[网络协议]BIO编程及其特点分析

服务端：

监听端口，监听客户端发送的消息，返回服务器时间给客户端。

package com.tech.netty.bio;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * @author lw
 * @since 2021/9/13
 */
public class BioServer {

    private static final int PORT = 8080;

    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = null;
        try {
            serverSocket = new ServerSocket(PORT);
            System.out.println("the time server is start in port :" + PORT);
            Socket socket = null;
            while (true) {
                socket = serverSocket.accept();
                new Thread(new TimeServerHandler(socket)).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (serverSocket != null) {
                System.out.println("the time server close");
                serverSocket.close();
            }
        }
    }


}

package com.tech.netty.bio;

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

/**
 * @author lw
 * @since 2021/9/13
 */
public class TimeServerHandler implements Runnable {

    private Socket socket;

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

    @Override
    public void run() {
        BufferedReader in=null;
        PrintWriter out=null;
        try{
            in=new BufferedReader(new InputStreamReader(socket.getInputStream()));
            out=new PrintWriter(socket.getOutputStream(),true);
            String body;
            while((body=in.readLine())!=null && body.length()!=0){
                System.out.println("the time server receive msg :"+body);
                out.println(new Date().toString());
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if(in != null){
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(out!=null){
                try {
                    out.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            if(this.socket!=null){
                try {
                    this.socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

客户端：

连接服务器，发送消息给服务器，打印服务器返回的消息。

package com.tech.netty.bio;

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

/**
 * @author lw
 * @since 2021/9/13
 */
public class BioClient {
    private static final String HOST = "127.0.0.1";
    private static final int PORT = 8080;

    public static void main(String[] args) {
        Socket socket = null;
        BufferedReader in = null;
        PrintWriter out = null;
        try {
            socket = new Socket(HOST, PORT);
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            out = new PrintWriter(socket.getOutputStream(),true);
            out.println("i am client");
            String resp = in.readLine();
            System.out.println("当前服务器时间是:" + resp);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (out != null) {
                try {
                    out.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            if (socket != null) {
                try {
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

特点分析：

? ? ? ? 优点：模型和编程简单。

? ? ? ? 缺点：一个线程处理一个连接，在高并发场景下，CPU切换线程上下文资源消耗大。

? ? ? ? tomcat7之前的版本采用BIO，之后的版本采用NIO。

? ? ? ? 可以使用线程池，改进BIO。