Merge pull request #26 from GZ-RXP/master

20170305 Assignment - LinkedList and MultiThreadDownload

group11/283091182/src/com/coderising/download/DownloadThread.java

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+package com.coderising.download;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+
+import com.coderising.download.api.Connection;
+
+public class DownloadThread extends Thread{
+
+	Connection conn;
+	int startPos;
+	int endPos;
+	String filePath = null;
+	private boolean finished = false;
+
+	public boolean isFinished() {
+		return finished;
+	}
+	public DownloadThread( Connection conn, int startPos, int endPos,String filePath){
+
+		this.conn = conn;		
+		this.startPos = startPos;
+		this.endPos = endPos;
+		this.filePath = filePath;
+	}
+	public void run(){	
+		File f = new File(this.filePath);
+
+		try {
+			if(!f.exists()){
+				f.createNewFile();
+			}
+			RandomAccessFile raf = new RandomAccessFile(f, "rw");
+			byte[] ba = conn.read(startPos, endPos);
+			System.out.println("["+this.getName()+"]ByteArray length="+ba.length+",endPos-startPos+1="+(endPos-startPos+1));
+			raf.seek(startPos);
+			raf.write(ba, 0, endPos-startPos+1);
+			finished = true;
+			System.out.println("["+this.getName()+"]DownloadThread-startPos="+startPos+"-endPos="+endPos+":download completed");
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+
+	}
+}

group11/283091182/src/com/coderising/download/FileDownloader.java

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+package com.coderising.download;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import com.coderising.download.api.Connection;
+import com.coderising.download.api.ConnectionException;
+import com.coderising.download.api.ConnectionManager;
+import com.coderising.download.api.DownloadListener;
+
+
+public class FileDownloader {
+
+	String url;
+
+	DownloadListener listener;
+
+	ConnectionManager cm;
+
+	private static int DOWNLOAD_SIZE_PER_THREAD = 1024*1000;
+
+	private String destFilePath;
+
+
+	public FileDownloader(String _url) {
+		this.url = _url;
+
+	}
+
+	public FileDownloader(String _url,String destFilePath) {
+		this.url = _url;
+		this.destFilePath = destFilePath;
+	}
+
+	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();	
+			System.out.println("GetLength ="+length);
+
+			File dest = new File(destFilePath);
+			dest.createNewFile();
+			//fill the file with byte array to ensure the size
+//			byte[] ba = new byte[length];
+//			FileOutputStream fos = new FileOutputStream(dest);
+//			fos.write(ba);
+//			fos.flush();
+//			fos.close();
+
+			ArrayList<DownloadThread> threadPool = new ArrayList<DownloadThread>();
+			int numOfThread = length/DOWNLOAD_SIZE_PER_THREAD;
+			if(length%DOWNLOAD_SIZE_PER_THREAD!=0)
+			{
+				numOfThread++;
+			}
+
+			for(int i=0;i<numOfThread;i++){
+				int startPos = i*DOWNLOAD_SIZE_PER_THREAD;
+				int endPos = (i+1)*DOWNLOAD_SIZE_PER_THREAD-1;
+				if(endPos>length-1)
+				{
+					endPos = length-1;
+				}
+				DownloadThread t = new DownloadThread(cm.open(url),startPos,endPos,destFilePath);
+				t.setName("downloadThread_"+i);
+				System.out.println("Initializing Thread:"+t.getName());
+				threadPool.add(t);
+				t.start();
+			}
+			//pooling
+			boolean flag;
+			do{
+				Iterator<DownloadThread> it = threadPool.iterator();
+				flag=true;
+				DownloadThread t;
+				while(it.hasNext()){
+					t = it.next();
+					System.out.println("Thread ="+t.getName()+" has completed?"+t.isFinished());
+					flag = flag && t.isFinished();
+				}
+				if(!flag){
+					System.out.println("=====================AllCompleted="+flag);
+					Thread.sleep(10*1000);
+					continue;
+				}
+			}while(!flag);
+
+		} catch (Exception e) {			
+			throw new RuntimeException("Error occured during download,",e);
+		}finally{
+			if(conn != null){
+				conn.close();
+			}
+		}
+		getListener().notifyFinished();
+	}
+
+	public void setListener(DownloadListener listener) {
+		this.listener = listener;
+	}
+
+
+
+	public void setConnectionManager(ConnectionManager ucm){
+		this.cm = ucm;
+	}
+
+	public DownloadListener getListener(){
+		return this.listener;
+	}
+
+}

group11/283091182/src/com/coderising/download/FileDownloaderTest.java

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+package com.coderising.download;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.coderising.download.api.ConnectionManager;
+import com.coderising.download.api.DownloadListener;
+import com.coderising.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://download.theworld.cn/ver/TWInst_7.0.0.108.exe";//"http://src.onlinedown.net/Public/images/bigsoftimg/120000/q113222.jpg";//
+		String dest = "D:\\bt\\JavaDownload_TWInst_7.0.0.108.exe";
+		FileDownloader downloader = new FileDownloader(url,dest);
+
+
+		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！");
+
+
+
+	}
+
+}

group11/283091182/src/com/coderising/download/api/Connection.java

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+package com.coderising.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();
+}

group11/283091182/src/com/coderising/download/api/ConnectionException.java

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

group11/283091182/src/com/coderising/download/api/ConnectionManager.java

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+package com.coderising.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;	
+}

group11/283091182/src/com/coderising/download/api/DownloadListener.java

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+package com.coderising.download.api;
+
+public interface DownloadListener {
+	public void notifyFinished();
+}

group11/283091182/src/com/coderising/download/impl/ConnectionImpl.java

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+package com.coderising.download.impl;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
+import java.net.ProtocolException;
+import java.net.URL;
+
+import com.coderising.download.api.Connection;
+
+public class ConnectionImpl implements Connection{
+
+	private URL url;
+
+	private int length;
+
+	private InputStream is;
+
+	public ConnectionImpl(String url){
+		try {
+			this.url = new URL(url);
+			this.length = getConnection(this.url).getContentLength();
+		} catch (Exception e) {
+			e.printStackTrace();
+			throw new RuntimeException("Error opening connection.",e);
+		}
+	}
+
+	private HttpURLConnection getConnection(URL url) throws MalformedURLException, IOException, ProtocolException {
+		HttpURLConnection conn = (HttpURLConnection)this.url.openConnection();
+		conn.setRequestMethod("GET");
+		conn.setConnectTimeout(30*1000);
+		return conn;
+	}
+
+	@Override
+	public byte[] read(int startPos, int endPos) throws IOException {
+		byte[] buffer = new byte[1024];
+		int tempLen = 0;
+		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		HttpURLConnection conn = getConnection(url);
+		conn.setRequestProperty("Range", "bytes="+startPos+"-"+endPos);
+		this.is = conn.getInputStream();
+
+		while((tempLen = this.is.read(buffer))!=-1){
+			baos.write(buffer, 0, tempLen);
+		}
+		return baos.toByteArray();
+	}
+
+	@Override
+	public int getContentLength() {
+		return this.length;
+	}
+
+	@Override
+	public void close() {
+		if(this.is!=null)
+		{
+			try {
+				this.is.close();
+				this.url = null;
+			} catch (IOException e) {
+				// Safe to ignore
+				e.printStackTrace();
+			}
+
+		}
+
+	}
+
+}

group11/283091182/src/com/coderising/download/impl/ConnectionManagerImpl.java

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+package com.coderising.download.impl;
+
+import com.coderising.download.api.Connection;
+import com.coderising.download.api.ConnectionException;
+import com.coderising.download.api.ConnectionManager;
+
+public class ConnectionManagerImpl implements ConnectionManager {
+
+	@Override
+	public Connection open(String url) throws ConnectionException {
+		return new ConnectionImpl(url);
+	}
+
+}

group11/283091182/src/com/coding/basic2/Iterator.java

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+package com.coding.basic2;
+
+public interface Iterator {
+	public boolean hasNext();
+	public Object next();
+
+}