bio模型

• 优点

模型简单 编码简单

• 缺点

性能瓶颈 请求数和线程数1:1的关系。高并发情况下，CPU切换线程上下文损耗大

• 案例

web服务器tomcat7之前都是bio，7之后使用的是bio

• 改进

使用线程池接受 socket

• bio模型

  
  bio模型

• 重点类

ServerSocket , Socket = server.accept()

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.*;

public class Server {

    public static ExecutorService executorService =
            new ThreadPoolExecutor(5, 10, 5, TimeUnit.SECONDS, new ArrayBlockingQueue<>(20));

    public static void main(String[] args) {
        ServerSocket server = null;
        try {
            ServerHandler serverHandler= new ServerHandler();

            server = new ServerSocket(8888);

            while (true){
                Socket accept = server.accept();
                executorService.execute(() -> serverHandler.run(accept));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            //一些必要的清理工作
            if(server != null){
                System.out.println("服务器已关闭。");
                try {
                    server.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Date;

public class ServerHandler {

    public void run(Socket socket) {
        BufferedReader in = null;
        PrintWriter out = null;
        try {
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            out = new PrintWriter(socket.getOutputStream(), true);

            String body = null;

            while ((body = in.readLine()) != null && body.length() != 0) {
                System.out.println("接受到的消息：" + body);
                out.println(new Date());
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (out != null) {
                out.close();
            }
        }
    }
}

import java.io.*;
import java.net.Socket;

public class Client {

    public static void main(String[] args) {
        send("1234");
    }

    public static void send(String expression){
        Socket socket = null;
        BufferedReader in = null;
        PrintWriter out = null;
        try{
            socket = new Socket( "127.0.0.1",8888);
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            out = new PrintWriter(socket.getOutputStream(),true);
            out.println(expression);
            System.out.println("___结果为：" + in.readLine());
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            //一下必要的清理工作
            if(in != null){
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(out != null){
                out.close();
            }
            if(socket != null){
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}