原文链接：https://blog.csdn.net/qq_33227649/article/details/78317912
今天准备学学声明显赫的Netty框架，自然要先学会怎么搭建一个简单的Netty开发环境啦。话不多说，下面进入正文。
编辑器方面自然是推荐IntelJ idea了，idea的强大不必多说，百度一下你就知道。哈哈
下面就是准备Netty的jar包了，如果你会maven的话自然是使用maven最为方便了。只需要在pom文件中导入以下几行
<!-- https://mvnrepository.com/artifact/io.netty/netty-all -->
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.16.Final</version>
</dependency>
当然啦，不会maven的也不用愁，可以在官网直接下载jar包，点击跳转。并在编辑器中将下载的jar包引入你的lib中，就可以愉快的开始Netty开发了
下面贴一个简单的netty案例
一、 服务端代码
1. EchoServerHandler.java
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;
@Sharable
public class EchoServerHandler extends ChannelInboundHandlerAdapter{
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
//将客户端传入的消息转换为Netty的ByteBuf类型
ByteBuf in = (ByteBuf) msg;
// 在控制台打印传入的消息
System.out.println(
"Server received: " + in.toString(CharsetUtil.UTF_8)
);
//将接收到的消息写给发送者，而不冲刷出站消息
ctx.write(in);
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
// 将未处决消息冲刷到远程节点， 并且关闭该Channel
ctx.writeAndFlush(Unpooled.EMPTY_BUFFER)
.addListener(ChannelFutureListener.CLOSE);
}
/**
* 异常处理
* @param ctx
* @param cause
* @throws Exception
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
//打印异常栈跟踪
cause.printStackTrace();
// 关闭该Channel
ctx.close();
}
}2. EchoServer.java
import io.netty.bootstrap.ServerBootstrap;
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.NioServerSocketChannel;
import java.net.InetSocketAddress;
public class EchoServer {
private final static int port = 8080;
public static void main(String[] args) {
start();
}
private static void start() {
final EchoServerHandler serverHandler = new EchoServerHandler();
// 创建EventLoopGroup
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
// 创建EventLoopGroup
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
//指定所使用的NIO传输Channel
.channel(NioServerSocketChannel.class)
//使用指定的端口设置套接字地址
.localAddress(new InetSocketAddress(port))
// 添加一个EchoServerHandler到Channle的ChannelPipeline
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
//EchoServerHandler被标注为@shareable,所以我们可以总是使用同样的案例
socketChannel.pipeline().addLast(serverHandler);
}
});
try {
// 异步地绑定服务器;调用sync方法阻塞等待直到绑定完成
ChannelFuture f = b.bind().sync();
// 获取Channel的CloseFuture，并且阻塞当前线程直到它完成
f.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
// 优雅的关闭EventLoopGroup，释放所有的资源
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
二、 客户端代码
1. EchoClientHandler.java
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.util.CharsetUtil;
@Sharable
public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
//当被通知Channel是活跃的时候，发送一条消息
ctx.writeAndFlush(Unpooled.copiedBuffer("Netty rocks!", CharsetUtil.UTF_8));
}
@Override
protected void channelRead0(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf) throws Exception {
System.out.println(
"Client received: " + byteBuf.toString(CharsetUtil.UTF_8)
);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
2. EchoClient.java
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;
import java.net.InetSocketAddress;
public class EchoClient {
private final static String HOST = "localhost";
private final static int PORT = 8080;
public static void start() {
EventLoopGroup group = new NioEventLoopGroup();
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(group)
.channel(NioSocketChannel.class)
.remoteAddress(new InetSocketAddress(HOST, PORT))
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
socketChannel.pipeline().addLast(new EchoClientHandler());
}
});
try {
ChannelFuture f = bootstrap.connect().sync();
f.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}finally {
group.shutdownGracefully();
}
}
public static void main(String[] args) {
start();
}
}先后运行EchoServer.java和EchoClient.java.如果控制台分别打印了
Server received: Netty rocks!
和
Client received: Netty rocks!