socket nio 多线程接收客户端信息

来源：互联网发布：垃圾对人类的危害数据编辑：程序博客网时间：2024/05/22 11:03
在连接数很大的情况下，使用Selector能减少并发线程数，减少上下文切换的消耗，非阻塞IO使得具备流程的读写。
package main; import java.io.IOException;import java.net.InetSocketAddress;import java.net.ServerSocket;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.nio.charset.Charset;import java.util.Iterator;import java.util.Set;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors; public class Server {    private final int PORT = 1234;    private ExecutorService pool;    private ServerSocketChannel ssc;    private Selector selector;    private static Charset charset = Charset.forName("utf-8");    private int n;         public static void main(String[] args) throws IOException{        Server server = new Server();        server.doService();    }         public Server() throws IOException{        pool = Executors.newFixedThreadPool(5);                 ssc = ServerSocketChannel.open();        ssc.configureBlocking(false);        ServerSocket ss = ssc.socket();        ss.bind(new InetSocketAddress(PORT));        selector = Selector.open();        ssc.register(selector,SelectionKey.OP_ACCEPT);        System.out.println("Server started...");    }         public void doService(){        while(true){            try{                n = selector.select();            }catch (IOException e) {                throw new RuntimeException("Selector.select()异常!");            }            if(n==0)                continue;            Set<SelectionKey> keys = selector.selectedKeys();            Iterator<SelectionKey> iter = keys.iterator();            while(iter.hasNext()){                SelectionKey key = iter.next();                iter.remove();                if(key.isAcceptable()){                    SocketChannel sc = null;                    try{                        sc = ((ServerSocketChannel)key.channel()).accept();                        sc.configureBlocking(false);                        System.out.println("客户端:"+sc.socket().getInetAddress().getHostAddress()+" 已连接");                        SelectionKey k = sc.register(selector, SelectionKey.OP_READ);                        ByteBuffer buf = ByteBuffer.allocate(1024);                        k.attach(buf);                    }catch (Exception e) {                        try{                            sc.close();                        }catch (Exception ex) {                        }                    }                }                else if(key.isReadable()){                    key.interestOps(key.interestOps()&(~SelectionKey.OP_READ));                    pool.execute(new Worker(key));                }            }        }    }         public static class Worker implements Runnable{        private SelectionKey key;        public Worker(SelectionKey key){            this.key = key;        }                 @Override        public void run() {            SocketChannel sc = (SocketChannel)key.channel();            ByteBuffer buf = (ByteBuffer)key.attachment();            buf.clear();            int len = 0;            try{                while((len=sc.read(buf))>0){//非阻塞，立刻读取缓冲区可用字节                    buf.flip();                    System.out.println("客户端："+charset.decode(buf).toString());                    buf.clear();                }                if(len==-1){                    System.out.println("客户端断开。。。");                    sc.close();                }                //没有可用字节,继续监听OP_READ                key.interestOps(key.interestOps()|SelectionKey.OP_READ);                key.selector().wakeup();            }catch (Exception e) {                try {                    sc.close();                } catch (IOException e1) {                }            }        }    }}
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