首先写在最前面的一点,关于netty5的用户指南,可以参照这里
![img_aec7a0273952ad636d945144c1419362.png](https://yqfile.alicdn.com/img_aec7a0273952ad636d945144c1419362.png?x-oss-process=image/resize,w_1400/format,webp)
![img_a21ca7a7e2745d4614adf495d5a7eaef.png](https://yqfile.alicdn.com/img_a21ca7a7e2745d4614adf495d5a7eaef.png?x-oss-process=image/resize,w_1400/format,webp)
![img_523e8094d552dd3ab2a8d4bb000a1cf7.png](https://yqfile.alicdn.com/img_523e8094d552dd3ab2a8d4bb000a1cf7.png?x-oss-process=image/resize,w_1400/format,webp)
Netty的hello world
![img_ef661cf5ddb04cc603466be438631fec.png](https://yqfile.alicdn.com/img_ef661cf5ddb04cc603466be438631fec.png?x-oss-process=image/resize,w_1400/format,webp)
![img_91c6721aeb986b5224a450de98be0178.png](https://yqfile.alicdn.com/img_91c6721aeb986b5224a450de98be0178.png?x-oss-process=image/resize,w_1400/format,webp)
一个经典的hello world程序有四个类,分布是Client,ClientHandler,Server,ServerHandler,下面是它们的代码
Client.java
package bhz.netty.helloworld;
import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.Unpooled;
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;
public class Client {
public static void main(String[] args) throws Exception{
EventLoopGroup group = new NioEventLoopGroup();
Bootstrap b = new Bootstrap();
b.group(group)
.channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel sc) throws Exception {
sc.pipeline().addLast(new ClientHandler());
}
});
ChannelFuture cf1 = b.connect("127.0.0.1", 8765).sync();
//ChannelFuture cf2 = b.connect("127.0.0.1", 8764).sync();
//发送消息
Thread.sleep(1000);
cf1.channel().writeAndFlush(Unpooled.copiedBuffer("777".getBytes()));
cf1.channel().writeAndFlush(Unpooled.copiedBuffer("666".getBytes()));
//cf2.channel().writeAndFlush(Unpooled.copiedBuffer("888".getBytes()));
Thread.sleep(2000);
cf1.channel().writeAndFlush(Unpooled.copiedBuffer("888".getBytes()));
//cf2.channel().writeAndFlush(Unpooled.copiedBuffer("666".getBytes()));
cf1.channel().closeFuture().sync();
//cf2.channel().closeFuture().sync();
group.shutdownGracefully();
}
}
ClientHandler.java
package bhz.netty.helloworld;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPromise;
import io.netty.util.ReferenceCountUtil;
public class ClientHandler extends ChannelHandlerAdapter{
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
try {
ByteBuf buf = (ByteBuf) msg;
byte[] req = new byte[buf.readableBytes()];
buf.readBytes(req);
String body = new String(req, "utf-8");
System.out.println("Client :" + body );
String response = "收到服务器端的返回信息:" + body;
} finally {
ReferenceCountUtil.release(msg);
}
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
ctx.close();
}
}
Server.java
package bhz.netty.helloworld;
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;
public class Server {
public static void main(String[] args) throws Exception {
//1 创建线两个程组
//一个是用于处理服务器端接收客户端连接的
//一个是进行网络通信的(网络读写的)
EventLoopGroup pGroup = new NioEventLoopGroup();
EventLoopGroup cGroup = new NioEventLoopGroup();
//2 创建辅助工具类,用于服务器通道的一系列配置
ServerBootstrap b = new ServerBootstrap();
b.group(pGroup, cGroup) //绑定俩个线程组
.channel(NioServerSocketChannel.class) //指定NIO的模式
.option(ChannelOption.SO_BACKLOG, 1024) //设置tcp缓冲区
.option(ChannelOption.SO_SNDBUF, 32*1024) //设置发送缓冲大小
.option(ChannelOption.SO_RCVBUF, 32*1024) //这是接收缓冲大小
.option(ChannelOption.SO_KEEPALIVE, true) //保持连接
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel sc) throws Exception {
//3 在这里配置具体数据接收方法的处理
sc.pipeline().addLast(new ServerHandler());
}
});
//4 进行绑定
ChannelFuture cf1 = b.bind(8765).sync();
//ChannelFuture cf2 = b.bind(8764).sync();
//5 等待关闭
cf1.channel().closeFuture().sync();
//cf2.channel().closeFuture().sync();
pGroup.shutdownGracefully();
cGroup.shutdownGracefully();
}
}
ServerHandler.java
package bhz.netty.helloworld;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
public class ServerHandler extends ChannelHandlerAdapter {
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println("server channel active... ");
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg)
throws Exception {
ByteBuf buf = (ByteBuf) msg;
byte[] req = new byte[buf.readableBytes()];
buf.readBytes(req);
String body = new String(req, "utf-8");
System.out.println("Server :" + body );
String response = "进行返回给客户端的响应:" + body ;
ctx.writeAndFlush(Unpooled.copiedBuffer(response.getBytes()));
//.addListener(ChannelFutureListener.CLOSE);
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx)
throws Exception {
System.out.println("读完了");
ctx.flush();
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable t)
throws Exception {
ctx.close();
}
}
拆包粘包问题
![img_ad55a9dbf9e44e2b718652bef9931e75.png](https://yqfile.alicdn.com/img_ad55a9dbf9e44e2b718652bef9931e75.png?x-oss-process=image/resize,w_1400/format,webp)
![img_949f2b447fdd2e4ca0d5139a06d6dbf1.png](https://yqfile.alicdn.com/img_949f2b447fdd2e4ca0d5139a06d6dbf1.png?x-oss-process=image/resize,w_1400/format,webp)
![img_fdc709617b5d139c31aecf91ff9a0ee1.png](https://yqfile.alicdn.com/img_fdc709617b5d139c31aecf91ff9a0ee1.png?x-oss-process=image/resize,w_1400/format,webp)