dracome · dracome · Mar 26, 2017 · Mar 25, 2017
diff --git a/group09/790466157/src/com/coderising/download/DownloadThread.java b/group09/790466157/src/com/coderising/download/DownloadThread.java
@@ -1,42 +1,46 @@
 package com.coderising.download;
 
-
+import com.coderising.download.api.Connection;
+import java.io.File;
+import java.io.IOException;
 import java.io.RandomAccessFile;
+import java.util.concurrent.BrokenBarrierException;
 import java.util.concurrent.CyclicBarrier;
 
-
-//import org.omg.CORBA.portable.InputStream;
-
-import com.coderising.download.api.Connection;
-
 public class DownloadThread extends Thread{
 
 	Connection conn;
 	int startPos;
 	int endPos;
-	CyclicBarrier barrier ;
-	String filePath;
+	String fileName;
+    CyclicBarrier barrier;
 
-	public DownloadThread(CyclicBarrier barrier , Connection conn, int startPos, int endPos , String filePath){
-
-		this.barrier = barrier;
+	public DownloadThread(String name, Connection conn, int startPos, int endPos, String fileName, CyclicBarrier barrier){
+		super(name);
 		this.conn = conn;		
 		this.startPos = startPos;
 		this.endPos = endPos;
-		this.filePath = filePath;
-	}
-	public void run(){	
-		try{
-			System.out.println("begin download startPos="+startPos+",endPos="+endPos);
-			byte[] buffer = conn.read(startPos , endPos);
-			RandomAccessFile file = new RandomAccessFile(filePath, "rw");
-			file.seek(startPos);
-			file.write(buffer, 0, buffer.length);
-			file.close();
-			barrier.await();
-		}catch(Exception e){
-			System.out.println("download error:startPos="+startPos+",endPos="+endPos);
-		}
+		this.fileName = fileName;
+		this.barrier = barrier;
 	}
-
+	public void run(){
+        try (RandomAccessFile raf = new RandomAccessFile(new File(fileName), "rwd")) {
+            raf.seek(startPos);
+            byte[] buf = conn.read(startPos, endPos);
+//            String desc = Thread.currentThread().getName()+"startPos:"+startPos+",length:"+length + "buf size:"+buf.length;
+//            System.out.println(desc);
+            raf.write(buf, 0, buf.length);
+            if (null != barrier) {
+                barrier.await();
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        } catch (BrokenBarrierException e) {
+            e.printStackTrace();
+        } finally {
+            conn.close();
+        }
+    }
 }
diff --git a/group09/790466157/src/com/coderising/download/FileDownloader.java b/group09/790466157/src/com/coderising/download/FileDownloader.java
@@ -1,104 +1,111 @@
 package com.coderising.download;
 
-import java.io.File;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.util.concurrent.CyclicBarrier;
-
 import com.coderising.download.api.Connection;
 import com.coderising.download.api.ConnectionException;
 import com.coderising.download.api.ConnectionManager;
 import com.coderising.download.api.DownloadListener;
 
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
 
 public class FileDownloader {
 
-	String url;
-
-	DownloadListener listener;
+	private String url;
+	private String fileName;
+	private DownloadListener listener;
+	private ConnectionManager cm;
+	private int threadNum = 5;
+	private int length = 0;
+	private Connection conn;
 
-	ConnectionManager cm;
-
-	private static final int THREAD_NUM = 3;
-
-	private static final String BASE_PATH = "C:/Users/Liner/Desktop/Document/Doc";
 
-	boolean isFinished = false;
-
-	public FileDownloader(String _url) {
+	public FileDownloader(String _url, String _fileName) {
 		this.url = _url;
-		File baseFile = new File(BASE_PATH);
-		if(!baseFile.exists()){
-			baseFile.mkdirs();
-		}
+		this.fileName = _fileName;
+
 	}
 
 	public void execute(){
-
-		CyclicBarrier barrier = new CyclicBarrier(THREAD_NUM, new Runnable() {
-
-			@Override
-			public void run() {
-				listener.notifyFinished();
-			}
-		});
-
-			Connection conn = null;
-			try {
-
-				conn = cm.open(this.url);
+		// 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
 
-				int length = conn.getContentLength();
-				String filePath = BASE_PATH + "download."+getFileType(this.url);
-				//System.out.println(filePath);
-
-				File file = new File(filePath);
-				if(!file.exists()){
-					try {
-						file.createNewFile();
-					} catch (IOException e) {
-						e.printStackTrace();
-					}
-				}
-				try{
-					FileOutputStream fos = new FileOutputStream(file);
-					fos.write(new byte[length], 0, length);//占位
-					fos.close();
-				}
-				catch (IOException e) {
-					System.out.println(e.getMessage());
-				}
+        try (RandomAccessFile raf = new RandomAccessFile(new File(fileName), "rwd")) {
+            conn = cm.open(this.url);
+            length = conn.getContentLength();
+            raf.setLength(length);
+            threadPoolDownload();
+//            oneThreadDownload();
+        } catch (FileNotFoundException e) {
+            e.printStackTrace();
+        } catch (IOException e) {
+            e.printStackTrace();
+        } catch (ConnectionException e) {
+            e.printStackTrace();
+        }
 
-				int blockSize = (length % THREAD_NUM == 0 ) ? length / THREAD_NUM : (length / THREAD_NUM + 1);
-				for (int i = 0; i < THREAD_NUM; i++) {
-					int startPos = i * blockSize;
-					int endPos = startPos + blockSize - 1;
-					if(endPos >= length - 1){
-						endPos = length - 1;
-					}
-					new DownloadThread(barrier , conn, startPos, endPos , filePath).start();	
-				}
+    }
 
-			} catch (ConnectionException e) {			
-				System.out.println(e.getMessage());
-			} finally{
-				if(conn != null){
-					conn.close();
-				}
-			}
+	public void oneThreadDownload() {
+        final CyclicBarrier barrier = new CyclicBarrier(1 ,new Runnable() {
+            @Override
+            public void run() {
+                getListener().notifyFinished();
+            }
+        });
+        try {
+            Thread thread = new DownloadThread("oneThread", conn,0,length, fileName, barrier);
+            thread.start();
+        } finally {
+            if (conn != null) {
+                conn.close();
+            }
+        }
+    }
 
-	}
-
-	private String getFileType(String url) {
-		int index = url.lastIndexOf(".");
-		return url.substring(index + 1 , url.length());
-	}
+    public void threadPoolDownload() throws ConnectionException {
+        final CyclicBarrier barrier = new CyclicBarrier(threadNum ,new Runnable() {
+            @Override
+            public void run() {
+                getListener().notifyFinished();  // 栅栏
+            }
+        });
+        ExecutorService threadPool = Executors.newCachedThreadPool();
+        int len = conn.getContentLength();
+        for(int i = 0; i< threadNum; i++)
+        {
+            int start=i*len/ threadNum;
+            int end = (i+1)*len/ threadNum -1;
+            conn = cm.open(this.url);
+            if(i== threadNum -1)
+            {
+                end =len;
+            }
+            Thread thread = new DownloadThread("thread"+i, conn, start, end, fileName, barrier);
+            threadPool.execute(thread);
+        }
+        if (conn != null) {
+            conn.close();
+        }
+    }
 
 	public void setListener(DownloadListener listener) {
 		this.listener = listener;
 	}
-
-
 
 	public void setConnectionManager(ConnectionManager ucm){
 		this.cm = ucm;
@@ -108,4 +115,4 @@ public DownloadListener getListener(){
 		return this.listener;
 	}
 
-}
+}
diff --git a/group09/790466157/src/com/coderising/download/FileDownloaderTest.java b/group09/790466157/src/com/coderising/download/FileDownloaderTest.java
@@ -10,6 +10,7 @@
 
 public class FileDownloaderTest {
 	boolean downloadFinished = false;
+	private double time = 0;
 	@Before
 	public void setUp() throws Exception {
 	}
@@ -21,39 +22,34 @@ public void tearDown() throws Exception {
 	@Test
 	public void testDownload() {
 
-		String url = "https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1488796402240&di=8ca9322617d5338cad61232a06f6ed7a&imgtype=0&src=http%3A%2F%2Fjiangsu.china.com.cn%2Fuploadfile%2F2017%2F0212%2F1486868426284307.jpg";
-
-		FileDownloader downloader = new FileDownloader(url);
+		String url = "http://inews.gtimg.com/newsapp_bt/0/1209438116/1000";
+//		String url = "https://www.baidu.com/img/bd_logo.png";
 
+		FileDownloader downloader = new FileDownloader(url, "test.png");
 
 		ConnectionManager cm = new ConnectionManagerImpl();
 		downloader.setConnectionManager(cm);
-
 		downloader.setListener(new DownloadListener() {
 			@Override
 			public void notifyFinished() {
 				downloadFinished = true;
 			}
-
 		});
-
 
 		downloader.execute();
 
-		// �ȴ����߳����س���ִ�����
+		// 等待多线程下载程序执行完毕
 		while (!downloadFinished) {
 			try {
-				System.out.println("��û��������ɣ���������");
-				//����5��
-				Thread.sleep(5000);
+				System.out.println("还没有下载完成，休眠0.01秒");
+				time += 0.01;
+				//休眠0.01秒
+				Thread.sleep(10);
 			} catch (InterruptedException e) {				
 				e.printStackTrace();
 			}
 		}
-		System.out.println("������ɣ�");
-
-
+		System.out.println("下载完成！耗时"+time+"秒");
 
 	}
-
-}
+}
diff --git a/group09/790466157/src/com/coderising/download/api/Connection.java b/group09/790466157/src/com/coderising/download/api/Connection.java
@@ -4,23 +4,21 @@
 
 public interface Connection {
 	/**
-	 * ������ʼ�ͽ���λ�ã� ��ȡ���ݣ� ����ֵ���ֽ�����
-	 * @param startPos ��ʼλ�ã� ��0��ʼ
-	 * @param endPos ����λ��
+	 * 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;
+    byte[] read(int startPos, int endPos) throws IOException;
+
 	/**
-	 * �õ��������ݵĳ���
+	 * 得到数据内容的长度
 	 * @return
 	 */
-	public int getContentLength();
+    int getContentLength();
 
 	/**
-	 * �ر�����
+	 * 关闭连接
 	 */
-	public void close();
-	public Connection open(Object url);
+    void close();
 }
-
-
diff --git a/group09/790466157/src/com/coderising/download/api/ConnectionException.java b/group09/790466157/src/com/coderising/download/api/ConnectionException.java
@@ -1,5 +1,5 @@
 package com.coderising.download.api;
 
 public class ConnectionException extends Exception {
-	
-}
+
+}
diff --git a/group09/790466157/src/com/coderising/download/api/ConnectionManager.java b/group09/790466157/src/com/coderising/download/api/ConnectionManager.java
@@ -1,10 +1,13 @@
 package com.coderising.download.api;
 
+import java.io.IOException;
+import java.net.ProtocolException;
+
 public interface ConnectionManager {
 	/**
-	 * ����һ��url , ��һ������
+	 * 给定一个url , 打开一个连接
 	 * @param url
 	 * @return
 	 */
-	public Connection open(String url) throws ConnectionException;	
-}
+    Connection open(String url) throws ConnectionException;
+}
diff --git a/group09/790466157/src/com/coderising/download/api/DownloadListener.java b/group09/790466157/src/com/coderising/download/api/DownloadListener.java
@@ -1,5 +1,5 @@
 package com.coderising.download.api;
 
 public interface DownloadListener {
-	public void notifyFinished();
-}
+	void notifyFinished();
+}