Merge pull request #28 from luojunyi/master

第三周 luojunyi  191191717

group26/191191717/src/week3/com/coding/download/DownloadThread.java

@@ -0,0 +1,65 @@
+package week3.com.coding.download;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+
+import week3.com.coding.download.api.Connection;
+
+public class DownloadThread extends Thread
+{
+
+    Connection conn;
+
+    int startPos;
+
+    int endPos;
+
+    public DownloadThread(Connection conn, int startPos, int endPos)
+    {
+
+        this.conn = conn;
+        this.startPos = startPos;
+        this.endPos = endPos;
+    }
+
+    /**
+     * 线程执行方法，启动线程读取一定长度的字节，并写到文件中
+     */
+    public void run()
+    {
+        File f = new File("d:\\test.txt");
+        RandomAccessFile raf = null;
+        try
+        {
+            raf = new RandomAccessFile(f, "rwd");
+            raf.seek(startPos);// 定位当前的指针
+            // raf.close();
+            byte[] bs = conn.read(startPos, endPos);
+            raf.write(bs);
+        }
+        catch (IOException e)
+        {
+            e.printStackTrace();
+        }
+    }
+
+    /**
+     * 资源释放
+     * 
+     * @param raf
+     * @param conn
+     */
+    public void release(RandomAccessFile raf, Connection conn)
+    {
+        try
+        {
+            raf.close();
+        }
+        catch (IOException e)
+        {
+            e.printStackTrace();
+        }
+        conn.close();
+    }
+}

group26/191191717/src/week3/com/coding/download/FileDownloader.java

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+package week3.com.coding.download;
+
+import java.io.IOException;
+
+import week3.com.coding.download.api.Connection;
+import week3.com.coding.download.api.ConnectionException;
+import week3.com.coding.download.api.ConnectionManager;
+import week3.com.coding.download.api.DownloadListener;
+import week3.com.coding.download.impl.ConnectionImpl;
+import week3.com.coding.download.impl.ConnectionManagerImpl;
+
+public class FileDownloader
+{
+
+    String url;
+
+    DownloadListener listener;
+
+    ConnectionManager cm;
+
+    int ThreadNum;
+
+    public FileDownloader(String url, int threadNum)
+    {
+        super();
+        this.url = url;
+        ThreadNum = threadNum;
+    }
+
+    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 = (ConnectionImpl)cm.open(this.url);
+            int length = conn.getContentLength();// 获取文件的长度
+            // 三个线程，每个线程下载长度要平均
+            int blockSize = length / this.ThreadNum;
+            for (int i = 1; i <= this.ThreadNum; i++)
+            {
+                int sPos = (i - 1) * blockSize;
+                int ePos = i * blockSize - 1;
+                // 如果是最后一个，则结束位置等于最后的地方
+                if (i == this.ThreadNum)
+                {
+                    ePos = length;
+                }
+                new DownloadThread(conn, sPos, ePos).start();
+            }
+        }
+        catch (ConnectionException 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;
+    }
+
+    public String getUrl()
+    {
+        return url;
+    }
+
+    public void setUrl(String url)
+    {
+        this.url = url;
+    }
+
+    public ConnectionManager getCm()
+    {
+        return cm;
+    }
+
+    public void setCm(ConnectionManager cm)
+    {
+        this.cm = cm;
+    }
+
+    public int getThreadNum()
+    {
+        return ThreadNum;
+    }
+
+    public void setThreadNum(int threadNum)
+    {
+        ThreadNum = threadNum;
+    }
+
+    public static void main(String[] args)
+        throws ConnectionException, IOException
+    {
+
+        String url = "http://localhost:8088/JSPDemo/test.txt";
+        // ConnectionImpl ci=(ConnectionImpl)cm.open(url);
+        // System.out.println(new String(ci.read(2, 31)));
+        // File f = new File("d:\\test.txt");
+        // RandomAccessFile raf = new RandomAccessFile(f, "rwd");
+        // raf.seek(raf.length());// 定位当前的指针
+
+        FileDownloader downloader = new FileDownloader(url,3);
+        downloader.setConnectionManager(new ConnectionManagerImpl());
+        downloader.execute();
+        // int length = conn.getContentLength();// 获取文件的长度
+        // System.out.println("urlConn: " + length);
+        // int blockSize = length / 3;
+
+        // new DownloadThread(conn, 0, blockSize - 1).start();// 第一个线程
+        // new DownloadThread(conn, blockSize, blockSize * 2 - 1).start();// 第二个线程
+        // new DownloadThread(conn, blockSize * 2 , length - 1).start();// 第三个线程
+    }
+}

group26/191191717/src/week3/com/coding/download/FileDownloaderTest.java

@@ -0,0 +1,66 @@
+package week3.com.coding.download;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import week3.com.coding.download.api.ConnectionManager;
+import week3.com.coding.download.api.DownloadListener;
+import week3.com.coding.download.impl.ConnectionManagerImpl;
+
+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://localhost:8088/JSPDemo/test.txt";
+
+        FileDownloader downloader = new FileDownloader(url,3);
+        ConnectionManager cm = new ConnectionManagerImpl();
+        downloader.setConnectionManager(cm);
+
+        downloader.setListener(new DownloadListener()
+        {
+            @Override
+            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！");
+
+    }
+
+}

group26/191191717/src/week3/com/coding/download/api/Connection.java

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+package week3.com.coding.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();
+
+    /**
+     * 关闭连接
+     */
+    public void close();
+}

group26/191191717/src/week3/com/coding/download/api/ConnectionException.java

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+package week3.com.coding.download.api;
+
+public class ConnectionException extends Exception {
+
+}

group26/191191717/src/week3/com/coding/download/api/ConnectionManager.java

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+package week3.com.coding.download.api;
+
+public interface ConnectionManager {
+    /**
+     * 给定一个url , 打开一个连接
+     * @param url
+     * @return
+     */
+	public Connection open(String url) throws ConnectionException;	
+}

group26/191191717/src/week3/com/coding/download/api/DownloadListener.java

@@ -0,0 +1,6 @@
+package week3.com.coding.download.api;
+
+public interface DownloadListener
+{
+    public void notifyFinished();
+}