Merge pull request #12 from laibinCN/master

0312 作业

group13/568334413/0312/download/DownloadThread.java

@@ -0,0 +1,44 @@
+package download;
+
+
+import download.api.Connection;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.util.concurrent.CountDownLatch;
+
+public class DownloadThread extends Thread {
+
+    private CountDownLatch countDownLatch;
+    Connection conn;
+    int startPos;
+    int endPos;
+
+    public DownloadThread(Connection conn, int startPos, int endPos, CountDownLatch countDownLatch) {
+        this.countDownLatch = countDownLatch;
+        this.conn = conn;
+        this.startPos = startPos;
+        this.endPos = endPos;
+    }
+
+    @Override
+    public void run() {
+        try {
+            byte[] bytes = conn.read(startPos, endPos);
+            if (bytes == null) {
+                return;
+            }
+            File file = new File("./src/main/resources/1.mp4");
+            RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");
+            randomAccessFile.seek(0);
+            randomAccessFile.write(bytes);
+            randomAccessFile.close();
+            countDownLatch.countDown();
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+    }
+}

group13/568334413/0312/download/FileDownloader.java

@@ -0,0 +1,76 @@
+package download;
+
+import download.api.Connection;
+import download.api.ConnectionManager;
+import download.api.DownloadListener;
+
+import java.util.concurrent.CountDownLatch;
+
+public class FileDownloader {
+
+    String url;
+    DownloadListener listener;
+    ConnectionManager cm;
+    int THREADCOUNT = 4;
+
+    public FileDownloader(String _url) {
+        this.url = _url;
+    }
+
+    public void execute() {
+        // 在这里实现你的代码， 注意： 需要用多线程实现下载
+        // 这个类依赖于其他几个接口, 你需要写这几个接口的实现代码
+        // (1) ConnectionManager , 可以打开一个连接，通过Connection可以读取其中的一段（用startPos, endPos来指定）
+        // (2) DownloadListener, 由于是多线程下载， 调用这个类的客户端不知道什么时候结束，所以你需要实现当所有
+        //     线程都执行完以后， 调用listener的notifiedFinished方法， 这样客户端就能收到通知。
+        // 具体的实现思路：
+        // 1. 需要调用ConnectionManager的open方法打开连接， 然后通过Connection.getContentLength方法获得文件的长度
+        //
+        // 2. 至少启动3个线程下载，  注意每个线程需要先调用ConnectionManager的open方法
+        // 然后调用read方法， read方法中有读取文件的开始位置和结束位置的参数， 返回值是byte[]数组
+        //
+        // 3. 把byte数组写入到文件中
+        //
+        // 4. 所有的线程都下载完成以后， 需要调用listener的notifiedFinished方法
+        // 下面的代码是示例代码， 也就是说只有一个线程， 你需要改造成多线程的。
+        Connection conn = null;
+        try {
+            conn = cm.open(this.url);
+            int length = conn.getContentLength();
+
+            int blockSize = length / THREADCOUNT;
+            final CountDownLatch countDownLatch = new CountDownLatch(THREADCOUNT);
+            for (int threadId = 0; threadId < THREADCOUNT; threadId++) {
+                int startIndex = threadId * blockSize;
+                int endIndex = (threadId + 1) * blockSize - 1;
+                if (threadId == (THREADCOUNT - 1)) {
+                    endIndex = length - 1;
+                }
+                new DownloadThread(conn, startIndex, endIndex, countDownLatch).start();
+            }
+            countDownLatch.await();
+            getListener().notifyFinished();
+
+        } catch (Exception e) {
+            e.printStackTrace();
+        } finally {
+            if (conn != null) {
+                conn.close();
+            }
+        }
+    }
+
+    public void setListener(DownloadListener listener) {
+        this.listener = listener;
+    }
+
+
+    public void setConnectionManager(ConnectionManager ucm) {
+        this.cm = ucm;
+    }
+
+    public DownloadListener getListener() {
+        return this.listener;
+    }
+
+}

group13/568334413/0312/download/FileDownloaderTest.java

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+package download;
+
+
+import download.api.ConnectionManager;
+import download.api.DownloadListener;
+import download.impl.ConnectionManagerImpl;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class FileDownloaderTest {
+    boolean downloadFinished = false;
+
+    @Before
+    public void setUp() throws Exception {
+    }
+
+    @After
+    public void tearDown() throws Exception {
+    }
+
+    @Test
+    public void testDownload() {
+
+//        String url = "http://upload-images.jianshu.io/upload_images/430632-49ce383d76352277.jpg";
+//        String url = "http://img3.91.com/uploads/allimg/130428/32-13042Q63239.jpg";
+//        String url = "http://images.weiphone.net/data/attachment/forum/201703/10/082621it8dfr8frmpbgrdo.png";
+        String url = "http://img.zhxhlm.com/o_1b4sfgd8087os528sg85jjkf.mp4";
+        FileDownloader downloader = new FileDownloader(url);
+        ConnectionManager cm = new ConnectionManagerImpl();
+        downloader.setConnectionManager(cm);
+        downloader.setListener(new DownloadListener() {
+
+            public void notifyFinished() {
+                downloadFinished = true;
+            }
+        });
+        downloader.execute();
+
+        // 等待多线程下载程序执行完毕
+        while (!downloadFinished) {
+            try {
+                System.out.println("还没有下载完成，休眠五秒");
+                //休眠5秒
+                Thread.sleep(5000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+
+        System.out.println("下载完成！");
+
+
+    }
+
+}

group13/568334413/0312/download/api/Connection.java

@@ -0,0 +1,27 @@
+package download.api;
+
+import java.io.IOException;
+
+public interface Connection {
+    /**
+     * 给定开始和结束位置， 读取数据， 返回值是字节数组
+     *
+     * @param startPos 开始位置， 从0开始
+     * @param endPos   结束位置
+     * @return
+     */
+    public byte[] read(int startPos, int endPos) throws IOException;
+
+    /**
+     * 得到数据内容的长度
+     *
+     * @return
+     */
+    public int getContentLength() throws IOException;
+
+
+    /**
+     * 关闭连接
+     */
+    public void close();
+}

group13/568334413/0312/download/api/ConnectionException.java

@@ -0,0 +1,5 @@
+package download.api;
+
+public class ConnectionException extends Exception {
+
+}

group13/568334413/0312/download/api/ConnectionManager.java

@@ -0,0 +1,12 @@
+package download.api;
+
+import java.io.IOException;
+
+public interface ConnectionManager {
+	/**
+	 * 给定一个url , 打开一个连接
+	 * @param url
+	 * @return
+	 */
+	public Connection open(String url) throws ConnectionException, IOException;
+}

group13/568334413/0312/download/api/DownloadListener.java

@@ -0,0 +1,5 @@
+package download.api;
+
+public interface DownloadListener {
+	public void notifyFinished();
+}

group13/568334413/0312/download/impl/ConnectionImpl.java

@@ -0,0 +1,88 @@
+package download.impl;
+
+import download.api.Connection;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.ProtocolException;
+import java.net.URL;
+
+
+public class ConnectionImpl implements Connection {
+
+    private static int RESPONSECODE = 200;
+    private String urlAddress;
+    private InputStream inputStream;
+    private HttpURLConnection httpURLConnection = null;
+    private URL url = null;
+
+    public ConnectionImpl(String urlAddress) {
+        this.urlAddress = urlAddress;
+        try {
+            url = new URL(urlAddress);
+            httpURLConnection = (HttpURLConnection) url.openConnection();
+            httpURLConnection.setDoOutput(true);
+            httpURLConnection.setDoInput(true);
+            httpURLConnection.setConnectTimeout(10000);
+            httpURLConnection.setRequestMethod("GET");
+            httpURLConnection.connect();
+        } catch (ProtocolException e) {
+            e.printStackTrace();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+    }
+
+    public byte[] read(int startPos, int endPos) {
+
+        HttpURLConnection httpURLConnection = null;
+        try {
+            httpURLConnection = (HttpURLConnection) url.openConnection();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        httpURLConnection.setDoOutput(true);
+        httpURLConnection.setDoInput(true);
+        httpURLConnection.setConnectTimeout(10000);
+        byte[] tempByteArray = new byte[0];
+        try {
+            httpURLConnection.setRequestMethod("GET");
+            httpURLConnection.connect();
+            tempByteArray = new byte[httpURLConnection.getContentLength()];
+            InputStream inputStream = httpURLConnection.getInputStream();
+            byte[] buffer = new byte[1024];
+            int len = -1;
+            int index = 0;
+            while ((len = inputStream.read(buffer)) != -1) {
+                System.arraycopy(buffer, 0, tempByteArray, index, len);
+                index = index + len;
+            }
+            inputStream.close();
+        } catch (ProtocolException e) {
+            e.printStackTrace();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+        return tempByteArray;
+    }
+
+    public int getContentLength() throws IOException {
+        int code = httpURLConnection.getResponseCode();
+        if (code == RESPONSECODE) {
+            inputStream = httpURLConnection.getInputStream();
+            return httpURLConnection.getContentLength();
+        }
+        return 0;
+    }
+
+    public void close() {
+        try {
+            inputStream.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}

group13/568334413/0312/download/impl/ConnectionManagerImpl.java

@@ -0,0 +1,20 @@
+package download.impl;
+
+
+import download.api.Connection;
+import download.api.ConnectionException;
+import download.api.ConnectionManager;
+
+import java.io.IOException;
+
+public class ConnectionManagerImpl implements ConnectionManager {
+
+
+    public Connection open(String address) throws ConnectionException, IOException {
+
+        Connection connection = new ConnectionImpl(address);
+
+        return connection;
+    }
+
+}