网络编程的基本模型是Client/Server模型。也就是两个进程之间进行相互通信，当中服务端提供位置信息（
绑定ip地址和监听port），client通过连接操作向服务端监听的地址发送连接请求，通过三次握手建立连接。
假设连接成功。两方就能够通过socket进行通信。
在基于传统的同步堵塞模型开发中。ServerSocket负责绑定IP地址，启动监听port：Socket负责发起连接请求
操作。操作连接成功后，两方通过输入和输出流进行同步堵塞通信。
以下是经典的时间server代码,分析工作过程：
TimeServer代码：
package com.panther.dong.netty.bio.synchronousblockio;
import java.net.ServerSocket;
import java.net.Socket;
/**
* server thread(corresponding to all client thread)
* Created by panther on 15-8-11.
*/
public class TimeServer {
public static void main(String[] args) {
int port = 8080;
if (args != null && args.length > 0) {
port = Integer.valueOf(args[0]);
}
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();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (server != null) {
System.out.println("the time server close");
try {
server.close();
} catch (Exception e) {
}
server = null;
}
}
}
}
TimerServer依据传入參数设置监听的port。假设没有入參，使用默认8080port。通过构造函数创建ServerSocket
。假设port合法且没有被占用。服务端监听成功。
程序中通过一个循环来监听client的接入，假设没有client的
接入，则线程堵塞在ServerSocket的accept操作上。启动TimeServer，等待client的接入
TimeServerHandler的代码：
package com.panther.dong.netty.bio.synchronousblockio;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Date;
/**
* listener client socket
* Created by panther on 15-8-11.
*/
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 current = null;
String body = null;
while (true) {
body = in.readLine();
if (body == null) {
break;
}
System.out.println("The time server receive order : " + body);
current = "QUERY TIME ORDER".equalsIgnoreCase(body) ?
new Date(System.currentTimeMillis()).toString() :
"BAD ORDER";
out.println(current);
}
} catch (Exception e) {
if (in != null) {
try {
in.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
if (out != null) {
out.close();
out = null;
}
if (this.socket != null) {
try {
this.socket.close();
} catch (IOException e1) {
e1.printStackTrace();
}
this.socket = null;
}
}
}
}
client代码TimeClient：
package com.panther.dong.netty.bio.synchronousblockio;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
/**
* client thread(one thread)
* Created by panther on 15-8-13.
*/
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) {
}
}
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 (IOException e) {
} finally {
if (out != null) {
out.close();
out = null;
}
if (in != null) {
try {
in.close();
} catch (IOException e) {
}
in = null;
}
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
}
socket = null;
}
}
}
}
执行结果：
先执行TimeServer得到结果：
在执行TimeClient。得到例如以下结果：
由上面的图可知道。TimeServer和TimeClient建立连接！
！
！！
BIO的弊端：
每当一个新的client接入请求时，server必须创建一个新的线程处理新接入的链路。一个线程仅仅能处理一个
client的连接。在高性能server的应用领域，往往须要成千上万个client的并发连接。这样的模型无法满足高性能
、高并发接入的场景。！
。。
BIO介绍完成~~~~~~~