同步阻塞式I/O编程

来源：互联网发布：cs软件界面设计工具编辑：程序博客网时间：2024/06/08 17:12

1.BIO主要的问题在于每当有一个新的客户端请求接入时，服务器必须创建一个新的线程处理新接入的客户端链路，一个线程只可以处理一个客户端连接，在高性能服务器应用领域，往往需要面向成千上万个客户端的并发连接，这种模型显然无法满足高性能，高并发接入的场合
代码例子：
1.server端代码

package com.afan.bio;import java.io.IOException;import java.net.ServerSocket;import java.net.Socket;/** * 同步阻塞io * @author Lenovo * */public class TimeServer {    public static void main(String[] args) throws IOException{        int port = 8080;        if(args != null && args.length > 0){            try {                port = Integer.valueOf(args[0]);            } catch (NumberFormatException e) {                // 采用默认值            }        }        ServerSocket server = null;        try {            server = new ServerSocket(port);            System.out.println("the time server is start in port：" + port);            Socket socket = null;            while (true) {                socket = server.accept();                new Thread(new TimeServerHandler(socket)).start();            }        } finally{            if(server != null){                System.out.println("the time server close");                server.close();                server = null;            }        }    }}

2.server端处理类

package com.afan.bio;import java.io.BufferedReader;import java.io.InputStreamReader;import java.io.PrintWriter;import java.net.Socket;import java.sql.Date;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(this.socket.getInputStream()));            out = new PrintWriter(this.socket.getOutputStream(),true);            String currentTime = null;            String body = null;            while(true){                body = in.readLine();                if(body == null){                    break;                }                System.out.println("the time server receive order :" + body);                currentTime = "Query TIME ORDER".equals(body) ? new Date(System.currentTimeMillis()).toString()                        :"BAD ORDER";                out.println(currentTime);            }        } catch (Exception e) {            if(in != null){                try {                    in.close();                } catch (Exception e2) {                    e2.printStackTrace();                }            }            if(out != null){                out.close();                out = null;            }            if(this.socket != null){                try {                    this.socket.close();                } catch (Exception e2) {                    e2.printStackTrace();                }                this.socket = null;            }        }    }}

3.客户端代码

package com.afan.bio;import java.io.BufferedReader;import java.io.InputStreamReader;import java.io.PrintWriter;import java.net.Socket;public class TimeClient {    public static void main(String[] args){        int port = 8080;        if(args != null && args.length > 0){            try {                port = Integer.valueOf(args[0]);            } catch (Exception e) {                //采用默认值            }        }        Socket socket = null;        BufferedReader in = null;        PrintWriter out = null;        try {            socket = new Socket("127.0.0.1",port);            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));            out = new PrintWriter(socket.getOutputStream(),true);            out.println("QUERY TIME ORDER");            System.out.println("send order 2 server succeed.");            String resp = in.readLine();            System.out.println("NOW IS :"+ resp);        } catch (Exception e) {            // 不需要处理        }finally{            if(in != null){                try {                    in.close();                } catch (Exception e2) {                    e2.printStackTrace();                }            }            if(out != null){                out.close();                out = null;            }            if(socket != null){                try {                    socket.close();                } catch (Exception e2) {                    e2.printStackTrace();                }                socket = null;            }        }    }}

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