httptest.java

这是手机下载网络图像源码 共初学者参考

/*
 * @(#)HttpTest.java	1.2 03/01/22
 *
 * Copyright (c) 1999-2003 Sun Microsystems, Inc. All rights reserved. 
 * PROPRIETARY/CONFIDENTIAL
 * Use is subject to license terms
 */

package example.http;

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

import java.io.*;

import java.util.*;

/**
 * An example MIDlet to fetch a page using an HttpConnection.
 * Refer to the startApp, pauseApp, and destroyApp
 * methods so see how it handles each requested transition.
 *
 * Note: if you run this inside POSE using a multi-homed PC (with more
 * than one network connections), POSE doesn't know how to resolve
 * host names not connected to the first network card. To solve this,
 * add a line like this in your c:/WINNT/system32/drivers/etc/hosts
 * file:
 *
 * 204.71.202.160  www.yahoo.com
 */
public class HttpTest extends MIDlet implements CommandListener,
        Runnable {
    /** User interface command to exit the current application. */
    private Command exitCommand  = new Command("Exit", Command.EXIT, 2);
    /** User interface command to issue an HTTP GET request. */
    private Command getCommand = new Command("Get", Command.SCREEN, 1);
    /** User interface command to issue an HTTP POST request. */
    private Command postCommand = new Command("Post", Command.SCREEN, 1);
    /** User interface command to issue an HTTP HEAD request. */
    private Command headCommand = new Command("Head", Command.SCREEN, 1);
    /** User interface command to choose a test. */
    private Command chooseCommand = new Command("Choose", Command.SCREEN, 2);
    /** User interface command to Add a new location. */
    private Command addCommand = new Command("Add", Command.SCREEN, 1);
    /** User interface command to save a new location. */
    private Command addSaveCommand = new Command("OK", Command.SCREEN, 1);
    /** User interface command to confirm current operation. */
    private Command okCommand = new Command("OK", Command.OK, 1);
    /** User interface command to abort current operation. */
    private Command cancelCommand = new Command("Cancel", Command.CANCEL, 1);

    /** The current display object. */
    private Display display;
    /** The url to GET from the network. */
    private String url;
    /** Array of target locations. */
    private Vector urls;
    /** User interface list for selection. */
    private List list;
    /** Message area for user entered URl. */
    private TextBox addTextBox;
    /** Current command to proccess. */
    private Command currentCommand;
    /** The current command processing thread. */
    private Thread commandThread;
    /** Current attempt count. */
    private int attempt;
    
    private TextBox t;
    
    private boolean firstTime;

    /** Initialize the MIDlet with a handle to the current display */
    public HttpTest() {
        urls = new Vector();
        urls.addElement("http://www.yahoo.com/");
        urls.addElement("http://www.sun.com/");
        urls.addElement("https://central.sun.net/");
        urls.addElement("https://www.wellsfargo.com");
        urls.addElement("-----------------------");
        urls.addElement("http://jse.east/Telco/HttpTest.txt");
        urls.addElement("http://spiro.eng/");
        urls.addElement("http://spiro.eng:80/");
        urls.addElement("http://localhost:8080/");
        urls.addElement("-----------------------");
        urls.addElement("shttp://host/notsupportedprotocol");
        urls.addElement("http://:8080/missinghost");
        urls.addElement("http://mal\\formed:axyt/url???");
        urls.addElement("http://www.yahoo.com/no/such/page/");
        urls.addElement("http://www.yahoo.com:29999/no/such/port/");
        urls.addElement("http://no.such.site/");
        urls.addElement("http://www.yahoo.com/bad_proxy/");

        url = (String)urls.elementAt(0);
        display = Display.getDisplay(this);
        firstTime = true;
    }

    /**
     * Debug output routine.
     * @param s string to be printed.
     */
    static final void DEBUG(String s) {
        if (true) {
            System.out.println(s);
        }
    }

    /**
     * Converts a time to a string containing the corresponding 
     * date.<br />
     * <b>NOTE:</b> This is here only because the J2ME date class does not
     * implement toString() in any meaningful way.
     * <p />
     * @param time time to be converted
     * @return a string representation of the time in
     *         the form "dayOfWeek, day mon year hour:min:sec GMT"
     */ 
    private String time2str(long time) {
        Calendar c = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
        c.setTime(new Date(time));
        return c.toString();
    }

    /**
     * Start creates the thread to do the timing.
     * It should return immediately to keep the dispatcher
     * from hanging.
     */
    public void startApp() {
        if(firstTime) {
            // Use the specified URL is overriden in the descriptor
            String u = getAppProperty("HttpTest-Url");
            if (u != null) {
                url = u;
            }            
            mainScreen();
            firstTime = false;
        } else {
            display.setCurrent(t);
        }
            
    }
    /**
     * Display the main screen.
     */
    void mainScreen() {
        String s = "URL = " + url +
            ". Press Get or Post to fetch it, or Choose to " +
            "use another URL";
        t = new TextBox("Http Test", s, s.length(), 0);
        setCommands(t, false);
        display.setCurrent(t);
    }
    /**
     * Pick a screen.
     */
    void chooseScreen() {
        list = new List("Choose URL", Choice.EXCLUSIVE);
        for (int i = 0; i < urls.size(); i++) {
            list.append((String)urls.elementAt(i), null);
        }
        setCommands(list, true);
	display.setCurrent(list);
    }
    /**
     * Add another screen.
     */
    void addScreen() {
        addTextBox = new TextBox("New URL", "http://", 200, 0);
        addTextBox.addCommand(addSaveCommand);
        addTextBox.addCommand(cancelCommand);
        addTextBox.setCommandListener(this);
	display.setCurrent(addTextBox);
    }
    /**
     * Read the content of the page. Don't care about the response
     * headers.
     * @param request type of HTTP request (GET or POST)
     */
    private void readContents(String request) {
	StringBuffer b = new StringBuffer();
        ++ attempt;
        b.append("attempt " + attempt + " content of " 
                 + request + " " + url + "\n");
	HttpConnection c = null;
        OutputStream os = null;
        InputStream is = null;
	TextBox t = null;

	try {
	    long len = -1;
	    int ch = 0;
            long count = 0;
            int rc;

            DEBUG(request + " Page: " + url); 
            c = (HttpConnection)Connector.open(url);
            DEBUG("c= " + c);

            c.setRequestMethod(request);

            c.setRequestProperty("foldedField",
                 "first line\r\n second line\r\n third line");

            if (request == HttpConnection.POST) {
                String m = "Test POST text.";
                DEBUG("Posting: " + m);
                os = c.openOutputStream();
                os.write(m.getBytes());
                os.close();
            }

            rc = c.getResponseCode();
            if (rc != HttpConnection.HTTP_OK) {
                b.append("Response Code: " + c.getResponseCode() + "\n");
                b.append("Response Message: " + c.getResponseMessage() +
                         "\n\n");
            }

	    is = c.openInputStream();

            DEBUG("is = " + is);
            if (c instanceof HttpConnection) {
                len = ((HttpConnection)c).getLength();
            }
            DEBUG("len = " + len);
	    if (len != -1) {
		// Read exactly Content-Length bytes
                DEBUG("Content-Length: " + len);

		for (int i = 0; i < len; i++) {
		    if ((ch = is.read()) != -1) {
			if (ch <= ' ') {
                            ch = ' ';
                        }
			b.append((char) ch);
                        count ++;
                        if (count > 200) {
                            break;
                        }
		    }
                }
	    } else {
                byte data[] = new byte[100];
                int n = is.read(data, 0, data.length);
                for (int i = 0; i < n; i++) {
                    ch = data[i] & 0x000000ff;
		    b.append((char)ch);
		}
	    }
	    try {
                if (is != null) {
                    is.close();
                }
                if (c != null) {
                    c.close();
                }
	    } catch (Exception ce) {
		DEBUG("Error closing connection");
	    }

	    try {
		len = is.available();
		DEBUG("Inputstream failed to throw IOException after close");
	    } catch (IOException io) {
                DEBUG("expected IOException (available())");
                io.printStackTrace();
		// Test to make sure available() is only valid while
		// the connection is still open.,
	    }

	    t = new TextBox("Http Test", b.toString(), b.length(), 0);
            is = null;
            c = null;
	} catch (IOException ex) {
            ex.printStackTrace();
            DEBUG(ex.getClass().toString());
            DEBUG(ex.toString());
	    DEBUG("Exception reading from http");
	    if (c != null) {
		try {
		    String s = null;
                    if (c instanceof HttpConnection) {
                        s = ((HttpConnection)c).getResponseMessage();
                    }
		    DEBUG(s);
		    if (s == null)
			s = "No Response message";
		    t = new TextBox("Http Error", s, s.length(), 0);
		} catch (IOException e) {
		    e.printStackTrace();
		    String s = e.toString();
		    DEBUG(s);
		    if (s == null)
			s = ex.getClass().getName();
		    t = new TextBox("Http Error", s, s.length(), 0);