Master

group22/1258890344/src/com/coderising/download/DownloadThread.java

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+package com.coderising.download;
+
+import java.io.File;
+
+import com.coderising.download.api.Connection;
+
+public class DownloadThread extends Thread{
+
+	Connection conn;
+	int startPos;
+	int endPos;
+	File file;
+
+	public DownloadThread( Connection conn, int startPos, int endPos,File file){
+		this.conn = conn;		
+		this.startPos = startPos;
+		this.endPos = endPos;
+		this.file=file;
+	}
+
+	public void run(){	
+		try {
+			conn.read(startPos, endPos,file);
+//			conn.close();
+		} catch (Exception e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+	}
+
+}

group22/1258890344/src/com/coderising/download/FileDownloader.java

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+package com.coderising.download;
+
+import java.io.File;
+
+import com.coderising.download.api.Connection;
+import com.coderising.download.api.ConnectionManager;
+import com.coderising.download.api.DownloadListener;
+
+
+public class FileDownloader {
+
+	String url;
+	String path;
+	int threadNum;//线程数
+	int fileLength;//要下载的文件的大小
+	File file;
+
+	DownloadListener listener;
+
+	ConnectionManager cm;
+
+	public FileDownloader(){
+
+	}
+	public FileDownloader(String _url,String _path,int _threadNum) {
+		this.url = _url;
+		this.path=_path;
+		this.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 = cm.open(this.url);//打开网络连接
+
+			file=new File(path);
+			if(!file.getParentFile().exists()){
+				file.getParentFile().mkdirs();
+			}
+			if(file.exists()){
+				file.delete();
+			}
+			file.createNewFile();//创建 文件
+
+
+			fileLength = conn.getContentLength();//获取要下载的文件的大小		
+			System.out.println("文件总长度："+fileLength+"字节");
+
+			int blockSize=fileLength/threadNum; //每个线程平均下载的块的大小
+
+			for(int i=1;i<=threadNum;i++){
+				int startPos=(i-1)*blockSize;
+				int	endPos=i*blockSize-1;
+				if(i==threadNum){
+					endPos=fileLength;
+				}
+				System.out.println("线程"+i+"下载"+startPos+"字节~"+endPos+"字节");
+
+				new Thread(new DownloadThread(conn,startPos,endPos,file)).start();
+
+			}
+
+
+		} catch (Exception e) {			
+			e.printStackTrace();
+		}finally{
+			if(conn != null){
+				conn.close();
+			}
+		}
+
+		while(file.length()<fileLength){
+
+		}
+		listener.notifyFinished();
+
+	}
+
+	public void setListener(DownloadListener listener) {
+		this.listener = listener;
+	}
+
+	public void setConnectionManager(ConnectionManager ucm){
+		this.cm = ucm;
+	}
+
+	public DownloadListener getListener(){
+		return this.listener;
+	}
+
+}

group22/1258890344/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://www.ibm.com/developerworks/cn/opensource/os-ecbug/fig1.jpg";//下载地址
+		String path="D:/test/3.jpg";//保存地址
+		int threadNum=5;//线程数
+
+
+		FileDownloader downloader = new FileDownloader(url,path,threadNum);
+		ConnectionManager cm = new ConnectionManagerImpl();
+
+		downloader.setConnectionManager(cm);//从网络读取
+
+		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！");
+
+
+
+	}
+
+}

group22/1258890344/src/com/coderising/download/api/Connection.java

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+package com.coderising.download.api;
+
+import java.io.File;
+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,File file) throws IOException;
+	/**
+	 * 得到数据内容的长度
+	 * @return
+	 */
+	public int getContentLength();
+
+	/**
+	 * 关闭连接
+	 */
+	public void close();
+}

group22/1258890344/src/com/coderising/download/api/ConnectionException.java

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

group22/1258890344/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;	
+}

group22/1258890344/src/com/coderising/download/api/DownloadListener.java

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

group22/1258890344/src/com/coderising/download/impl/ConnectionImpl.java

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+package com.coderising.download.impl;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.RandomAccessFile;
+import java.net.URL;
+import java.net.URLConnection;
+
+import com.coderising.download.api.Connection;
+
+public class ConnectionImpl implements Connection{
+
+	public URL url;
+	public int length;
+	public InputStream inputStream=null;
+	public RandomAccessFile randomAccessFile=null;
+
+
+	public  ConnectionImpl() {
+		// TODO Auto-generated constructor stub
+	}
+	public ConnectionImpl(URL url){
+		try {
+			this.url=url;
+		} catch (Exception e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+	}
+
+
+	@Override
+	public byte[] read(int startPos, int endPos,File file) throws IOException {
+
+		URLConnection uc=url.openConnection();
+		uc.setRequestProperty("Range", "bytes="+startPos+"-"+endPos);//指定当前一块要获取的开始到结束位置
+
+		inputStream=uc.getInputStream();
+		randomAccessFile=new RandomAccessFile(file, "rwd");
+		randomAccessFile.seek(startPos);//设置写入file文件时从哪里开始写
+
+		byte[] data=new byte[2048];
+		int hasread=0;
+
+		while(-1 != (hasread = inputStream.read(data))){
+			randomAccessFile.write(data, 0, hasread);
+		}
+		return null;
+	}
+
+	@Override
+	public int getContentLength() {
+		try {
+			URLConnection connection=url.openConnection();
+			length=connection.getContentLength();
+		} catch (IOException e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+		return length;
+	}
+
+	@Override
+	public void close() {
+		if(null!=inputStream){
+			try {
+				inputStream.close();
+			} catch (IOException e) {
+				// TODO Auto-generated catch block
+				e.printStackTrace();
+			}
+		}
+		if(null!=randomAccessFile){
+			try {
+				randomAccessFile.close();
+			} catch (IOException e) {
+				// TODO Auto-generated catch block
+				e.printStackTrace();
+			}
+
+		}
+
+	}
+
+}

group22/1258890344/src/com/coderising/download/impl/ConnectionManagerImpl.java

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+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 {
+	URL url;
+	@Override
+	public Connection open(String url) throws ConnectionException {
+		try {
+			this.url=new URL(url);
+			return new ConnectionImpl(this.url);
+		} catch (MalformedURLException e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+		return null;
+	}
+
+}