一个基于NIO的下载队列实现
来源：互联网 发布：下载隐藏软件 编辑：程序博客网 时间：2024/05/22 04:54
package l.test1.queue.nio;import java.io.File;public interface Task {public String getNetWorkPath();public String getName();/** * * @param file */public void success(File file);/** * * @param netWorkPath */public void fail(String netWorkPath);}package l.test1.queue.nio;import java.io.File;import java.io.IOException;import java.net.InetSocketAddress;import java.net.MalformedURLException;import java.net.URL;import java.nio.channels.SelectionKey;import java.nio.channels.Selector;import java.nio.channels.SocketChannel;import java.util.Iterator;import java.util.LinkedList;import java.util.Queue;public class NIODownLoad extends Thread {private boolean run = true;private static final int DOWN_LOAD_MAX_COUNT = 10;private int downLoadCount = 0;private Selector selector = null;private Queue<Task> queue = new LinkedList<Task>();private NIODownLoad() {setDaemon(true);try {selector = Selector.open();} catch (IOException e) {e.printStackTrace();}}public static final NIODownLoad instance = new NIODownLoad();static{instance.start();}public static NIODownLoad getInstance() {return instance;}@Overridepublic void run() {SelectionKey key = null;while (run) {try {if(selector.select() <=0 ){success();continue;}for (Iterator<SelectionKey> iter = selector.selectedKeys().iterator(); iter.hasNext();) {key = iter.next();iter.remove();if (key.isConnectable()) {connect(key);} else if (key.isReadable()) {read(key);} else if (key.isWritable()) {write(key);}}} catch (IOException e) {if(null != key) {key.cancel();key = null;downLoadCount --;}e.printStackTrace();}}}public void add(Task task) {synchronized (queue) {File file = new File(DownLoadSession.basePath+"/"+task.getName());if(file.exists()) {task.success(file);return;}if(queue.contains(task)) {System.out.println("exist");return;}queue.add(task);if(downLoadCount < DOWN_LOAD_MAX_COUNT) {//instance.interrupt();selector.wakeup();}}}private void connect(SelectionKey key) throws IOException {SocketChannel client = (SocketChannel) key.channel();if (client.finishConnect()) {Task task = (Task) key.attachment();client.register(selector, SelectionKey.OP_WRITE,new DownLoadSession(client, task));}}private void read(SelectionKey key) throws IOException {DownLoadSession session = (DownLoadSession) key.attachment();if (session.read() == -1) {downLoadCount --;success();key.cancel();}}private void write(SelectionKey key) throws IOException {DownLoadSession session = (DownLoadSession) key.attachment();if (session.write() == -1) {key.interestOps(SelectionKey.OP_READ);}}private void success() {if(downLoadCount < DOWN_LOAD_MAX_COUNT) {synchronized (queue) {if(!queue.isEmpty()) {System.out.println("success");Task task = queue.poll();URL url;try {url = new URL(task.getNetWorkPath());int port = url.getPort();if(-1 == port) {port = 80;}InetSocketAddress remote = new InetSocketAddress(url.getHost(),port);try {SocketChannel socket = SocketChannel.open();socket.configureBlocking(false);socket.connect(remote);//socket.finishConnect();socket.register(selector, SelectionKey.OP_CONNECT, task);downLoadCount ++;} catch (IOException e) {e.printStackTrace();}} catch (MalformedURLException e1) {e1.printStackTrace();}}}}}public static void main(String[] args) throws Exception{NIODownLoad down = new NIODownLoad();//for(int i=0;i<10000;i++) {Task task = new T("http://www.baidu.com/img/baidu_sylogo1.gif");down.add(task);down.add(new T("http://www.google.com.hk/intl/zh-CN/images/logo_cn.png"));//}down.start();//down.add(new T("http://www.google.com.hk/intl/zh-CN/images/logo_cn.png"));//////////Task task = new T("http://www.google.com.hk/intl/zh-CN/images/logo_cn.png");//////Task task = new T("http://www.google.com.hk/intl/zh-CN/images/logo_cn.png");//////Task task = new T("http://www.google.com.hk/intl/zh-CN/images/logo_cn.png");//System.out.println(new URL("http://www.google.com.hk").getPath());}}class T implements Task {private String url;private String name;T(String url) {this.url = url;String n = "";try {URL u = new URL(url);String path = u.getPath();if(path.length() == 0) {n = "/index.html";}else {int p = path.lastIndexOf('/');if(p != -1) {n = path.substring(p);}//n = path;}} catch (MalformedURLException e) {e.printStackTrace();}//name = System.currentTimeMillis()+"_"+((int)(Math.random() * 1000))+"_"+n;name = n;}@Overridepublic String getNetWorkPath() {return url;}@Overridepublic String getName() {return name;}@Overridepublic void success(File file) {System.out.println(file.getAbsolutePath());}@Overridepublic void fail(String netWorkPath) {System.out.println("ERROR "+ netWorkPath);}}package l.test1.queue.nio;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.net.MalformedURLException;import java.net.URL;import java.nio.ByteBuffer;import java.nio.channels.FileChannel;import java.nio.channels.SocketChannel;public class DownLoadSession {public static final String basePath = new File("/sdcard/test/photos/").getAbsolutePath();private int bufSize = 512;private SocketChannel client;private Task task;private ByteBuffer buf;private FileChannel fileChannel;private File file;private boolean headEnd = false;private byte[] headCheckCache = new byte[4];private int headCheckIndex = 0;private ByteBuffer head;private File newFile;public DownLoadSession(SocketChannel client, Task task) {this.client = client;this.task = task;buf = ByteBuffer.allocate(bufSize);try {newFile = new File(basePath + "/" + task.getName());file = new File(basePath +"/"+task.getName()+".data");if(!file.getParentFile().exists()) {file.getParentFile().mkdirs();}fileChannel = new FileOutputStream(file).getChannel();builderHead();} catch (FileNotFoundException e) {e.printStackTrace();}}private void builderHead() {try {URL url = new URL(task.getNetWorkPath());String host = url.getHost();String path = url.getPath();if(path.length() == 0) {path = "/";}String query = url.getQuery();StringBuilder builder = new StringBuilder("GET ").append(String.format("%s%s%s", path,null==query?"":"?",null==query?"":query)).append(" HTTP/1.1\r\nHOST: "+host+"\r\nConnection: close\r\n\r\n");head = ByteBuffer.wrap(builder.toString().getBytes());} catch (MalformedURLException e) {e.printStackTrace();}}public int read() throws IOException{try{int readBytes = client.read(buf);if(readBytes > 0) {buf.flip();if(headEnd) {fileChannel.write(buf);} else {readHead();if(buf.hasRemaining()) {fileChannel.write(buf);}}buf.compact();}else if(readBytes == -1) {fileChannel.close();file.renameTo(newFile);task.success(newFile);}return readBytes;}catch(IOException e){fileChannel.close();file.delete();throw e;}}private void readHead() {while(buf.hasRemaining() && !headEnd) {byte b = buf.get();//if(headCheckIndex == 3) {//for(int i=0;i<headCheckIndex;i++) {//headCheckCache[i] = headCheckCache[i+1]; //}//}headCheckCache[headCheckIndex] = b;headEnd = checkHead();if(headEnd) {break;}if(headCheckIndex < 3) {headCheckIndex ++;}else {headCheckIndex = 0;}}}private boolean checkHead() {int i = Math.abs(headCheckIndex - 3);//int i = 0;return headCheckCache[i++ % 4] == '\r' && headCheckCache[i++ % 4] == '\n' && headCheckCache[i++ % 4] == '\r' && headCheckCache[i % 4] == '\n';}public int write() throws IOException{if(null != client && null != head && head.hasRemaining()) {return client.write(head);}return -1;}}
