nio加强服务端并发
究了一下Android推送，方式很多，比如用框架或者用第三方服务，在此并不讨论个中优劣。抱着学习的态度，本人不太喜欢用一些现成的东西，所以自己动手实现了一套简单的推送机制。使用TCP长连接，完成服务器端往客户端推送消息的功能。为了加强服务器端的并发性，使用Java NIO+线程池的模式来实现服务器端的推送服务。
服务器端代码如下：
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/* * */package com.intasect.push;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.SelectionKey;import java.nio.channels.Selector;import java.nio.channels.ServerSocketChannel;import java.nio.channels.SocketChannel;import java.util.Iterator;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.atomic.AtomicBoolean;/** * 消息推送服务器 * * @author zengjiantao * @date 2013-4-8 */public class PushServer extends Thread { private static final int BUFFER_SIZE = 1024; /** * 服务器连接通道 */ private ServerSocketChannel serverSocketChannel; /** * 发送缓冲区 */ private final ByteBuffer sendBuf; /** * 端口选择器 */ private Selector selector; /** * 服务器端口 */ private final int mPort; /** * 线程是否结束的标志 */ private final AtomicBoolean shutdown; /** * 发送消息的开关 */ private final AtomicBoolean sendable; /** * 发送消息的内容 */ private String sendMsg; private final ExecutorService executorService; public PushServer(int port) { mPort = port; // 初始化缓冲区 sendBuf = ByteBuffer.allocateDirect(BUFFER_SIZE); if (selector == null) { // 创建新的Selector try { selector = Selector.open(); } catch (final IOException e) { e.printStackTrace(); } } startup(); executorService = Executors.newFixedThreadPool(10); shutdown = new AtomicBoolean(false); sendable = new AtomicBoolean(false); } private void startup() { try { // 打开通道 serverSocketChannel = ServerSocketChannel.open(); // 绑定到本地端口 serverSocketChannel.socket().setSoTimeout(30000); serverSocketChannel.configureBlocking(false); serverSocketChannel.socket().bind(new InetSocketAddress(mPort)); serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT); System.out.println("服务器端口打开成功"); } catch (final IOException e1) { e1.printStackTrace(); } } private void select() { int nums = 0; try { if (selector == null) { return; } nums = selector.select(1000L); } catch (final Exception e) { e.printStackTrace(); } // 如果select返回大于0，处理事件 if (nums > 0) { Iterator<SelectionKey> iterator = selector.selectedKeys() .iterator(); while (iterator.hasNext()) { // 得到下一个Key final SelectionKey key = iterator.next(); iterator.remove(); // 检查其是否还有效 if (!key.isValid()) { continue; } // 处理事件 if (key.isAcceptable()) { executorService.execute(new Accepter(key)); // accept(key); } else if (key.isWritable()) { if (sendable.get()) { executorService.execute(new Sender(key, sendMsg)); } } } if (sendable.get()) { System.out.println("结束推送消息了"); } sendable.set(false); } } /** * 用于连接的Runnable * * @author zengjiantao * @date 2013-4-11 */ class Accepter implements Runnable { private final SelectionKey key; public Accepter(SelectionKey key) { this.key = key; } @Override public void run() { accept(key); } } /** * 用于发送消息的Runnable * * @author zengjiantao * @date 2013-4-11 */ class Sender implements Runnable { private final SelectionKey key; private final String msg; public Sender(SelectionKey key, String msg) { this.key = key; this.msg = msg; } @Override public void run() { send(key, msg); } } /** * 接收客户端 * * @param key * @throws IOException */ private void accept(SelectionKey key) { // 打开通道 try { SocketChannel socketChannel = ((ServerSocketChannel) key.channel()) .accept(); // 绑定到本地端口 socketChannel.socket().setSoTimeout(30000); socketChannel.configureBlocking(false); synchronized (selector) { socketChannel.register(selector, SelectionKey.OP_WRITE, this); } System.out.println("端口打开成功"); } catch (IOException e) { System.out.println("端口打开失败"); e.printStackTrace(); key.cancel(); } } @Override public void run() { // 启动主循环流程 while (!shutdown.get()) { try { select(); try { Thread.sleep(1000L); } catch (final Exception e) { e.printStackTrace(); } } catch (final Exception e) { e.printStackTrace(); } } shutdown(); } /** * 打开发送消息的开关 * * @param msg */ private void send(final String msg) { sendMsg = msg; sendable.set(true); System.out.println("开始推送消息了"); } /** * 向指定连接发送消息 * * @param key * @param msg */ private void send(final SelectionKey key, final String msg) { try { byte[] out = msg.getBytes(); if (out == null || out.length < 1) { return; } synchronized (sendBuf) { sendBuf.clear(); sendBuf.put(out); sendBuf.flip(); } SocketChannel socketChannel = (SocketChannel) key.channel(); socketChannel.write(sendBuf); } catch (final IOException e) { e.printStackTrace(); } } /** * 断开连接 */ public void disConnect() { shutdown.set(true); } /** * 关闭端口选择器 */ private void shutdown() { if (serverSocketChannel != null) { try { serverSocketChannel.close(); while (serverSocketChannel.isOpen()) { try { Thread.sleep(300L); } catch (final InterruptedException e) { e.printStackTrace(); } serverSocketChannel.close(); } System.out.println("端口关闭成功"); } catch (IOException e1) { System.err.println("端口关闭错误:"); e1.printStackTrace(); } finally { serverSocketChannel = null; } } // 关闭端口选择器 if (selector != null) { try { selector.close(); System.out.println("端口选择器关闭成功"); } catch (IOException e) { e.printStackTrace(); } finally { selector = null; } } } public static void main(String[] args) { try { final PushServer server = new PushServer(9999); server.start(); new Thread(new Runnable() { @Override public void run() { while (true) { try { InputStreamReader input = new InputStreamReader( System.in); BufferedReader br = new BufferedReader(input); String sendText = br.readLine(); server.send(sendText); } catch (IOException e) { e.printStackTrace(); } } } }).start(); } catch (Exception e) { e.printStackTrace(); } }} |
客户端代码如下：
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/* * */package com.intasect.push.handle;import java.io.IOException;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.SelectionKey;import java.nio.channels.Selector;import java.nio.channels.SocketChannel;import java.util.Iterator;import java.util.concurrent.atomic.AtomicBoolean;import android.os.Handler;import android.os.Message;import com.intasect.push.utils.Const;/** * * @author zengjiantao * @date 2013-4-8 */public class PushClient extends Thread { private static final int BUFFER_SIZE = 1024; /** * 远程地址 */ private final InetSocketAddress mRemoteAddress; /** * 连接通道 */ private SocketChannel mSocketChannel; /** * 接收缓冲区 */ private final ByteBuffer mReceiveBuf; /** * 端口选择器 */ private Selector mSelector; /** * 线程是否结束的标志 */ private final AtomicBoolean mShutdown; /** * 消息处理 */ private final Handler mHandler; static { java.lang.System.setProperty("java.net.preferIPv4Stack", "true"); java.lang.System.setProperty("java.net.preferIPv6Addresses", "false"); } public PushClient(InetSocketAddress remoteAddress, Handler handler) { mRemoteAddress = remoteAddress; mHandler = handler; // 初始化缓冲区 mReceiveBuf = ByteBuffer.allocateDirect(BUFFER_SIZE); if (mSelector == null) { // 创建新的Selector try { mSelector = Selector.open(); } catch (final IOException e) { e.printStackTrace(); } } mShutdown = new AtomicBoolean(false); } /** * 打开通道 */ private void startup() { try { // 打开通道 mSocketChannel = SocketChannel.open(); // 绑定到本地端口 mSocketChannel.socket().setSoTimeout(30000); mSocketChannel.configureBlocking(false); if (mSocketChannel.connect(mRemoteAddress)) { System.out.println("开始建立连接:" + mRemoteAddress); } mSocketChannel.register(mSelector, SelectionKey.OP_CONNECT | SelectionKey.OP_READ, this); System.out.println("端口打开成功"); } catch (final IOException e1) { e1.printStackTrace(); } } private void select() { int nums = 0; try { if (mSelector == null) { return; } nums = mSelector.select(1000); } catch (final Exception e) { e.printStackTrace(); } // 如果select返回大于0，处理事件 if (nums > 0) { Iterator<SelectionKey> iterator = mSelector.selectedKeys() .iterator(); while (iterator.hasNext()) { // 得到下一个Key final SelectionKey key = iterator.next(); iterator.remove(); // 检查其是否还有效 if (!key.isValid()) { continue; } // 处理事件 try { if (key.isConnectable()) { connect(); } else if (key.isReadable()) { read(key); } } catch (final Exception e) { e.printStackTrace(); key.cancel(); } } } } @Override public void run() { startup(); // 启动主循环流程 while (!mShutdown.get()) { try { // do select select(); try { Thread.sleep(1000); } catch (final Exception e) { e.printStackTrace(); } } catch (final Exception e) { e.printStackTrace(); } } shutdown(); } private void connect() throws IOException { if (isConnected()) { return; } // 完成SocketChannel的连接 mSocketChannel.finishConnect(); while (!mSocketChannel.isConnected()) { try { Thread.sleep(300); } catch (final InterruptedException e) { e.printStackTrace(); } mSocketChannel.finishConnect(); } } public void disConnect() { mShutdown.set(true); } private void shutdown() { if (isConnected()) { try { mSocketChannel.close(); while (mSocketChannel.isOpen()) { try { Thread.sleep(300); } catch (final InterruptedException e) { e.printStackTrace(); } mSocketChannel.close(); } System.out.println("端口关闭成功"); } catch (final IOException e) { System.err.println("端口关闭错误:"); e.printStackTrace(); } finally { mSocketChannel = null; } } else { System.out.println("通道为空或者没有连接"); } // 关闭端口选择器 if (mSelector != null) { try { mSelector.close(); System.out.println("端口选择器关闭成功"); } catch (IOException e) { e.printStackTrace(); } finally { mSelector = null; } } } private void read(SelectionKey key) throws IOException { // 接收消息 final byte[] msg = recieve(); if (msg != null) { String tmp = new String(msg); System.out.println("返回内容："); System.out.println(tmp); if (mHandler != null) { Message message = mHandler.obtainMessage(Const.PUSH_MSG); message.obj = tmp; mHandler.sendMessage(message); } } } private byte[] recieve() throws IOException { if (isConnected()) { int len = 0; int readBytes = 0; synchronized (mReceiveBuf) { mReceiveBuf.clear(); try { while ((len = mSocketChannel.read(mReceiveBuf)) > 0) { readBytes += len; } } finally { mReceiveBuf.flip(); } if (readBytes > 0) { final byte[] tmp = new byte[readBytes]; mReceiveBuf.get(tmp); return tmp; } else { System.out.println("接收到数据为空,重新启动连接"); return null; } } } else { System.out.println("端口没有连接"); } return null; } private boolean isConnected() { return mSocketChannel != null && mSocketChannel.isConnected(); }} |
