BIO:同步阻塞式程式設計,同一個線程隻能處理一個用戶端請求。
代碼實作如下(本地可以通過Telnet充當用戶端+debug斷點測試功能):
package io;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.charset.StandardCharsets;
/**
* 阻塞IO
*/
public class BioServerDemo {
public static void main(String[] args) throws IOException {
ServerSocket serverSocket = new ServerSocket(9000);
while(true){
System.out.println("等待連接配接。。");
// 阻塞方法
// telnet localhost 9000
// CTRL+]進入Telnet指令
Socket clientSocket = serverSocket.accept();
System.out.println("有用戶端連接配接了。。");
// 雖然采用多線程可以支援多個線程同時通路,但是會引發C10K問題
// new Thread(new Runnable() {
// @Override
// public void run() {
// try {
handler(clientSocket);
// } catch (IOException e) {
// e.printStackTrace();
// }
// }
// }).start();
}
}
private static void handler(Socket clientSocket) throws IOException {
byte[] bytes = new byte[1024];
System.out.println("準備read。。");
// 接收用戶端的資料,阻塞方法,沒有資料可讀時就阻塞
int read = clientSocket.getInputStream().read(bytes);
System.out.println("read完畢。。");
if (read !=-1){
System.out.println("接收用戶端的資料:"+new String(bytes,0,read));
}
// clientSocket.getOutputStream().write("HelloClint".getBytes(StandardCharsets.UTF_8));
// clientSocket.getOutputStream().flush();
}
}
telnet指令(建議開兩個看效果):telnet localhost 9000(連接配接後CTRL+]進入Telnet指令)
控制台輸出:
NIO:同步非阻塞,同一個線程可以處理多個用戶端請求。
代碼實作:
package io;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.nio.ByteBuffer;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
*初版- NIO(非阻塞)程式設計
*/
public class NioServer {
static List<SocketChannel> channelList = new ArrayList<>();
public static void main(String[] args) throws IOException {
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.socket().bind(new InetSocketAddress(9000));
serverSocketChannel.configureBlocking(false);
System.out.println("服務啟動成功");
while (true){
SocketChannel socketChannel = serverSocketChannel.accept();
if(socketChannel!=null){
System.out.println("連接配接成功");
socketChannel.configureBlocking(false);
channelList.add(socketChannel);
}
// 問題點: 空循環時間耗時太久
Iterator<SocketChannel> iterator = channelList.iterator();
while (iterator.hasNext()){
SocketChannel sc = iterator.next();
ByteBuffer byteBuffer = ByteBuffer.allocate(128);
int len = sc.read(byteBuffer);
if (len>0){
System.out.println("接收到消息:"+new String(byteBuffer.array()));
}else if(len ==-1){
iterator.remove();
System.out.println("用戶端斷開連接配接");
}
}
}
}
}
package io;
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;
/**
*進階版- NIO(非阻塞)程式設計
* 這是netty和Redis的雛形
*/
public class NioSelectorServer {
public static void main(String[] args) throws IOException {
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.socket().bind(new InetSocketAddress(9000));
serverSocketChannel.configureBlocking(false);
// 啟用epoll模型
Selector selector = Selector.open();
// 注冊阻塞事件:建立連接配接
SelectionKey selectionKey = serverSocketChannel.register(selector,SelectionKey.OP_ACCEPT);
System.out.println("服務啟動成功");
while (true){
// 阻塞等待需要處理的事件發生,這個時候是等待連接配接
selector.select();
// 擷取阻塞的事件
Set<SelectionKey> selectionKeys = selector.selectedKeys();
// 對阻塞事件進行周遊
Iterator<SelectionKey> iterator = selectionKeys.iterator();
if(iterator.hasNext()){
SelectionKey key =iterator.next();
if(key.isAcceptable()){//連接配接已建立
ServerSocketChannel server = (ServerSocketChannel) key.channel();
SocketChannel socketChannel = server.accept();
socketChannel.configureBlocking(false);
// 注冊阻塞事件:讀取資料
SelectionKey selKey = socketChannel.register(selector,SelectionKey.OP_READ);
}else if(key.isReadable()){//這裡隻針對read事件,有需要可以針對write事件處理
SocketChannel socketChannel = (SocketChannel) key.channel();
ByteBuffer byteBuffer = ByteBuffer.allocate(128);
socketChannel.configureBlocking(false);
int len = socketChannel.read(byteBuffer);
if(len >0 ){
System.out.println("接收到消息:"+new String(byteBuffer.array()));
}else if(len ==-1 ){
// 關閉socket
socketChannel.close();
System.out.println("接收完成");
}
}
// 把處理完的阻塞事件移除
iterator.remove();
}
}
}
}
Telnet如圖:
控制台輸出:
netty:可以了解成在NIO的selector版本上進行了封裝
代碼實作:
package io.netty;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
/**
* netty 服務端
*/
public class NettyServer {
public static void main(String[] args) {
// 我們要建立兩個EventLoopGroup,
// 一個是boss專門用來接收連接配接,可以了解為處理accept事件,
// 另一個是worker,可以關注除了accept之外的其它事件,處理子任務。
//上面注意,boss線程一般設定一個線程,設定多個也隻會用到一個,而且多個目前沒有應用場景,
// worker線程通常要根據伺服器調優,如果不寫預設就是cpu的兩倍。
//boss注冊accept事件
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
// worker注冊其他事件
EventLoopGroup workerGroup = new NioEventLoopGroup(8);
//服務端要啟動,需要建立ServerBootStrap,
// 在這裡面netty把nio的模闆式的代碼都給封裝好了
ServerBootstrap bootstrap = new ServerBootstrap();
try {
//配置boss和worker線程
bootstrap.group(bossGroup,workerGroup)
//配置Server的通道,相當于NIO中的ServerSocketChannel
.channel(NioServerSocketChannel.class)
//初始化伺服器連接配接隊列大小,服務端處理用戶端連接配接請求是順利處理的,是以同一個事件隻能處理一個用戶端連接配接。
// 多個用戶端同時來的時候,服務端将不能處理的用戶端連接配接請求放在隊列中等待處理。
.option(ChannelOption.SO_BACKLOG,1024)
//childHandler表示給worker那些線程配置了一個處理器,
// 配置初始化channel,也就是給worker線程配置對應的handler,當收到用戶端的請求時,配置設定給指定的handler處理
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new NettyServerHandler());//添加handler,也就是具體的IO事件處理器
}
});
System.out.println("netty server start ..");
//由于預設情況下是NIO異步非阻塞,是以綁定端口後,通過sync()方法阻塞直到連接配接建立
//綁定端口并同步等待用戶端連接配接(sync方法會阻塞,直到整個啟動過程完成)
ChannelFuture cf = bootstrap.bind(9000).sync();
//等待服務端監聽端口關閉
cf.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}finally {
//釋放線程資源
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
package io.netty;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;
/**
* 服務端ChannelHandler處理類
*/
public class NettyServerHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println("用戶端連接配接通道建立完成");
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
ByteBuf buf = (ByteBuf) msg;
System.out.println("收到用戶端的消息:"+buf.toString(CharsetUtil.UTF_8));
}
}
package io.netty;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
/**
* @description:netty用戶端
* @author: zhoufanshou
* @date: 2022/8/8 14:32
**/
public class NettyClient {
public static void main(String[] args) {
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(group)
.channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new NettyClientHandler());//增加處理類
}
});
System.out.println("netty client start..");
ChannelFuture cf = bootstrap.connect("127.0.0.1",9000);
cf.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
}finally {
group.shutdownGracefully();
}
}
}
package io.netty;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.buffer.UnpooledDirectByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;
import java.nio.charset.StandardCharsets;
/**
* @description:用戶端ChannelHandler處理類
* @author: zhoufanshou
* @date: 2022/8/8 14:29
**/
public class NettyClientHandler extends ChannelInboundHandlerAdapter {
/**
* @description:
* @author: zhoufanshou
* @date: 2022/8/8 14:22
* @param: ctx
* @return:
**/
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
ByteBuf buf = Unpooled.copiedBuffer("helloworld".getBytes(StandardCharsets.UTF_8));
ctx.writeAndFlush(buf);
}
/**
* @description:
* @author: zhoufanshou
* @date: 2022/8/8 14:22
* @param: ctx, msg
* @return:
**/
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
ByteBuf buf = (ByteBuf) msg;
System.out.println("用戶端收到資訊:"+buf.toString(CharsetUtil.UTF_8));
}
}
控制台輸出:
首先設定idea用戶端多執行個體運作:
輸出結果(打開兩個用戶端的效果)如下: