[转]java 异步通信
    1. package intro.nio;
    4. import java.io.IOException;
    5. import java.net.InetAddress;
    6. import java.net.InetSocketAddress;
    7. import java.net.Socket;
    8. import java.nio.ByteBuffer;
    9. import java.nio.CharBuffer;
    10. import java.nio.channels.SelectableChannel;
    11. import java.nio.channels.SelectionKey;
    12. import java.nio.channels.Selector;
    13. import java.nio.channels.ServerSocketChannel;
    14. import java.nio.channels.SocketChannel;
    15. import java.nio.charset.CharacterCodingException;
    16. import java.nio.charset.Charset;
    17. import java.nio.charset.CharsetDecoder;
    18. import java.util.HashMap;
    19. import java.util.Iterator;
    20. import java.util.Set;
    22. public class NBlockingServer {
    23.     int port = 35000;
    24.     int BUFFERSIZE = 1024;
    25.     Selector selector = null;
    26.     ServerSocketChannel serverChannel = null;
    27.     HashMap clientChannelMap = null;// 用来存放每一个客户连接对应的套接字和通道
    29.     public NBlockingServer(int port) {
    30.         this.clientChannelMap = new HashMap();
    31.         this.port = port;
    32.     }
    34.     public void initialize() throws IOException {
    35.         // 初始化，分别实例化一个选择器，一个服务器端可选择通道
    36.         this.selector = Selector.open();
    37.         this.serverChannel = ServerSocketChannel.open();
    38.         this.serverChannel.configureBlocking(false);
    39.         InetAddress localhost = InetAddress.getLocalHost();
    40.         InetSocketAddress isa = new InetSocketAddress(localhost, this.port);
    41.         this.serverChannel.socket().bind(isa);// 将该套接字绑定到服务器某一可用端口
    42.     }
    44.     // 结束时释放资源
    45.     public void finalize() throws IOException {
    46.         this.serverChannel.close();
    47.         this.selector.close();
    48.     }
    50.     // 将读入字节缓冲的信息解码
    51.     public String decode(ByteBuffer byteBuffer) throws CharacterCodingException {
    52.         Charset charset = Charset.forName("ISO-8859-1");
    53.         CharsetDecoder decoder = charset.newDecoder();
    54.         CharBuffer charBuffer = decoder.decode(byteBuffer);
    55.         String result = charBuffer.toString();
    56.         return result;
    57.     }
    59.     // 监听端口，当通道准备好时进行相应操作
    60.     public void portListening() throws IOException, InterruptedException {
    61.         // 服务器端通道注册OP_ACCEPT事件
    62.         SelectionKey acceptKey = this.serverChannel.register(this.selector,
    63.                 SelectionKey.OP_ACCEPT);
    64.         // 当有已注册的事件发生时,select()返回值将大于0
    65.         while (acceptKey.selector().select() > 0) {
    66.             System.out.println("event happened");
    67.             // 取得所有已经准备好的所有选择键
    68.             Set readyKeys = this.selector.selectedKeys();
    69.             // 使用迭代器对选择键进行轮询
    70.             Iterator i = readyKeys.iterator();
    71.             while (i.hasNext()) {
    72.                 SelectionKey key = (SelectionKey) i.next();
    73.                 i.remove();// 删除当前将要处理的选择键
    74.                 if (key.isAcceptable()) {// 如果是有客户端连接请求
    75.                     System.out.println("more client connect in!");
    76.                     ServerSocketChannel nextReady = (ServerSocketChannel) key
    77.                             .channel();
    78.                     // 获取客户端套接字
    79.                     //Socket s = nextReady.accept();
    80.                     SocketChannel sc = nextReady.accept();
    81.                     // 设置对应的通道为异步方式并注册感兴趣事件
    82.                     //s.getChannel().configureBlocking(false);
    83.                     sc.configureBlocking(false);
    84.                     //SelectionKey readWriteKey = s.getChannel().register(
    85.                     SelectionKey readWriteKey = sc.register(
    86.                             this.selector,
    87.                             SelectionKey.OP_READ | SelectionKey.OP_WRITE);
    88.                     // 将注册的事件与该套接字联系起来
    89.                     readWriteKey.attach(sc);
    90.                     // 将当前建立连接的客户端套接字及对应的通道存放在哈希表//clientChannelMap中
    91.                     this.clientChannelMap.put(sc,
    92.                             new ClientChInstance(sc));
    93.                 } else if (key.isReadable()) {// 如果是通道读准备好事件
    94.                     System.out.println("Readable");
    95.                     // 取得选择键对应的通道和套接字
    96.                     SelectableChannel nextReady = (SelectableChannel) key
    97.                             .channel();
    98.                     //Socket socket = (Socket) key.attachment();
    99.                     SocketChannel sc = (SocketChannel) key.attachment();
    100.                     // 处理该事件，处理方法已封装在类ClientChInstance中
    101.                     this.readFromChannel(sc,
    102.                             (ClientChInstance) this.clientChannelMap
    103.                                     .get(sc));
    104.                 } else if (key.isWritable()) {// 如果是通道写准备好事件
    105.                     System.out.println("writeable");
    106.                     // 取得套接字后处理，方法同上
    107.                     //Socket socket = (Socket) key.attachment();
    108.                     SocketChannel sc = (SocketChannel) key.attachment();
    109.                     //SocketChannel channel = (SocketChannel) socket.getChannel();
    110.                     this.writeToChannel(sc, "This is from server!");
    111.                 }
    112.             }
    113.         }
    114.     }
    116.     // 对通道的写操作
    117.     public void writeToChannel(SocketChannel channel, String message)
    118.             throws IOException {
    119.         ByteBuffer buf = ByteBuffer.wrap(message.getBytes());
    120.         int nbytes = channel.write(buf);
    121.     }
    123.     // 对通道的读操作
    124.     public void readFromChannel(SocketChannel channel,
    125.             ClientChInstance clientInstance) throws IOException,
    126.             InterruptedException {
    127.         ByteBuffer byteBuffer = ByteBuffer.allocate(BUFFERSIZE);
    128.         int nbytes = channel.read(byteBuffer);
    129.         byteBuffer.flip();
    130.         String result = this.decode(byteBuffer);
    131.         // 当客户端发出”@exit”退出命令时，关闭其通道
    132.         if (result.indexOf("@exit") >= 0) {
    133.             channel.close();
    134.         } else {
    135.             clientInstance.append(result.toString());
    136.             // 读入一行完毕，执行相应操作
    137.             if (result.indexOf("\n") >= 0) {
    138.                 System.out.println("client input" + result);
    139.                 clientInstance.execute();
    140.             }
    141.         }
    142.     }
    144.     // 该类封装了怎样对客户端的通道进行操作，具体实现可以通过重载execute()方法
    145.     public class ClientChInstance {
    146.         SocketChannel channel;
    147.         StringBuffer buffer = new StringBuffer();
    149.         public ClientChInstance(SocketChannel channel) {
    150.             this.channel = channel;
    151.         }
    153.         public void execute() throws IOException {
    154.             String message = "This is response after reading from channel!";
    155.             writeToChannel(this.channel, message);
    156.             buffer = new StringBuffer();
    157.         }
    159.         // 当一行没有结束时，将当前字窜置于缓冲尾
    160.         public void append(String values) {
    161.             buffer.append(values);
    162.         }
    163.     }
    165.     // 主程序
    166.     public static void main(String[] args) {
    167.         NBlockingServer nbServer = new NBlockingServer(8000);
    168.         try {
    169.             nbServer.initialize();
    170.         } catch (Exception e) {
    171.             e.printStackTrace();
    172.             System.exit(-1);
    173.         }
    174.         try {
    175.             nbServer.portListening();
    176.             System.out.println("heer");
    177.         } catch (Exception e) {
    178.             e.printStackTrace();
    179.         }
    180.     }
    181. }
posted on 2013-03-14 13:37  yeahdwb  阅读(202)  评论(0)    收藏  举报