Merge pull request #2 from nusubmarine01/master

1

group03/1196051822/3月13日作业的代码/src/download/DownloadThread.java

@@ -0,0 +1,55 @@
+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 java.io.*;
+import java.util.concurrent.locks.Lock;
+
+public class DownloadThread extends Thread {
+
+    ConnectionManager cm;
+    int startPos;
+    int endPos;
+    RandomAccessFile raf;
+    String url;
+    DownloadListener listener;
+
+    public DownloadThread(ConnectionManager cm, int startPos, int endPos, String url, DownloadListener downloadListener) {
+        this.cm = cm;
+        this.startPos = startPos;
+        this.endPos = endPos;
+        this.url = url;
+        this.listener = downloadListener;
+    }
+
+    public void run() {
+        try {
+            Connection conn = cm.open(url);
+            byte[] bytes = conn.read(startPos, endPos);
+            raf = new RandomAccessFile(new File("/Users/byhieg/Desktop/2.png"), "rwd");
+            System.out.println(bytes.length);
+            raf.seek(startPos);
+            raf.write(bytes);
+            if (raf.length() >= (conn.getContentLength() - 2)) {
+                listener.notifyFinished();
+            }
+
+        } catch (IOException | ConnectionException e) {
+            e.printStackTrace();
+        } finally {
+            if (raf != null) {
+                try {
+                    raf.close();
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+
+
+        }
+
+    }
+}

group03/1196051822/3月13日作业的代码/src/download/FileDownloader.java

@@ -0,0 +1,72 @@
+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 java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+
+public class FileDownloader {
+
+    String url;
+
+    DownloadListener listener;
+
+    ConnectionManager cm;
+
+
+    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;
+        try {
+            conn = cm.open(this.url);
+            int length = conn.getContentLength();
+            int threadNum = 3;
+            for (int i = 0 ;i < threadNum; i++) {
+                new DownloadThread(cm, i * length / threadNum, (i + 1) * length / threadNum - 1,url,getListener()).start();
+            }
+        } 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;
+    }
+
+}

group03/1196051822/3月13日作业的代码/src/download/FileDownloaderTest.java

@@ -0,0 +1,59 @@
+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://wx2.sinaimg.cn/mw600/005vbOHfgy1fdfnf5dom0j30rs15ok2l.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！");
+
+
+    }
+
+}

group03/1196051822/3月13日作业的代码/src/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();
+}

group03/1196051822/3月13日作业的代码/src/download/api/ConnectionException.java

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

group03/1196051822/3月13日作业的代码/src/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;	
+}

group03/1196051822/3月13日作业的代码/src/download/api/DownloadListener.java

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

group03/1196051822/3月13日作业的代码/src/download/impl/ConnectionImpl.java

@@ -0,0 +1,66 @@
+package com.coderising.download.impl;
+
+import java.io.*;
+
+import com.coderising.download.api.Connection;
+
+public class ConnectionImpl implements Connection {
+
+    private InputStream inputStream;
+    private BufferedInputStream bufferedInputStream;
+    private int contentLength;
+    public ConnectionImpl(InputStream isr,int contentLength) {
+        this.inputStream = isr;
+        this.contentLength = contentLength;
+    }
+
+    byte[] bytes = new byte[]{};
+
+    @Override
+    public byte[] read(int startPos, int endPos) throws IOException {
+        bufferedInputStream = new BufferedInputStream(inputStream);
+        bytes = new byte[1];
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        int pos = endPos;
+        bufferedInputStream.skip(startPos);
+        while (pos-- > 0) {
+            int flag = bufferedInputStream.read(bytes);
+            if (flag != -1) {
+                baos.write(bytes);
+            }
+        }
+        //单线程读取
+//        int flag = 0;
+//        flag = bufferedInputStream.read(bytes,0,(endPos - startPos));
+//        if (flag != -1){
+//            return bytes;
+//        }
+        return baos.toByteArray();
+    }
+
+    @Override
+    public int getContentLength() {
+        return contentLength;
+    }
+
+    @Override
+    public void close() {
+        if (inputStream != null) {
+            try {
+                inputStream.close();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+
+        if (bufferedInputStream != null) {
+            try {
+                bufferedInputStream.close();
+            } catch (IOException e) {
+                e.printStackTrace();
+            }
+        }
+
+    }
+
+}

group03/1196051822/3月13日作业的代码/src/download/impl/ConnectionManagerImpl.java

@@ -0,0 +1,40 @@
+package com.coderising.download.impl;
+
+import com.coderising.download.api.Connection;
+import com.coderising.download.api.ConnectionException;
+import com.coderising.download.api.ConnectionManager;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLConnection;
+
+public class ConnectionManagerImpl implements ConnectionManager {
+
+
+    InputStream is;
+    int length ;
+    HttpURLConnection connection;
+    String name;
+
+	@Override
+	public Connection open(String url) throws ConnectionException {
+
+        try {
+            URL u = new URL(url);
+            connection = (HttpURLConnection) u.openConnection();
+            length = connection.getContentLength();
+            name = u.getFile();
+            is = u.openStream();
+        } catch (MalformedURLException e) {
+            System.out.println("URL地址不正确");
+        } catch (IOException e) {
+            System.out.println("URL打开流失败");
+        }
+        return new ConnectionImpl(is,length);
+	}
+
+}