Merge pull request #33 from RalfNick/master

Ralf

group20/925290009/第三次作业/com/coderising/download/DownloadThread.java

@@ -0,0 +1,85 @@
+package com.coderising.download;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+
+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 DownloadThread extends Thread {
+
+
+	ConnectionManager cm;
+	int startPos;
+	int endPos;
+	String url;
+	DownloadListener downloadListener;
+
+	public DownloadThread(ConnectionManager cm, String url, int startPos, int endPos, DownloadListener listener) {
+
+		this.cm = cm;
+		this.startPos = startPos;
+		this.endPos = endPos;
+		this.url = url;
+		this.downloadListener = listener;
+	}
+
+	@Override
+	public void run() {
+
+		Connection conn = null;
+		RandomAccessFile raf = null;
+		// 随机写文件的时候从哪个位置开始写
+		try {
+			conn = cm.open(url,startPos,endPos);
+		} catch (ConnectionException e3) {
+			// TODO Auto-generated catch block
+			e3.printStackTrace();
+		}
+
+		try {
+
+			byte[] byeArr = conn.read(startPos, endPos);
+			System.out.println("----::" + byeArr.length);
+			File file = new File("D:\\111.jpg");
+			synchronized (file) {
+				if (!file.exists()) {
+					file.createNewFile();
+				}
+				raf = new RandomAccessFile(file, "rw");
+			}
+			//raf.setLength(34134);
+			raf.seek(startPos);// 定位文件
+			raf.write(byeArr);
+
+			System.out.println("-------");
+
+		} catch (FileNotFoundException e1) {
+			// TODO Auto-generated catch block
+			e1.printStackTrace();
+		} catch (IOException e) {
+			e.printStackTrace();
+		} finally {
+			try {
+				if (raf != null) {
+					raf.close();
+				}
+
+			} catch (Exception e2) {
+				// TODO: handle exception
+				e2.printStackTrace();
+			}
+			if (conn != null) {
+				conn.close();
+			}
+			if (downloadListener != null) {
+				downloadListener.notifyFinished();
+			}
+
+		}
+	}
+}

group20/925290009/第三次作业/com/coderising/download/FileDownloader.java

@@ -0,0 +1,76 @@
+package com.coderising.download;
+
+import com.coderising.download.api.ConnectionManager;
+import com.coderising.download.api.DownloadListener;
+
+public class FileDownloader {
+
+	String url;
+	DownloadListener listener;
+	ConnectionManager cm;
+	int threadSum = 0;
+
+	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
+
+		// 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;
+
+		int threadNum = 3;
+
+		int length = cm.getContentLength(url);
+		for (int i = 0; i < threadNum; i++) {
+
+			int threadLoadLength = length / threadNum;
+			int startPos = threadLoadLength * i;
+			int endPos;
+			if (i != threadNum - 1) {
+				endPos = threadLoadLength * (i + 1) - 1;
+			} else {
+				endPos = length - 1;
+			}
+			threadSum++;
+			new DownloadThread(cm, this.url, startPos, endPos, new DownloadListener() {
+                @Override
+                public void notifyFinished() {
+                    if ((threadSum--) == 0) {
+                        if (listener != null) {
+                            listener.notifyFinished();
+                        }
+                    }
+                }
+            }).start();
+
+		}
+	}
+
+	public void setListener(DownloadListener listener) {
+		this.listener = listener;
+	}
+
+	public void setConnectionManager(ConnectionManager ucm) {
+		this.cm = ucm;
+	}
+
+	public DownloadListener getListener() {
+		return this.listener;
+	}
+
+}

group20/925290009/第三次作业/com/coderising/download/FileDownloaderTest.java

@@ -0,0 +1,58 @@
+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://img002.21cnimg.com/photos/album/20160326/m600/B920004B5414AE4C7D6F2BAB2966491E.jpeg";
+
+		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！");	
+
+	}
+
+}

group20/925290009/第三次作业/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();
+}

group20/925290009/第三次作业/com/coderising/download/api/ConnectionException.java

@@ -0,0 +1,17 @@
+package com.coderising.download.api;
+
+public class ConnectionException extends Exception {
+
+	/**
+	 * 
+	 */
+	private static final long serialVersionUID = 4776347926322882920L;
+
+	/**
+	 * 
+	 */
+	public ConnectionException(){
+		super();
+	}
+
+}

group20/925290009/第三次作业/com/coderising/download/api/ConnectionManager.java

@@ -0,0 +1,15 @@
+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;
+
+	public int getContentLength(String url);
+
+	Connection open(String url, int startPos, int endPos)
+			throws ConnectionException;	
+}

group20/925290009/第三次作业/com/coderising/download/api/DownloadListener.java

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

group20/925290009/第三次作业/com/coderising/download/impl/ConnectionImpl.java

@@ -0,0 +1,64 @@
+package com.coderising.download.impl;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.HttpURLConnection;
+
+import com.coderising.download.api.Connection;
+
+public class ConnectionImpl implements Connection{
+
+	private HttpURLConnection httpConn;
+	private InputStream inputStream;
+
+	public ConnectionImpl(HttpURLConnection httpconn) {
+		// TODO Auto-generated constructor stub
+		this.httpConn = httpconn;
+	}
+
+
+	//read() 方法有问题
+	@Override
+	public byte[] read(int startPos, int endPos) throws IOException {
+
+		inputStream = httpConn.getInputStream();
+
+		System.out.println(startPos + "----" + endPos);
+		ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+		int len = 0;
+		byte[] by = new byte[1024];
+
+		while((len = inputStream.read(by))!= -1){
+			byteArrayOutputStream.write(by, 0, len);
+		}
+		System.out.println(byteArrayOutputStream.toByteArray().length);
+		return byteArrayOutputStream.toByteArray();
+
+	}
+
+	@Override
+	public int getContentLength() {
+		if (httpConn != null) {
+			return httpConn.getContentLength();
+		}
+		return 0;
+	}
+
+	@Override
+	public void close() {
+		if (inputStream != null) {
+			try {
+				inputStream.close();
+			} catch (IOException e) {
+				// TODO Auto-generated catch block
+				e.printStackTrace();
+			}
+		}
+		if (httpConn != null) {
+			httpConn.disconnect();
+		}
+
+	}
+
+}