概述
netty是一个高性能的socket框架。
源码
https://github.com/netty/netty
快速入门
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<build>
<plugins>
<!--【必用插件】用于设置项目jdk版本-->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>8</source>
<target>8</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.20.Final</version>
</dependency>
<dependency>
<groupId>com.google.protobuf</groupId>
<artifactId>protobuf-java</artifactId>
<version>3.2.0</version>
</dependency>
</dependencies>
客户端
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public void connect(String ip, int port) {
NioEventLoopGroup workerGroup = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(workerGroup)
.channel(NioSocketChannel.class)
.option(ChannelOption.SO_KEEPALIVE, true)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
ChannelPipeline pipeline = socketChannel.pipeline();
pipeline.addLast("intDecoder", new ProtobufVarint32FrameDecoder());
pipeline.addLast("intEncoder", new ProtobufVarint32LengthFieldPrepender());
pipeline.addLast("protobufDecoder", new ProtobufDecoder(MessagePOJO.Message.getDefaultInstance()));
pipeline.addLast("protobufEncoder", new ProtobufEncoder());
pipeline.addLast(new SimpleClientHandler());
}
});
ChannelFuture channelFuture = bootstrap.connect(ip, port).sync();
if (channelFuture.isSuccess()) System.out.println("连接成功！！！！");
else System.out.println("连接失败");
channelFuture.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
workerGroup.shutdownGracefully();
}
}
———-另一种———————–
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public void connect(String ip, int port) {
EventLoopGroup group = new NioEventLoopGroup();// 开启工作线程组
try {
Bootstrap bootstrap = new Bootstrap(); //创建一个和服务端相对应的server
bootstrap.group(group) //设置线程组
.channel(NioSocketChannel.class) //使用NioSocketChannel作为客户端的通道实现
.handler(new ChannelInitializer<SocketChannel>() {//设置回调函数
@Override
protected void initChannel(SocketChannel ch) {
ch.pipeline().addLast(new NettyClientHandler());
}
});
System.out.println("netty client start。。");
ChannelFuture cf = bootstrap.connect("127.0.0.1", 9000).sync();//启动客户端去连接服务器端
//对通道关闭进行监听
cf.channel().closeFuture().sync();
} finally {
group.shutdownGracefully();//关闭线程组
}
}
服务端
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public void startServer() {
NioEventLoopGroup bossGroup = new NioEventLoopGroup();
NioEventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup)
.option(ChannelOption.SO_BACKLOG, 128)
.childOption(ChannelOption.SO_KEEPALIVE, true)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
ChannelPipeline pipeline = socketChannel.pipeline();
pipeline.addLast("intDecoder", new ProtobufVarint32FrameDecoder());
pipeline.addLast("intEncoder", new ProtobufVarint32LengthFieldPrepender());
pipeline.addLast("protobufDecoder", new ProtobufDecoder(MessagePOJO.Message.getDefaultInstance()));
pipeline.addLast(new SimpleServerHandler());
}
});
ChannelFuture channelFuture = serverBootstrap.bind(port).sync();
if (channelFuture.isSuccess()) System.out.println("服务器开启成功！！！！");
else System.out.println("服务器开启失败");
channelFuture.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
}
———-另一种———————–
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public void startServer() {
EventLoopGroup bossGroup = new NioEventLoopGroup(1);//新建线程组,用于处理请求
EventLoopGroup workerGroup = new NioEventLoopGroup();//真正工作的线程组
try {
ServerBootstrap bootstrap = new ServerBootstrap();//创建一个server,相当于NIO的server
bootstrap.group(bossGroup, workerGroup) //采用链式编程,将两个线程组加入到server中
.channel(NioServerSocketChannel.class) //设置一个信道,相当于NIO中的ServerSocketChannel
.option(ChannelOption.SO_BACKLOG, 1024) //对服务端给予一些设置
.childHandler(new ChannelInitializer<SocketChannel>() {//给予初始化,并加入回调函数
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new NettyServerHandler());
}
});
System.out.println("netty server start。。");
ChannelFuture cf = bootstrap.bind(9000).sync();//绑定端口,sync方法是等待异步操作执行完毕
cf.channel().closeFuture().sync();//对通道关闭进行监听，closeFuture是异步操作，监听通道关闭
// 通过sync方法同步等待通道关闭处理完毕，这里会阻塞等待通道关闭完成
} finally {
bossGroup.shutdownGracefully(); //关闭处理请求的线程组
workerGroup.shutdownGracefully();//关闭真正工作的线程组
}
}
回调
服务端回调
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public class NettyServerHandler extends ChannelInboundHandlerAdapter {
//当客户端连接服务器完成就会触发该方法
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
ByteBuf buf = Unpooled.copiedBuffer("HelloServer".getBytes(CharsetUtil.UTF_8));
ctx.writeAndFlush(buf);
}
//当通道有读取事件时会触发，即客户端发送数据给服务端
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
ByteBuf buf = (ByteBuf) msg;
System.out.println("收到客户端的消息:" + buf.toString(CharsetUtil.UTF_8));
System.out.println("客户端的地址： " + ctx.channel().remoteAddress());
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
System.out.println("我收到了异常");
cause.printStackTrace();
ctx.close();
}
}
客户端回调
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public class NettyClientHandler extends ChannelInboundHandlerAdapter {
/**
* 当客户端连接服务器完成就会触发该方法
*
* @param ctx 设置好的信道,相当于上下文
*/
@Override
public void channelActive(ChannelHandlerContext ctx) {
ByteBuf buf = Unpooled.copiedBuffer("HelloServer".getBytes(CharsetUtil.UTF_8));
ctx.writeAndFlush(buf);
}
//当通道有读取事件时会触发，即服务端发送数据给客户端
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
ByteBuf buf = (ByteBuf) msg;
System.out.println("收到服务端的消息:" + buf.toString(CharsetUtil.UTF_8));
System.out.println("服务端的地址： " + ctx.channel().remoteAddress());
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}