100分 求java nio非阻塞通信写的聊天程序

Question

小弟一直对java nio服务器端不了解，想求个聊天程序细细了解。
  或者 [email protected]等。

Answer 1

http://dev.csdn.net/article/83226.shtm

Answer 2

服务器的例子：package nio.file;
            
            import java.io.FileInputStream;
            import java.io.IOException;
            import java.net.InetSocketAddress;
            import java.nio.ByteBuffer;
            import java.nio.CharBuffer;
            import java.nio.channels.FileChannel;
            import java.nio.channels.SelectionKey;
            import java.nio.channels.Selector;
            import java.nio.channels.ServerSocketChannel;
            import java.nio.channels.SocketChannel;
            import java.nio.charset.Charset;
            import java.nio.charset.CharsetDecoder;
            import java.util.Iterator;
            
            /**
             * 测试文件下载的NIOServer
             * 
             * @author tenyears.cn
             */
            public class NIOServer {
              static int BLOCK = 4096;
              // 处理与客户端的交互
              public class HandleClient {
                protected FileChannel channel;
                protected ByteBuffer buffer;
                public HandleClient() throws IOException {
                  this.channel = new FileInputStream(filename).getChannel();
                  this.buffer = ByteBuffer.allocate(BLOCK);
                }
                public ByteBuffer readBlock() {
                  try {
                    buffer.clear();
                    int count = channel.read(buffer);
                    buffer.flip();
                    if (count <= 0)
                      return null;
                  } catch (IOException e) {
                    e.printStackTrace();
                  }
                  return buffer;
                }
                public void close() {
                  try {
                    channel.close();
                  } catch (IOException e) {
                    e.printStackTrace();
                  }
                }
              }
            
              protected Selector selector;
              protected String filename = "d:\\bigfile.dat"; // a big file
              protected ByteBuffer clientBuffer = ByteBuffer.allocate(BLOCK);
              protected CharsetDecoder decoder;
            
              public NIOServer(int port) throws IOException {
                selector = this.getSelector(port);
                Charset charset = Charset.forName("GB2312");
                decoder = charset.newDecoder();
              }
            
              // 获取Selector
              protected Selector getSelector(int port) throws IOException {
                ServerSocketChannel server = ServerSocketChannel.open();
                Selector sel = Selector.open();
                server.socket().bind(new InetSocketAddress(port));
                server.configureBlocking(false);
                server.register(sel, SelectionKey.OP_ACCEPT);
                return sel;
              }
            
              // 监听端口
              public void listen() {
                try {
                  for (;;) {
                    selector.select();
                    Iterator<selectionkey></selectionkey> iter = selector.selectedKeys()
                        .iterator();
                    while (iter.hasNext()) {
                      SelectionKey key = iter.next();
                      iter.remove();
                      handleKey(key);
                    }
                  }
                } catch (IOException e) {
                  e.printStackTrace();
                }
              }
            
              // 处理事件
              protected void handleKey(SelectionKey key) throws IOException {
                if (key.isAcceptable()) { // 接收请求
                  ServerSocketChannel server = (ServerSocketChannel) key.channel();
                  SocketChannel channel = server.accept();
                  channel.configureBlocking(false);
                  channel.register(selector, SelectionKey.OP_READ);
                } else if (key.isReadable()) { // 读信息
                  SocketChannel channel = (SocketChannel) key.channel();
                  int count = channel.read(clientBuffer);
                  if (count > 0) {
                    clientBuffer.flip();
                    CharBuffer charBuffer = decoder.decode(clientBuffer);
                    System.out.println("Client >>" + charBuffer.toString());
                    SelectionKey wKey = channel.register(selector,
                        SelectionKey.OP_WRITE);
                    wKey.attach(new HandleClient());
                  } else
                    channel.close();
                  clientBuffer.clear();
                } else if (key.isWritable()) { // 写事件
                  SocketChannel channel = (SocketChannel) key.channel();
                  HandleClient handle = (HandleClient) key.attachment();
                  ByteBuffer block = handle.readBlock();
                  if (block != null)
                    channel.write(block);
                  else {
                    handle.close();
                    channel.close();
                  }
                }
              }
            
              public static void main(String[] args) {
                int port = 12345;
                try {
                  NIOServer server = new NIOServer(port);
                  System.out.println("Listernint on " + port);
                  while (true) {
                    server.listen();
                  }
                } catch (IOException e) {
                  e.printStackTrace();
                }
              }
            }  该代码中，通过一个HandleClient来获取文件的一块数据，每一个客户都会分配一个HandleClient的实例。

Answer 3

下面是客户端请求的代码，也比较简单，模拟100个用户同时下载文件。package nio.file;
            import java.io.IOException;
            import java.net.InetSocketAddress;
            import java.nio.ByteBuffer;
            import java.nio.CharBuffer;
            import java.nio.channels.SelectionKey;
            import java.nio.channels.Selector;
            import java.nio.channels.SocketChannel;
            import java.nio.charset.Charset;
            import java.nio.charset.CharsetEncoder;
            import java.util.Iterator;
            import java.util.concurrent.ExecutorService;
            import java.util.concurrent.Executors;
            
            /**
             * 文件下载客户端
             * @author tenyears.cn
             */
            public class NIOClient {
              static int SIZE = 100;
              static InetSocketAddress ip = new InetSocketAddress("localhost",12345);
              static CharsetEncoder encoder = Charset.forName("GB2312").newEncoder();
              static class Download implements Runnable {
                protected int index;
                public Download(int index) {
                  this.index = index;
                }
            
                public void run() {
                  try {
                    long start = System.currentTimeMillis();
                    SocketChannel client = SocketChannel.open();
                    client.configureBlocking(false);
                    Selector selector = Selector.open();
                    client.register(selector, SelectionKey.OP_CONNECT);
                    client.connect(ip);
                    ByteBuffer buffer = ByteBuffer.allocate(8 * 1024);
                    int total = 0;
                    FOR: for (;;) {
                      selector.select();
                      Iterator<selectionkey></selectionkey> iter = selector.selectedKeys()
                          .iterator();
                      while (iter.hasNext()) {
                        SelectionKey key = iter.next();
                        iter.remove();
                        if (key.isConnectable()) {
                          SocketChannel channel = (SocketChannel) key
                              .channel();
                          if (channel.isConnectionPending())
                            channel.finishConnect();
                          channel.write(encoder.encode(CharBuffer
                              .wrap("Hello from " + index)));
                          channel.register(selector, SelectionKey.OP_READ);
                        } else if (key.isReadable()) {
                          SocketChannel channel = (SocketChannel) key
                              .channel();
                          int count = channel.read(buffer);
                          if (count > 0) {
                            total += count;
                            buffer.clear();
                          } else {
                            client.close();
                            break FOR;
                          }
                        }
                      }
                    }
                    double last = (System.currentTimeMillis() - start) * 1.0 / 1000;
                    System.out.println("Thread " + index + " downloaded " + total
                        + "bytes in " + last + "s.");
                  } catch (IOException e) {
                    e.printStackTrace();
                  }
                }
              }
            
              public static void main(String[] args) throws IOException {
                ExecutorService exec = Executors.newFixedThreadPool(SIZE);
                for (int index = 0; index < SIZE; index++) {
                  exec.execute(new Download(index));
                }
                exec.shutdown();
             }
             
}