J2ME Http连接例子

以下载一张小图片为例子，一个较为简单的HTTP连接的demo。

支持CMNET及CMWAP两种不同的接入方式，以及在CMWAP接入方式下，过滤移动资费页面。

在6120c上测试通过。

注：若接入点选择错误，可能导致过长时间的等待

 

import java.io.IOException;
import java.io.InputStream;
import javax.microedition.io.Connector;
import javax.microedition.io.HttpConnection;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.StringItem;
import javax.microedition.midlet.MIDlet;

/**
 * HttpDemo
 *
 * @author kf156(亚日)
 *
 */
public class HttpTest extends MIDlet implements CommandListener, Runnable {
    public static final byte WAIT = 0;// 等待

    public static final byte CONNECT = 1;// 连接中

    public static final byte SUCCESS = 2;// 成功

    public static final byte FAIL = 3;// 失败

    int state;// 当前状态

    Display display = Display.getDisplay(this);

    Form form = new Form("HttpTest");

    boolean cmnet = true;// 接入点为cmnet还是cmwap

    StringBuffer sb = new StringBuffer("当前接入方式为:CMNET/n");

    StringItem si = new StringItem(null, sb.toString());

    Command connect = new Command("联网", Command.OK, 1);

    Command change = new Command("改变接入点方式", Command.OK, 2);

    Command exit = new Command("退出", Command.EXIT, 1);

    HttpConnection http;

    String host = "wiki.huihoo.com";

    String path = "/images/9/9c/Java.gif";

    public HttpTest() {
        state = WAIT;// 等待状态
        form.append(si);
        form.addCommand(connect);
        form.addCommand(change);
        form.addCommand(exit);
        form.setCommandListener(this);
    }

    protected void destroyApp(boolean b) {

    }

    protected void pauseApp() {

    }

    protected void startApp() {
        display.setCurrent(form);
    }

    public void commandAction(Command c, Displayable d) {
        if (c == change) {// 改变接入点
            if (isConnect())
                return;

            cmnet = !cmnet;
            form.deleteAll();
            sb.delete(0, sb.length());
            addStr("当前接入方式为:" + (cmnet ? "CMNET" : "CMWAP"));
            form.append(si);

        } else if (c == connect) {// 联网
            if (isConnect())
                return;
            new Thread(this).start();

        } else if (c == exit) {// 退出
            destroyApp(true);
            notifyDestroyed();

        }

    }

    public void run() {
        form.deleteAll();
        sb.delete(0, sb.length());
        addStr("当前接入方式为:" + (cmnet ? "CMNET" : "CMWAP"));
        form.append(si);

        state = CONNECT;
        addStr("网络连接中...");
        InputStream is = null;
        try {
            String url = null;
            url = cmnet ? ("http://" + host + path)
                    : ("http://10.0.0.172:80" + path);
            http = (HttpConnection) Connector.open(url, Connector.READ_WRITE,
                    true);
            if (!cmnet)
                http.setRequestProperty("X-Online-Host", host);

            http.setRequestMethod(HttpConnection.GET);

            String contentType = http.getHeaderField("Content-Type");
            System.out.println(contentType);
            addStr(contentType);

            if (contentType != null
                    && contentType.indexOf("text/vnd.wap.wml") != -1) {// 过滤移动资费页面
                addStr("移动资费页面，过滤！");
                http.close();
                http = null;
                http = (HttpConnection) Connector.open(url,
                        Connector.READ_WRITE, true);
                if (!cmnet)
                    http.setRequestProperty("X-Online-Host", host);
                http.setRequestMethod(HttpConnection.GET);
                contentType = http.getHeaderField("Content-Type");
            }
            addStr("Content-Type=" + contentType);

            int code = http.getResponseCode();
            addStr("HTTP Code :" + code);

            if (code == 200) {
                addStr("网络联网成功，接收数据...");
                is = http.openInputStream();

                Image image = Image.createImage(is);
                addStr("数据接收完毕，显示图片");
                form.append(image);
                // 普通字节数据接收
                // byte[] b = new byte[1024];
                // int len = 0;
                // ByteArrayOutputStream baos = new ByteArrayOutputStream();
                // DataOutputStream dos = new DataOutputStream(baos);
                // while ((len = is.read(b)) != -1) {
                // dos.write(b, 0, len);
                // }
                // dos.close();
                // dos = null;
                // is.close();
                // is = null;
                state = SUCCESS;
                return;
            } else {
                addStr("访问页面失败");
            }
        } catch (IOException e) {
            addStr("联网发生异常：" + e.toString());
            e.printStackTrace();

        } catch (Exception e) {
            addStr("发生异常：" + e.toString());
            e.printStackTrace();

        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                is = null;
            }

            if (http != null)
                try {
                    http.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            http = null;
        }
        state = FAIL;
    }

    /**
     * 判断是否正在连接
     *
     * @return
     */
    private boolean isConnect() {
        if (state == CONNECT) {
            addStr("网络连接中，请稍候...");
            return true;
        }
        return false;
    }

    /**
     * 添加文字
     *
     * @param str
     *            要添加的文字
     */
    private void addStr(String str) {
        sb.append(str + "/n");
        si.setText(sb.toString());
    }
}