Netty 快速入门系列 - Chapter 1 传统OIO与NIO - 传统OIO 【第一讲】

本文介绍了一个简单的传统IO模型实现案例，并针对其在处理多个客户端连接时存在的阻塞性问题，通过引入线程池的方式进行优化。优化后的服务器能够更高效地处理并发请求。

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Chapter1 章节结构

1. 传统IO 特点 IO阻塞

package com.john.netty.learn.ch01.oio;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.handler;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class OioServer {
  
   public OioServer(int port) {
    this.port = port;
  }
  public void start() {
    try {
      serverSocket = new ServerSocket(this.port);
      System.out.println("服务启动");
      while (true) {
        Socket socket = serverSocket.accept();
        if (socket == null) {
          continue;
        }
        System.out.println("来了一个客户");
         handler(socket); //线程堵塞
      }
    } catch (Throwable e) {
    }
  }
  private void handler(Socket socket) {
    InputStream is = null;
    OutputStream os = null;
    byte[] bytes = new byte[10];
    try {
      is = socket.getInputStream();
      int length = -1;
      while ((length = is.read(bytes)) != -1) {
        System.out.println(new String(bytes, 0, length));
      }
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      try {
        is.close();
      } catch (IOException e) {
      }
    }
  }
  private int port;
  private ServerSocket serverSocket = null;
  public static void main(String[] args) {
    new OioServer(1000).start();
  }

}

解决方法：用线程池可以有多个客户端连接，但是非常消耗性能，每一个客户都需要一个线程提供独立服务。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;


public class OioServer {


	private ExecutorService executorService = Executors.newFixedThreadPool(5);


	public OioServer(int port) {


		this.port = port;
	}


	public void start() {


		try {


			serverSocket = new ServerSocket(this.port);
			System.out.println("服务启动");


			while (true) {


				Socket socket = serverSocket.accept();


				if (socket == null) {
					continue;
				}


				System.out.println("来了一个客户");


				executorService.submit(new Runnable() {


					@Override
					public void run() {
						handler(socket);


					}
				});


			}


		} catch (Throwable e) {


			e.printStackTrace();
		}


	}


	private void handler(Socket socket) {


		InputStream is = null;
		OutputStream os = null;


		byte[] bytes = new byte[10];


		try {


			is = socket.getInputStream();


			int length = -1;


			while ((length = is.read(bytes)) != -1) {


				System.out.println(new String(bytes, 0, length));


			}


		} catch (IOException e) {


			e.printStackTrace();


		} finally {


			try {
				is.close();
			} catch (IOException e) {


			}


		}


	}


	private int port;


	private ServerSocket serverSocket = null;


	public static void main(String[] args) {


		new OioServer(1000).start();
	}



}

餐厅例子：每一个客户一个服务员，及其浪费线程。