Android使用NIO开发客户端

简介

NIO 是New IO 的简称，在jdk1.4 里提供的新api 。Sun 官方标榜的特性如下： 为所有的原始类型提供(Buffer)缓存支持。字符集编码解码解决方案。 Channel ：一个新的原始I/O 抽象。 支持锁和内存映射文件的文件访问接口。 提供多路(non-bloking) 非阻塞式的高伸缩性网络I/O 。

SocketUtil.java

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.Set;public class NIOSocketUtil extends Thread {    private Selector selector = null;    private SocketChannel client = null;    private static int CONNECT_TIMEOUT = 10000;    private static int READ_TIMEOUT = 10000;    private static int RECONNECT_TIME = 10000;    private final byte CONNECT = 1;    private final byte RUNNING = 2;    private byte STATE = CONNECT;    private boolean onWork;// 是否工作状态    static {        java.lang.System.setProperty("java.net.preferIPv6Addresses", "false");    };    public static int STATUS_OK = 1000;    public static int STATUS_FAIL = 1001;    private String ip = "127.0.0.1";    private int port = 9527;    private ConnectListener connectListener;    private DataCallbackListener dataCallbackListener;    private static final int BLOCK = 102400;    private ByteBuffer readBuffer = ByteBuffer.allocate(BLOCK);// 100kb缓冲区    public NIOSocketUtil(String ip, int port) {        this.ip = ip;        this.port = port;        onWork = true;    }    public boolean isReady() {        return STATE == RUNNING;    }    public void stopWork() {        onWork = false;        closeKey(null);    }    @Override    public void run() {        // TODO Auto-generated method stub        while (onWork) {            switch (STATE) {            case CONNECT:                connect();                break;            case RUNNING:                running();                break;            }        }    }    private void running() {        SelectionKey key = null;        try {            while (selector.select() > 0) {                Set<SelectionKey> keys = selector.selectedKeys();                Iterator<SelectionKey> iterator = keys.iterator();                while (iterator.hasNext()) {                    key = iterator.next();                    iterator.remove();                    read(key);                }            }        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();            closeKey(key);        }    }    private final void read(SelectionKey selectionKey) throws IOException {        if (selectionKey.isReadable()) {            SocketChannel client = (SocketChannel) selectionKey.channel();            // 如果缓冲区过小的话那么信息流会分成多次接收            int actual = client.read(readBuffer);            if (actual > 0) {                readBuffer.flip();                int limit = readBuffer.limit();                byte[] data = new byte[limit];                readBuffer.get(data);                readBuffer.clear();// 清空                // process data                if (dataCallbackListener != null)                    dataCallbackListener.callback(data);            }        }    }    public final boolean write(byte[] data) {        try {            if (STATE == RUNNING && client != null && client.isConnected()) {                ByteBuffer buffer = ByteBuffer.wrap(data);                int size = buffer.limit();                // 此处需加中途断开逻辑，下次再继续发送数据包                int actually = client.write(buffer);                if (actually == size)                    return true;            }        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();            closeKey(null);        }        return false;    }    private void connect() {        try {            selector = Selector.open();            InetSocketAddress isa = new InetSocketAddress(ip, port);            client = SocketChannel.open();            // 设置连超时            client.socket().connect(isa, CONNECT_TIMEOUT);            // 设置读超时            client.socket().setSoTimeout(READ_TIMEOUT);            client.configureBlocking(false);            client.register(selector, SelectionKey.OP_READ);            if (client.isConnected()) {                // 连接成功开始监听服务端消息                // 发送一个验证数据包到服务器进行验证                STATE = RUNNING;                if (connectListener != null)                    connectListener.connect(STATUS_OK);            } else {                // 关闭通道过60S重新开始连接                if (connectListener != null)                    connectListener.connect(STATUS_FAIL);                StringBuffer buffer = new StringBuffer("服务器连接失败");                buffer.append(RECONNECT_TIME / 1000);                buffer.append("秒后再尝试连接");                if (connectListener != null)                    connectListener.error(buffer.toString());                closeKey(null);// 关闭通道                Wait(RECONNECT_TIME);            }        } catch (Exception e) {            // TODO Auto-generated catch block            // 有异常关闭通道过60S重新开始连接            e.printStackTrace();            StringBuffer buffer = new StringBuffer("连接出错");            buffer.append(RECONNECT_TIME / 1000);            buffer.append("秒后再尝试连接");            if (connectListener != null)                connectListener.error(buffer.toString());            closeKey(null);// 关闭通道            Wait(RECONNECT_TIME);        }    }    private void closeKey(SelectionKey key) {        STATE = CONNECT;        try {            if (client != null) {                client.socket().close();                client.close();                client = null;            }            if (selector != null) {                selector.close();                selector = null;            }        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        if (key != null) {            key.cancel();            try {                key.channel().close();            } catch (Exception e) {                // TODO Auto-generated catch block                e.printStackTrace();                StringBuffer buffer = new StringBuffer("连接断开");                buffer.append(RECONNECT_TIME / 1000);                buffer.append("秒后再尝试连接");                if (connectListener != null)                    connectListener.error(buffer.toString());                Wait(RECONNECT_TIME);            }        }    }    private synchronized void Wait(long millis) {        try {            wait(millis);        } catch (InterruptedException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    public void setDataCallbackListener(            DataCallbackListener dataCallbackListener) {        this.dataCallbackListener = dataCallbackListener;    }    public void setConnectListener(ConnectListener connectListener) {        this.connectListener = connectListener;    }    public interface ConnectListener {        public void connect(int status);        public void error(String msg);    }    public interface DataCallbackListener {        public void callback(byte[] data);    }}