非阻塞socket实现android手机与PC的文件传输
项目需要是通过WIFI建立手机和PC的通信,然后自定义一个简单的协议对要传输的文件进行校验,传输的文件是2张3M的图片,要求考虑网络中断情况处理。
我这里采用的是非阻塞socket来实现的,之前查过很多资料,觉得这种比较方便,其实用传统的那种socket也是可以实现的,至于阻塞问题,可以开两个线程,这样保证读取不是同一个线程,也就可以解决。
程序大致是这样的流程,手机端发送一个“filename”字符串给PC,PC校验字符串后返回文件名,然后手机端再把接收到的文件名发送给PC端,进行校验,如果PC端校验成功,那么PC端就开始传输这个文件给手机端,手机端就接收这个文件。至于网络中断的问题,后来发现,只要在服务端发送文件的那一段程序添加try-catch,捕获这个异常,这样服务端的程序就不会死掉,进入等待,等到手机再次和PC端建立连接,那么就可以重新发送文件,这里是重传,而不是续传,后来想过,也只有6M,实际测试过,大概2-3秒就可以传完,重传和续传意义不大,所以就简单的重传了。
程序如下:
PC端:
public class MyServer { private final static Logger logger = Logger.getLogger(MyServer.class.getName()); public static void main(String[] args) { Selector selector = null; ServerSocketChannel serverSocketChannel = null; try { selector = Selector.open(); serverSocketChannel = ServerSocketChannel.open(); serverSocketChannel.configureBlocking(false); serverSocketChannel.socket().setReuseAddress(true); serverSocketChannel.socket().bind(new InetSocketAddress(1991)); serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT); while (selector.select() > 0) { Iterator<SelectionKey> it = selector.selectedKeys().iterator(); while (it.hasNext()) { SelectionKey readyKey = it.next(); it.remove(); SocketChannel socketChannel = null; String string = ""; try { socketChannel = ((ServerSocketChannel) readyKey.channel()).accept(); string = receiveData(socketChannel); logger.log(Level.INFO, string); if(string.equals("filename")){ File f= new File("D:/chz.jpg"); if (f.exists() && f.isFile()){ sendData(socketChannel, "chz.jpg"); }else{ logger.info("file doesn't exist or is not a file"); } } if(string.equals("chz.jpg")){ sendFile(socketChannel, new File("D:/chz.jpg")); } }catch(Exception ex){ logger.log(Level.SEVERE, "1", ex); } finally { try { socketChannel.close(); } catch(Exception ex) { logger.log(Level.SEVERE, "2", ex); } } } } } catch (ClosedChannelException ex) { logger.log(Level.SEVERE, "3", ex); } catch (IOException ex) { logger.log(Level.SEVERE, "4", ex); } finally { try { selector.close(); } catch(Exception ex) { logger.log(Level.SEVERE, "5", ex); } try { serverSocketChannel.close(); } catch(Exception ex) { logger.log(Level.SEVERE, "6", ex); } } } private static String receiveData(SocketChannel socketChannel) throws IOException { String string = null; ByteArrayOutputStream baos = new ByteArrayOutputStream(); ByteBuffer buffer = ByteBuffer.allocate(1024); try { byte[] bytes; int size = 0; while ((size = socketChannel.read(buffer)) >= 0) { buffer.flip(); bytes = new byte[size]; buffer.get(bytes); baos.write(bytes); buffer.clear(); } bytes = baos.toByteArray(); string = new String(bytes); }catch(Exception ex){ logger.log(Level.SEVERE, "7", ex); }finally { try { baos.close(); } catch(Exception ex) { logger.log(Level.SEVERE, "8", ex); } } return string; } private static void sendData(SocketChannel socketChannel, String string) throws IOException { byte[] bytes = string.getBytes(); ByteBuffer buffer = ByteBuffer.wrap(bytes); socketChannel.write(buffer); socketChannel.socket().shutdownOutput(); } private static void receiveFile(SocketChannel socketChannel, File file) throws IOException { FileOutputStream fos = null; FileChannel channel = null; try { fos = new FileOutputStream(file); channel = fos.getChannel(); ByteBuffer buffer = ByteBuffer.allocateDirect(1024); int size = 0; while ((size = socketChannel.read(buffer)) != -1) { buffer.flip(); if (size > 0) { buffer.limit(size); channel.write(buffer); buffer.clear(); } } }catch(Exception ex){ logger.log(Level.SEVERE, "9", ex); } finally { try { channel.close(); } catch(Exception ex) { logger.log(Level.SEVERE, "10", ex); } try { fos.close(); } catch(Exception ex) { logger.log(Level.SEVERE, "11", ex); } } } private static void sendFile(SocketChannel socketChannel, File file) throws IOException { FileInputStream fis = null; FileChannel channel = null; try { fis = new FileInputStream(file); channel = fis.getChannel(); ByteBuffer buffer = ByteBuffer.allocateDirect(1024); int size = 0; while ((size = channel.read(buffer)) != -1) { buffer.rewind(); buffer.limit(size); socketChannel.write(buffer); buffer.clear(); } socketChannel.socket().shutdownOutput(); }catch(Exception ex){ logger.log(Level.SEVERE, "12", ex); } finally { try { channel.close(); } catch(Exception ex) { logger.log(Level.SEVERE, "13", ex); } try { fis.close(); } catch(Exception ex) { logger.log(Level.SEVERE, "14", ex); } } } }
ANDROID端:
public class MainActivity extends Activity { private Button mButton; private EditText et; private static String string; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); et = (EditText)findViewById(R.id.edittext1); et.setText("192.168.1.214"); mButton = (Button)findViewById(R.id.button1); mButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { // TODO Auto-generated method stub string = et.getText().toString(); new Thread(new Runnable() { @Override public void run() { // TODO Auto-generated method stub SocketChannel socketChannel = null; try { socketChannel = SocketChannel.open(); SocketAddress socketAddress = new InetSocketAddress(string, 1991); socketChannel.connect(socketAddress); sendData(socketChannel, "filename"); String string = ""; string = receiveData(socketChannel); if(!string.isEmpty()){ socketChannel = SocketChannel.open(); socketChannel.connect(new InetSocketAddress("192.168.1.214", 1991)); sendData(socketChannel, string); receiveFile(socketChannel, new File("sdcard/afile/"+string)); } } catch (Exception ex) { Log.i("chz", null, ex); } finally { try { socketChannel.close(); } catch(Exception ex) {} } } }).start(); } }); } private void sendData(SocketChannel socketChannel, String string) throws IOException { byte[] bytes = string.getBytes(); ByteBuffer buffer = ByteBuffer.wrap(bytes); socketChannel.write(buffer); socketChannel.socket().shutdownOutput(); } private String receiveData(SocketChannel socketChannel) throws IOException { String string = null; ByteArrayOutputStream baos = new ByteArrayOutputStream(); try { ByteBuffer buffer = ByteBuffer.allocateDirect(1024); byte[] bytes; int count = 0; while ((count = socketChannel.read(buffer)) >= 0) { buffer.flip(); bytes = new byte[count]; buffer.get(bytes); baos.write(bytes); buffer.clear(); } bytes = baos.toByteArray(); string = new String(bytes); // socketChannel.socket().shutdownInput(); } finally { try { baos.close(); } catch(Exception ex) {} } return string; } private static void sendFile(SocketChannel socketChannel, File file) throws IOException { FileInputStream fis = null; FileChannel channel = null; try { fis = new FileInputStream(file); channel = fis.getChannel(); ByteBuffer buffer = ByteBuffer.allocateDirect(1024); int size = 0; while ((size = channel.read(buffer)) != -1) { buffer.rewind(); buffer.limit(size); socketChannel.write(buffer); buffer.clear(); } socketChannel.socket().shutdownOutput(); } finally { try { channel.close(); } catch(Exception ex) {} try { fis.close(); } catch(Exception ex) {} } } private static void receiveFile(SocketChannel socketChannel, File file) throws IOException { FileOutputStream fos = null; FileChannel channel = null; try { fos = new FileOutputStream(file); channel = fos.getChannel(); ByteBuffer buffer = ByteBuffer.allocateDirect(1024); int size = 0; while ((size = socketChannel.read(buffer)) != -1) { buffer.flip(); if (size > 0) { buffer.limit(size); channel.write(buffer); buffer.clear(); } } } finally { try { channel.close(); } catch(Exception ex) {} try { fos.close(); } catch(Exception ex) {} } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); if (id == R.id.action_settings) { return true; } return super.onOptionsItemSelected(item); } }
番外:其实做这个文件传输遇到的最头痛的问题不是程序难不难写,而是wifi通信的建立。最初我是用自己win7的电脑连路由器,然后手机也连路由器做的测试,没有问题,但是后来项目需求是下位机是一台XP的电脑,而且要求点对点建立wifi,所以只能有一端设成wifi热点,另一端连接这个热点。设想很完美,然后找了实验室唯一一台XP电脑测试了两天,都没有能够让我手机连上PC,后来各种问,才知道XP不支持为android创wifi热点,真心坑呀。然后我就想反过来做呗,手机建wifi热点,电脑连,耶果然连上了,可是,明明写好的程序,各种运行不了,最后手机巨热,(我心痛死我的小米,求不黑小米,真心一直用小米,只是导师不给配开发手机,只能用自己手机,哎)所以直接pass这个想法,最后百度了一下,貌似可以接外接硬件设备,比方说360随身wifi硬件,嗯导师终于答应淘宝买一个来测试下,今天买吧。
哦,整个程序参考了两位大神博客:http://www.cnblogs.com/hongten/archive/2012/04/29/java_socket.html
http://blog.csdn.net/kongxx/article/details/7288896尤其是后面这位大神的一个专栏专门讲java socket的,讲得很好。
这个文件传输的整个工程地址:http://download.csdn.net/detail/u012321815/8047863
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