jturl.java

来自「Java Pattern Oriented Framework (Jt) 是为了」· Java 代码 · 共 141 行

package Jt;
import java.net.*;
import java.io.*;


/**
 * Class used to handle URLs.
 */

public class JtURL extends JtObject {

    private static final long serialVersionUID = 1L;
    public static final String JtCLASS_NAME = JtURL.class.getName(); 
    public static final String JtDOWNLOAD = "JtDOWNLOAD";

    private String url;
    InputStream stream;
    BufferedInputStream bstream;
    private URL someurl;

    public JtURL() {
    }

    /**
     * Specifies the URL.
     * @param newUrl url
     */

    public void setUrl(String newUrl) {
        url = newUrl;
    }


    /**
     * Returns the URL.
     */
    public String getUrl() {
        return url;
    }


    String download () {
        //int available;
        String line;
        BufferedReader d = null;  
        URLConnection connection;
        StringBuffer result = new StringBuffer();

        if (url == null)
            return (null);

        try {
            someurl = new URL (url);
            connection = someurl.openConnection ();
            connection.connect ();

            //stream = someurl.openStream ();
            stream = connection.getInputStream ();

            d = new BufferedReader (new InputStreamReader (stream));

            while ((line  = d.readLine ()) != null) {           
                //System.out.println (line);
                result.append (line + "\n"); 
            }

            // close streams
            if (stream != null)
                stream.close ();
            if (d != null)
                d.close ();
            return (result.toString ());
        } catch (Exception ex) {
            handleException (ex);
            return (null);
        } 
    } 

    /**
     * Process object messages. 
     * <ul>
     * <li> JtDOWNLOAD - Download the URL and returns its content.
     * </ul>
     * @param message Jt Message    
     */

    public Object processMessage (Object message) {

        String msgid = null;

        JtMessage e = (JtMessage) message;

        if (e == null)
            return null;

        msgid = (String) e.getMsgId ();

        if (msgid == null)
            return null;


        // Remove this object
        if (msgid.equals (JtObject.JtREMOVE)) {
            return (null);     
        }

        if (msgid.equals (JtURL.JtDOWNLOAD)) {
            return (download ());
        }

        return (super.processMessage(message));

    }


    /**
     * Demonstrates the messages processed by JtURL. Usage: java Jt.JtURL url    
     */

    public static void main (String args[]) {
        JtObject main = new JtObject ();
        JtMessage msg;

        if (args.length < 1) {
            System.err.println ("Usage: java Jt.JtURL url");
            System.exit (1);
        }

        main.createObject (JtURL.JtCLASS_NAME, "url");
        main.setValue ("url", "url", args[0]);

        System.err.println ("downloading "+ args[0] + " .....");
        msg = new JtMessage (JtURL.JtDOWNLOAD);

        System.err.println (main.sendMessage ("url", msg));
        main.removeObject ("url");

    }
}