Merge pull request #52 from chhsalex/master

upload homework for 3-12 (code)

Author: Greastate

group08/619057560/3-12/code/com/coderising/download/DownloadThread.java

@@ -0,0 +1,83 @@
+package com.coderising.download;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+
+import com.coderising.download.api.Connection;
+
+public class DownloadThread extends Thread{
+
+	private static final String FILENAME = "test.jpg";
+	
+	Connection conn;
+	int startPos;
+	int endPos;
+	
+	DownloadThreadListener listener;
+	int tag = 0;
+
+	public DownloadThread( Connection conn, int startPos, int endPos){
+		
+		this.conn = conn;		
+		this.startPos = startPos;
+		this.endPos = endPos;
+	}
+	
+	public void setTagAndListener(int tag, DownloadThreadListener listener) {
+		this.tag = tag;
+		this.listener = listener;
+	}
+	
+	public void run(){
+		RandomAccessFile raf = null;
+		int offset = startPos, len;
+		byte[] buffer;
+		try {
+			raf = new RandomAccessFile(FILENAME, "rw");
+			if (raf.length() == 0) {
+				raf.setLength(conn.getContentLength());
+			}
+			raf.seek(startPos);
+			do {
+				len = endPos + 1 - offset;
+				if (len > 10000) {
+					len = 10000;
+				}
+				buffer = conn.read(offset, offset + len - 1);
+				if (buffer == null) {
+					processException(new NullPointerException());
+					return;
+				}
+				raf.write(buffer);
+				offset += len;
+			} while (offset < endPos);
+			if (listener != null) {
+				listener.onFinished(conn, tag, true);
+			}
+		} catch (FileNotFoundException e) {
+			processException(e);
+		} catch (IOException e) {
+			processException(e);
+		} finally {
+			if (raf != null) {
+				try {
+					raf.close();
+				} catch (IOException e) {
+					e.printStackTrace();
+				}
+			}
+		}
+	}
+
+	private void processException(Exception e) {
+		e.printStackTrace();
+		if (listener != null) {
+			listener.onFinished(conn, tag, false);
+		}
+	}
+	
+	public static interface DownloadThreadListener {
+		public void onFinished(Connection conn, int tag, boolean succeeded);
+	}
+}

group08/619057560/3-12/code/com/coderising/download/FileDownloader.java

@@ -0,0 +1,99 @@
+package com.coderising.download;
+
+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 com.coding.basic.Stack;
+
+
+public class FileDownloader {
+	
+	String url;
+	
+	DownloadListener listener;
+	
+	ConnectionManager cm;
+	
+	// Use stack to check if all threads are finished
+	// When a thread is started, an empty Object will be pushed in this stack;
+	// when a thread is finished, an Object will be popped out.
+	private Stack mStack;
+	
+	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
+		
+		Connection conn = null;
+		try {
+			int length = 0;	
+			
+			int threadNum = 3;
+			mStack = new Stack();
+			
+			DownloadThread.DownloadThreadListener dtListener = new DownloadThread.DownloadThreadListener() {
+				
+				@Override
+				public void onFinished(Connection conn, int tag, boolean succeeded) {
+					System.out.println("Thread with tag " + tag + (succeeded?" succeeded":" failed") + " to download");
+					mStack.pop();
+					if (conn != null) {
+						conn.close();
+					}
+					if (mStack.isEmpty()) {
+						listener.notifyFinished();
+					}
+				}
+			};
+			
+			for (int i = 0; i < threadNum; i++) {
+				conn = cm.open(this.url);
+				if (length == 0) {
+					length = conn.getContentLength();
+				}
+				mStack.push(new Object());
+				DownloadThread dt = new DownloadThread(conn,length*i/threadNum,length*(i+1)/threadNum - 1);
+				dt.setTagAndListener(i, dtListener);
+				dt.start();
+				System.out.println("DownloadThread with tag " + i + " created and started");
+			}
+			
+		} 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;
+	}
+	
+}

group08/619057560/3-12/code/com/coderising/download/FileDownloaderTest.java

@@ -0,0 +1,60 @@
+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://localhost:8080/test.jpg";
+		String url = "https://edmullen.net/test/rc.jpg";
+		
+		FileDownloader downloader = new FileDownloader(url);
+
+	
+		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！");
+		
+		
+
+	}
+
+}

group08/619057560/3-12/code/com/coderising/download/api/Connection.java

@@ -0,0 +1,23 @@
+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();
+}

group08/619057560/3-12/code/com/coderising/download/api/ConnectionException.java

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

group08/619057560/3-12/code/com/coderising/download/api/ConnectionManager.java

@@ -0,0 +1,10 @@
+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;	
+}

group08/619057560/3-12/code/com/coderising/download/api/DownloadListener.java

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

group08/619057560/3-12/code/com/coderising/download/impl/ConnectionImpl.java

@@ -0,0 +1,72 @@
+package com.coderising.download.impl;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.net.URLConnection;
+
+import com.coderising.download.api.Connection;
+import com.coderising.download.api.ConnectionException;
+
+public class ConnectionImpl implements Connection{
+	
+	private URLConnection mUrlConnection = null;
+	private InputStream iStream;
+	private int currPos = 0;
+	
+	public ConnectionImpl(URL url) throws ConnectionException{
+		try {
+			mUrlConnection = url.openConnection();
+			mUrlConnection.connect();
+			iStream = mUrlConnection.getInputStream();
+		} catch (IOException e) {
+			mUrlConnection = null;
+			e.printStackTrace();
+			throw new ConnectionException();
+		}
+	}
+
+	@Override
+	public byte[] read(int startPos, int endPos) throws IOException {
+		
+		int bytesLen = endPos - startPos + 1;
+		byte[] buffer = new byte[bytesLen];
+
+		if (currPos < startPos) {
+			iStream.skip(startPos - currPos);
+		} else if (currPos > startPos) {
+			// should not read previous bytes of input stream. 
+			// return null to end this thread.
+			return null;
+		}
+		
+		for (int offset = 0, len; 
+			bytesLen > 0 && (len = iStream.read(buffer, offset, bytesLen)) >= 0;
+			offset += len, bytesLen -= len) ;
+		currPos = endPos + 1;
+		
+		return buffer;
+	}
+
+	@Override
+	public int getContentLength() {
+		if (mUrlConnection != null) {
+			return mUrlConnection.getContentLength();
+		}
+		return 0;
+	}
+
+	@Override
+	public void close() {
+		try {
+			if (iStream != null) {
+				iStream.close();
+			}
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+		currPos = 0;
+		mUrlConnection = null;
+	}
+
+}

group08/619057560/3-12/code/com/coderising/download/impl/ConnectionManagerImpl.java

@@ -0,0 +1,23 @@
+package com.coderising.download.impl;
+
+import java.net.MalformedURLException;
+import java.net.URL;
+
+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 {
+		
+		try {
+			return new ConnectionImpl(new URL(url));
+		} catch (MalformedURLException e) {
+			e.printStackTrace();
+			throw new ConnectionException();
+		}
+	}
+
+}

group08/619057560/3-12/code/com/coding/basic/Iterator.java

@@ -0,0 +1,7 @@
+package com.coding.basic;
+
+public interface Iterator {
+	public boolean hasNext();
+	public Object next();
+	public void remove();
+}