NIO demo

src/main/java/nio_demo/demo1/NIOServer.java

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+package nio_demo.demo1;
+
+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.ServerSocketChannel;
+import java.nio.channels.SocketChannel;
+import java.util.Iterator;
+import java.util.Set;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+public class NIOServer {
+
+    public static void main(String[] args) throws IOException {
+        Selector selector = Selector.open();
+        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
+        serverSocketChannel.configureBlocking(false);
+        serverSocketChannel.bind(new InetSocketAddress(8081));
+        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
+
+        while (true) {
+            selector.select();
+            //获取注册的channel
+            Set<SelectionKey> keys = selector.selectedKeys();
+            //遍历所有的key
+            Iterator<SelectionKey> iterator = keys.iterator();
+            while (iterator.hasNext()) {
+                SelectionKey key = iterator.next();
+                iterator.remove();
+                if (key.isValid()) {
+                    //如果通道上有事件发生
+                    if (key.isAcceptable()) {
+                        //获取该通道
+                        ServerSocketChannel acceptServerSocketChannel = (ServerSocketChannel) key.channel();
+                        SocketChannel socketChannel = acceptServerSocketChannel.accept();
+                        socketChannel.configureBlocking(false);
+                        System.out.println(System.currentTimeMillis() + " Accept request from : " + socketChannel.getRemoteAddress());
+                        //同时将SelectionKey标记为可读，以便读取。
+                        SelectionKey readKey = socketChannel.register(selector, SelectionKey.OP_READ);
+                        //利用SelectionKey的attache功能绑定Acceptor 如果有事情，触发Acceptor
+                        //Processor对象为自定义处理请求的类
+                        readKey.attach(new Processor());
+                    } else if (key.isReadable()) {
+                        System.out.println(((SocketChannel)key.channel()).getRemoteAddress() + "触发读事件");
+                        Processor processor = (Processor) key.attachment();
+                        processor.process(key);
+                    }
+                }
+            }
+        }
+    }
+}
+
+/**
+ * Processor类中设置一个线程池来处理请求，
+ * 这样就可以充分利用多线程的优势
+ */
+class Processor {
+    private static final ExecutorService service = Executors.newFixedThreadPool(2);
+
+    public void process(final SelectionKey selectionKey) {
+        service.submit(new Runnable() {
+            @Override
+            public void run() {
+                ByteBuffer buffer = null;
+                SocketChannel socketChannel = null;
+                try {
+                    buffer = ByteBuffer.allocate(1024);
+                    socketChannel = (SocketChannel) selectionKey.channel();
+                    int count = socketChannel.read(buffer);
+                    if (count < 0) {
+                        socketChannel.close();
+                        selectionKey.cancel();
+                        System.out.println("Read ended");
+                    } else if (count == 0) {
+                    }
+                } catch (IOException e) {
+                    try {
+                        socketChannel.close();
+                    } catch (IOException ex) {
+                        ex.printStackTrace();
+                    }
+                    selectionKey.cancel();
+                    e.printStackTrace();
+                }
+                System.out.println(System.currentTimeMillis() + " 接收消息 : " + new String(buffer.array()));
+            }
+        });
+    }
+}

src/main/java/nio_demo/demo1/NioClient.java

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+package nio_demo.demo1;
+
+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 NioClient {
+    public static void main(String[] args) throws IOException, InterruptedException {
+        Selector selector = Selector.open();
+        SocketChannel channel = SocketChannel.open();
+        channel.configureBlocking(false);
+        channel.connect(new InetSocketAddress("127.0.0.1", 8081));
+
+        channel.register(selector, SelectionKey.OP_CONNECT);
+
+        while (true) {
+            selector.select();
+
+            Set<SelectionKey> selectionKeys = selector.selectedKeys();
+            Iterator<SelectionKey> it = selectionKeys.iterator();
+            while (it.hasNext()) {
+                SelectionKey key = it.next();
+                if (key.isConnectable()) {
+                    if (channel.isConnectionPending()) {
+                        if (channel.finishConnect()) {
+                            /*channel.write(ByteBuffer.wrap("1234".getBytes()));
+                            System.out.println(System.currentTimeMillis() + "发送数据 : 1234");
+                            Thread.sleep(5000);
+                            System.out.println(System.currentTimeMillis() + "发送数据 : 5678");
+                            channel.write(ByteBuffer.wrap("5678".getBytes()));*/
+                        }
+                    } else {
+                        channel.connect(new InetSocketAddress("127.0.0.1", 8081));
+                    }
+                }
+
+            }
+        }
+
+    }
+}