BIO、NIO、AIO
BIO
传统的IO方式，会在socket.accept()方法和read()方法发生阻塞。 第一次阻塞等待客户端的连接，第二次阻塞等待客户端的IO操作，这样会导致cpu一直在那等待，造成资源的浪费。 传统的socket通信方式：
client handler
package Demo4;
import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;
/**
* @Author: small_double
* @Date: 2019/9/29 下午4:14
* client 处理器
*/
public class BioClientHandler implements Runnable {
private Socket socket;
public BioClientHandler(Socket socket) {
this.socket = socket;
}
@Override
public void run() {
InputStream inputStream = null;
try {
inputStream = socket.getInputStream();
byte[] bytes = new byte[1024];
int count = 0;
while ((count = inputStream.read(bytes)) != -1) {
System.out.println("\n收到服务器端的数据：" +
new String(bytes, 0, count, "utf-8"));
System.out.print("请输入要发送的消息：");
}
} catch (IOException e) {
e.printStackTrace();
}
}
}Bio 客户端
package Demo4;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Scanner;
/**
* @Author: small_double
* @Date: 2019/9/29 下午4:11
* BIO客户端
*/
public class BioClient {
public static void main(String[] args) {
Socket socket = null;
OutputStream outputStream = null;
try {
socket = new Socket("127.0.0.1", 9090);
new Thread(new BioClientHandler(socket)).start();
outputStream = socket.getOutputStream();
Scanner scanner = new Scanner(System.in);
while (true) {
String s = scanner.nextLine();
if (s.trim().equals("bye")) {
break;
}
outputStream.write(s.getBytes());
outputStream.flush();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (outputStream != null) {
outputStream.close();
}
if (socket != null) {
socket.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}服务端
package Demo4;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
/**
* @Author: small_double
* @Date: 2019/9/29 下午4:30
*/
public class BioServer {
public BioServer() {
ServerSocket serverSocket = null;
try {
serverSocket = new ServerSocket(9090);
Executor executor = Executors.newFixedThreadPool(10);
while (true) {
Socket accept = serverSocket.accept();
System.out.println("客户端：" + accept.getRemoteSocketAddress().toString() + "来连接了");
executor.execute(new BioServerHandler(accept));
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (serverSocket != null) {
try {
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
public void start() {
}
public static void main(String[] args) {
new BioServer().start();
}
}bio server handler
package Demo4;
import demo3.Server;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* @Author: small_double
* @Date: 2019/9/29 下午4:37
* bio server handler
*/
public class BioServerHandler implements Runnable {
private Socket serverSocket;
public BioServerHandler(Socket serverSocket) {
this.serverSocket = serverSocket;
}
@Override
public void run() {
InputStream inputStream = null;
OutputStream outputStream = null;
try {
inputStream = serverSocket.getInputStream();
outputStream = serverSocket.getOutputStream();
int count=0;
String content=null;
byte[] bytes=new byte[1024];
while ((count=inputStream.read(bytes))!=-1){
String line=new String(bytes,0,count,"utf-8");
System.out.println(line);
content=line.trim().equalsIgnoreCase("SJ")?new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(new Date()): "你发的啥？";
outputStream.write(content.getBytes());
outputStream.flush();
}
} catch (IOException e) {
e.printStackTrace();
}finally {
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (outputStream != null) {
try {
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (serverSocket != null) {
try {
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}bio方式的缺点：浪费cpu资源，同步阻塞方式。
NIO
nio与bio相比解决了bio两次阻塞的问题（解阻塞）
NIO client
package niodemo;
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.SocketChannel;
import java.util.Iterator;
import java.util.Set;
public class NioClient {
private SocketChannel socketChannel;
private Selector selector;
private long timeOut=2000;
public NioClient(){
try {
socketChannel=SocketChannel.open();
socketChannel.configureBlocking(false);
selector=Selector.open();
if(socketChannel.connect(new InetSocketAddress("127.0.0.1",9090))){
socketChannel.register(selector, SelectionKey.OP_READ);
}else{
socketChannel.register(selector, SelectionKey.OP_CONNECT);
}
} catch (IOException e) {
e.printStackTrace();
}
}
public void start(){
try {
while (true){
selector.select(timeOut);
Set<SelectionKey> selectionKeys = selector.selectedKeys();
Iterator<SelectionKey> keyIterator = selectionKeys.iterator();
while (keyIterator.hasNext()){
SelectionKey selectionKey = keyIterator.next();
if(selectionKey.isValid()){
if(selectionKey.isConnectable()){
SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
if(socketChannel.finishConnect()){
socketChannel.register(selector,SelectionKey.OP_READ);
ByteBuffer byteBuffer=ByteBuffer.allocate(1024);
byteBuffer.put("你好".getBytes());
byteBuffer.flip();
socketChannel.write(byteBuffer);
}else{
System.err.println("可以尝试重试");
}
}
if(selectionKey.isReadable()){
SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
ByteBuffer buffer=ByteBuffer.allocate(1024);
socketChannel.read(buffer);
System.out.println(new String(buffer.array()));
}
}
keyIterator.remove();
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
new NioClient().start();
}
}AIO
异步非阻塞 IO
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