) ch);
	    } else {
                // Read till the connection is closed.
		while ((ch = is.read()) != -1) {
                    len = is.available() ;
		    b.append((char)ch);
		}
	    }
            t = new TextBox("hello again....", b.toString(), 1024, 0);
        }  finally {
           is.close();
           c.close();
        }

	display.setCurrent(t);
    }


    /**
     * Pause, discontinue....
     */
    public void pauseApp() {
    }

    /**
     * Destroy must cleanup everything.
     */
    public void destroyApp(boolean unconditional) {
    }

}