Nginx_BIO_NIO_AIO面试题（2021最新版）

package com.test.io;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
//TCP协议Socket使用BIO进行通信：服务端
public class BIOServer {
// 在main线程中执行下面这些代码
public static void main(String[] args) {
//使用Socket进行网络通信
ServerSocket server = null;
Socket socket = null;
//基于字节流
InputStream in = null;
OutputStream out = null;
try {
server = new ServerSocket(8000);
System.out.println("服务端启动成功，监听端口为8000，等待客户端连接...");
while (true){
socket = server.accept(); //等待客户端连接
System.out.println("客户连接成功，客户信息为：" +
socket.getRemoteSocketAddress());
in = socket.getInputStream();
byte[] buffer = new byte[1024];
int len = 0;
//读取客户端的数据
while ((len = in.read(buffer)) > 0) {
System.out.println(new String(buffer, 0, len));
}
//向客户端写数据
out = socket.getOutputStream();
out.write("hello!".getBytes());
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
TCP协议Socket使用BIO进行通信：客户端（第二执行）
package com.test.io;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Scanner;
//TCP协议Socket使用BIO进行通信：客户端
public class Client01 {
public static void main(String[] args) throws IOException {
//创建套接字对象socket并封装ip与port
Socket socket = new Socket("127.0.0.1", 8000);
//根据创建的socket对象获得一个输出流
//基于字节流
OutputStream outputStream = socket.getOutputStream();
//控制台输入以IO的形式发送到服务器
System.out.println("TCP连接成功 \n请输入：");
String str = new Scanner(System.in).nextLine();
byte[] car = str.getBytes();
outputStream.write(car);
System.out.println("TCP协议的Socket发送成功");
//刷新缓冲区
outputStream.flush();
//关闭连接
socket.close();
}
}
package com.test.io;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Scanner;
//TCP协议Socket：客户端
public class Client02 {
public static void main(String[] args) throws IOException {
//创建套接字对象socket并封装ip与port
Socket socket = new Socket("127.0.0.1", 8000);
//根据创建的socket对象获得一个输出流
//基于字节流
OutputStream outputStream = socket.getOutputStream();
//控制台输入以IO的形式发送到服务器
System.out.println("TCP连接成功 \n请输入：");
String str = new Scanner(System.in).nextLine();
byte[] car = str.getBytes();
outputStream.write(car);
System.out.println("TCP协议的Socket发送成功");
//刷新缓冲区
outputStream.flush();
//关闭连接
socket.close();
}
}

package com.test.io;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
//TCP协议Socket使用多线程BIO进行通行：服务端
public class BIOThreadService {
public static void main(String[] args) {
try {
ServerSocket server = new ServerSocket(8000);
System.out.println("服务端启动成功，监听端口为8000，等待客户端连接... ");
while (true) {
Socket socket = server.accept();//等待客户连接
System.out.println("客户连接成功，客户信息为：" +
socket.getRemoteSocketAddress());
//针对每个连接创建一个线程， 去处理I0操作
//创建多线程创建开始
Thread thread = new Thread(new Runnable() {
public void run() {
try {
InputStream in = socket.getInputStream();
byte[] buffer = new byte[1024];
int len = 0;
//读取客户端的数据
while ((len = in.read(buffer)) > 0) {
System.out.println(new String(buffer, 0, len));
}
//向客户端写数据
OutputStream out = socket.getOutputStream();
out.write("hello".getBytes());
} catch (IOException e) {
e.printStackTrace();
}
}
});
thread.start();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}

package com.test.io;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
//TCP协议Socket使用线程池BIO进行通行：服务端
public class BIOThreadPoolService {
	public static void main(String[] args) {
		//创建线程池
		ExecutorService executorService = Executors.newFixedThreadPool(30);
		try {
			ServerSocket server = new ServerSocket(8000);
			System.out.println("服务端启动成功，监听端口为8000，等待客户端连接...");
			while (true) {
				Socket socket = server.accept();
				//等待客户连接
				System.out.println("客户连接成功，客户信息为：" +
				socket.getRemoteSocketAddress());
				//使用线程池中的线程去执行每个对应的任务
				executorService.execute(new Thread(new Runnable() {
					public void run() {
						try {
							InputStream in = socket.getInputStream();
							byte[] buffer = new byte[1024];
							int len = 0;
							//读取客户端的数据
							while ((len = in.read(buffer)) > 0) {
								System.out.println(new String(buffer, 0, len));
							}
							//向客户端写数据
							OutputStream out = socket.getOutputStream();
							out.write("hello".getBytes());
						}
						catch (IOException e) {
							e.printStackTrace();
						}
					}
				}
				)
				);
			}
		}
		catch (IOException e) {
			e.printStackTrace();
		}
	}
}

package com.test.io;
import com.lijie.iob.RequestHandler;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Set;
public class NIOServer {
	public static void main(String[] args) throws IOException {
		//111111111
		//Service端的Channel，监听端口的
		ServerSocketChannel serverChannel = ServerSocketChannel.open();
		//设置为非阻塞
		serverChannel.configureBlocking(false);
		//nio的api规定这样赋值端口
		serverChannel.bind(new InetSocketAddress(8000));
		//显示Channel是否已经启动成功，包括绑定在哪个地址上
		System.out.println("服务端启动成功，监听端口为8000，等待客户端连接..."+
		serverChannel.getLocalAddress());
		//22222222
		//声明selector选择器
		Selector selector = Selector.open();
		//这句话的含义，是把selector注册到Channel上面，
		//每个客户端来了之后，就把客户端注册到Selector选择器上,默认状态是Accepted
		serverChannel.register(selector, SelectionKey.OP_ACCEPT);
		//33333333
		//创建buffer缓冲区，声明大小是1024，底层使用数组来实现的
		ByteBuffer buffer = ByteBuffer.allocate(1024);
		RequestHandler requestHandler = new RequestHandler();
		//444444444
		//轮询，服务端不断轮询，等待客户端的连接
		//如果有客户端轮询上来就取出对应的Channel，没有就一直轮询
		while (true) {
			int select = selector.select();
			if (select == 0) {
				continue;
			}
			//有可能有很多，使用Set保存Channel
			Set<SelectionKey> selectionKeys = selector.selectedKeys();
			Iterator<SelectionKey> iterator = selectionKeys.iterator();
			while (iterator.hasNext()) {
				//使用SelectionKey来获取连接了客户端和服务端的Channel
				SelectionKey key = iterator.next();
				//判断SelectionKey中的Channel状态如何，如果是OP_ACCEPT就进入
				if (key.isAcceptable()) {
					//从判断SelectionKey中取出Channel
					ServerSocketChannel channel = (ServerSocketChannel)
					key.channel();
					//拿到对应客户端的Channel
					SocketChannel clientChannel = channel.accept();
					//把客户端的Channel打印出来
					System.out.println("客户端通道信息打印：" + clientChannel.getRemoteAddress());
					//设置客户端的Channel设置为非阻塞
					clientChannel.configureBlocking(false);
					//操作完了改变SelectionKey中的Channel的状态OP_READ
					clientChannel.register(selector, SelectionKey.OP_READ);
				}
				//到此轮训到的时候，发现状态是read，开始进行数据交互
				if (key.isReadable()) {
					//以buffer作为数据桥梁
					SocketChannel channel = (SocketChannel) key.channel();
					//数据要想读要先写，必须先读取到buffer里面进行操作
					channel.read(buffer);
					//进行读取
					String request = new String(buffer.array()).trim();
					buffer.clear();
					//进行打印buffer中的数据
					System.out.println(String.format("客户端发来的消息： %s : %s",
					channel.getRemoteAddress(), request));
					//要返回数据的话也要先返回buffer里面进行返回
					String response = requestHandler.handle(request);
					//然后返回出去
					channel.write(ByteBuffer.wrap(response.getBytes()));
				}
				iterator.remove();
			}
		}
	}
}

package com.test.io;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Scanner;
//TCP协议Socket：客户端
public class Client01 {
	public static void main(String[] args) throws IOException {
		//创建套接字对象socket并封装ip与port
		Socket socket = new Socket("127.0.0.1", 8000);
		//根据创建的socket对象获得一个输出流
		OutputStream outputStream = socket.getOutputStream();
		//控制台输入以IO的形式发送到服务器
		System.out.println("TCP连接成功 n请输入：");
		while(true){
			byte[] car = new Scanner(System.in).nextLine().getBytes();
			outputStream.write(car);
			System.out.println("TCP协议的Socket发送成功");
			//刷新缓冲区
			outputStream.flush();
		}
	}
}