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| 1 | +package com.bruis.learnnetty.nio.demo01; |
| 2 | + |
| 3 | +import java.net.InetSocketAddress; |
| 4 | +import java.nio.ByteBuffer; |
| 5 | +import java.nio.channels.SelectionKey; |
| 6 | +import java.nio.channels.Selector; |
| 7 | +import java.nio.channels.ServerSocketChannel; |
| 8 | +import java.nio.channels.SocketChannel; |
| 9 | +import java.util.Iterator; |
| 10 | +import java.util.Set; |
| 11 | + |
| 12 | +/** |
| 13 | + * @author LuoHaiYang |
| 14 | + */ |
| 15 | +public class NIOServer { |
| 16 | + |
| 17 | + public static void main(String[] args) throws Exception { |
| 18 | + |
| 19 | + // 创建ServerSocketChannel -> ServerSocket |
| 20 | + ServerSocketChannel serverSocketChannel = ServerSocketChannel.open(); |
| 21 | + |
| 22 | + // 得到一个Selector对象 |
| 23 | + Selector selector = Selector.open(); |
| 24 | + |
| 25 | + // 绑定一个端口:6666,在服务端监听 |
| 26 | + serverSocketChannel.socket().bind(new InetSocketAddress(6666)); |
| 27 | + |
| 28 | + // 设置为非阻塞 |
| 29 | + serverSocketChannel.configureBlocking(false); |
| 30 | + |
| 31 | + // 把ServerSocketChannel注册到selector, 事件为:OP_ACCEPT |
| 32 | + SelectionKey registerSelectionKey = serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT); |
| 33 | + System.out.println("Register to selector, selectionKey is OP_ACCEPT, return selectionKey = " + registerSelectionKey + ", 注册后selectionKey 数量 = " + selector.keys().size()); |
| 34 | + |
| 35 | + // 循环等待客户端连接 |
| 36 | + while (true) { |
| 37 | + // 这里我们等待1秒, 如果没有事件发生,返回 |
| 38 | + if (selector.select(1000) == 0) { |
| 39 | + // 没有事件发生 |
| 40 | + System.out.println("服务器等待了1秒,无连接"); |
| 41 | + continue; |
| 42 | + } |
| 43 | + |
| 44 | + // 如果返回结果 > 0, 就获取到相关的selectionKey集合 |
| 45 | + // 1. 如果返回 > 0,表示已经获取到关注的事件 |
| 46 | + // 2. selector.selectedKeys() 返回关注事件的集合 |
| 47 | + // 通过selectionKeys反向获取通道 |
| 48 | + Set<SelectionKey> selectionKeys = selector.selectedKeys(); |
| 49 | + |
| 50 | + // 通过迭代器遍历Set<SelectionKey> |
| 51 | + Iterator<SelectionKey> keyIterator = selectionKeys.iterator(); |
| 52 | + |
| 53 | + while (keyIterator.hasNext()) { |
| 54 | + // 获取Selectionkey |
| 55 | + SelectionKey key = keyIterator.next(); |
| 56 | + // 根据key对应的通道发生的事件做响应处理 |
| 57 | + if (key.isAcceptable()) { |
| 58 | + // 如果key是OP_ACCEPT,有新的客户端连接 |
| 59 | + // 通过ServerSocketChannel生成一个socketChannel |
| 60 | + SocketChannel socketChannel = serverSocketChannel.accept(); |
| 61 | + |
| 62 | + System.out.println("Register to selector, selectionKey is OP_ACCEPT, return selectionKey = " + registerSelectionKey + ", 注册后selectionKey 数量 = " + selector.keys().size()); |
| 63 | + |
| 64 | + // 将SocketChannel设置为非阻塞 |
| 65 | + socketChannel.configureBlocking(false); |
| 66 | + |
| 67 | + // 将socketChannel注册到selector,关注事件为OP_READ,同时给socketChannel关联一个buffer |
| 68 | + socketChannel.register(selector, SelectionKey.OP_READ, ByteBuffer.allocate(1024)); |
| 69 | + |
| 70 | + } |
| 71 | + |
| 72 | + System.out.println("isReadable = " + key.isReadable() + ", isWritable = " + key.isWritable() + ", isValid = " + key.isValid()); |
| 73 | + |
| 74 | + if (key.isReadable()) { |
| 75 | + // 如果key是OP_READ |
| 76 | + // 通过key反向获取到对应channel |
| 77 | + SocketChannel channel = (SocketChannel) key.channel(); |
| 78 | + |
| 79 | + // 获取该channel关联的buffer |
| 80 | + ByteBuffer buffer = (ByteBuffer)key.attachment(); |
| 81 | + |
| 82 | + // 从buffer中读取数据到channel中 |
| 83 | + channel.read(buffer); |
| 84 | + |
| 85 | + System.out.println("from 客户端 " + new String(buffer.array())); |
| 86 | + } |
| 87 | + |
| 88 | + // 手动从集合中移动当前的selectionKey,防止重复操作 |
| 89 | + keyIterator.remove(); |
| 90 | + } |
| 91 | + |
| 92 | + } |
| 93 | + } |
| 94 | +} |
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