声明

该系列文章由书籍《Netty权威指南》第二版整理而来。只为记录学习笔记。
若认为内容侵权请及时通知本人删除相关内容。

[TOC]

时间服务器--升级版(线程池)的BIO

服务端代码

服务端主程序

public class TimeServer {

    public static void main(String[] args) {
        int port = 1234;
        ServerSocket server = null;
        try {
            server = new ServerSocket(port);
            System.out.println("The time server is listening in port : " + port);
            Socket socket = null;
            // 线程池
            ClientHandlerPool singleExecutor = new ClientHandlerPool(50, 10000);
            while (true) {
                socket = server.accept();
                singleExecutor.execute(new TimeServerHandler(socket));
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (server != null) {
                try {
                    server.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

服务端线程池

public class ClientHandlerPool {

    private ExecutorService executor;

    public ClientHandlerPool(int maxPoolSize, int queueSize) {
        executor = new ThreadPoolExecutor(Runtime.getRuntime().availableProcessors(), maxPoolSize, 120L,
                TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(queueSize));
    }

    public void execute(Runnable task) {
        executor.execute(task);
    }
}

服务端处理器类

public class TimeServerHandler implements Runnable {

    private Socket socket;
    private SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    public TimeServerHandler(Socket socket) {
        this.socket = socket;
    }

    @Override
    public void run() {
        BufferedReader in = null;
        PrintWriter out = null;
        try {
            in = new BufferedReader(new InputStreamReader(this.socket.getInputStream()));
            out = new PrintWriter(this.socket.getOutputStream(), true);
            String body = null;
            while (true) {
                body = in.readLine();
                if (body == null)
                    break;
                out.println(this.sdf.format(new Date()));
            }

        } catch (Exception e) {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
            if (out != null) {
                out.close();
                out = null;
            }
            if (this.socket != null) {
                try {
                    this.socket.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
        }
    }
}

客户端代码

客户端代码和上一篇文章“传统BIO”一致。

总结

这种升级版BIO模型有如下特点:

• 服务端资源开销可控
• 当服务端队列积满后，新的连接必须排队
• 可能导致所有的新的连接都超时

参考资料: 《Netty权威指南》第二版