以下是一个简单的Java Netty框架搭建示例,它实现了一个简单的Echo服务器,即客户端发送什么数据,服务器就返回什么数据。
- 创建Maven项目,并在pom.xml文件中添加以下依赖:
<dependencies> <dependency> <groupId>io.netty</groupId> <artifactId>netty-all</artifactId> <version>4.1.65.Final</version> </dependency> </dependencies>
- 创建Netty服务器主类EchoServer.java,实现Echo服务器的启动与关闭。
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 EchoServer { private final int port; public EchoServer(int port) { this.port = port; } public void start() throws Exception { EventLoopGroup group = new NioEventLoopGroup(); try { ServerBootstrap b = new ServerBootstrap(); b.group(group) .channel(NioServerSocketChannel.class) .localAddress(port) .childHandler(new ChannelInitializer<SocketChannel>() { @Override public void initChannel(SocketChannel ch) throws Exception { ch.pipeline().addLast(new EchoServerHandler()); } }) .option(ChannelOption.SO_BACKLOG, 128) .childOption(ChannelOption.SO_KEEPALIVE, true); ChannelFuture f = b.bind().sync(); System.out.println("EchoServer started and listening for connections on " + f.channel().localAddress()); f.channel().closeFuture().sync(); } finally { group.shutdownGracefully().sync(); } } public static void main(String[] args) throws Exception { if (args.length != 1) { System.err.println("Usage: " + EchoServer.class.getSimpleName() + " <port>"); return; } int port = Integer.parseInt(args[0]); new EchoServer(port).start(); } }
- 创建Echo服务器处理类EchoServerHandler.java,实现Echo服务器处理逻辑。
import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; public class EchoServerHandler extends ChannelInboundHandlerAdapter { @Override public void channelRead(ChannelHandlerContext ctx, Object msg) { ByteBuf in = (ByteBuf) msg; System.out.println("Server received: " + in.toString(io.netty.util.CharsetUtil.UTF_8)); ctx.write(in); } @Override public void channelReadComplete(ChannelHandlerContext ctx) { ctx.flush(); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { cause.printStackTrace(); ctx.close(); } }
- 运行Echo服务器。 在IDE中运行EchoServer.java类的main方法即可启动Echo服务器。运行后,可以使用telnet命令连接Echo服务器。
telnet localhost 8080
连接成功后,输入任意字符串,服务器就会返回相同的字符串。 以上就是一个简单的Java Netty框架搭建示例,希望能够帮助你快速入门Netty框架。
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