BIO编程及其特点分析

秒速五厘米 2022-09-11 05:24 106阅读 0赞

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。