同步阻塞模式

利用长轮询实现持续监听，利用socketserver.accept()进行阻塞。
在一个由volatile变量控制的while循环中，不断尝试serversocket.accept()方法，当没有socket进行连接时，程序会阻塞在该方法>上，当有socket连接时，则获得这个socket，传递给工作线程池，并继续等待。这种方式在处理高并发情况下会创建过多的socket连接，导致消耗大量内存。

服务端代码

public class ServerStarterextends Thread {
    private static volatile boolean flag =true;
    private ServerSocketserverSocket =null;
    private ExecutorServiceserverThreadPool;
    ServerStarter( int port) {
        ThreadFactory threadFactory =new ThreadFactoryBuilder()
.setNameFormat("server-pool-%d").build();
        serverThreadPool =new ThreadPoolExecutor(10, 10,
                1000, TimeUnit.MILLISECONDS,
                new LinkedBlockingQueue(1024), threadFactory, new ThreadPoolExecutor.AbortPolicy());
        try {
serverSocket =new ServerSocket(port);
        }catch (IOException e) {
e.printStackTrace();
        }
}

@Override
    public void run() {
while (flag) {
try {
Socket sock =serverSocket.accept();
                SocketTask s =new SocketTask(sock);
                serverThreadPool.submit(s);
            }catch (IOException e) {
System.out.println("system shutdown");
            }
}
}

在创建线程池时，推荐使用阿里编程规约中推荐的利用线程池构造器来进行构造，这种方式可以对线程池的线程进行命名，便于日后的调试与维护。
这里这我们创建了一个线程池来独立处理每一个socket连接，从而实现了对多客户端同时访问的支持，下面是任务线程类示范

 public void client() {
        try {
            Socket socket = new Socket(serverhost, serverport);
            dojob();
            writer = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
            writer.write(msg);
            writer.newLine();
            writer.flush();
            try {
                /**获取一个输入流，接收服务端的信息*/
                InputStream inputStream = socket.getInputStream();
                /**包装成字符流，提高效率*/
                InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
                /**缓冲区*/
                BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
                String t = bufferedReader.readLine();
                dosomething();
            } catch (Exception e) {
                System.out.println("server send wrong data");
            }
            socket.close();
        } catch (UnknownHostException e) {
            System.out.println("host not found");
        } catch (IOException e) {
            System.out.println("server holding");
        }
    }