Netty作为服务器和普通Java Socket客户端传输数据

比眉伴天荒 2023-10-18 17:01 103阅读 0赞

现在用Netty写一个服务器Server，服务器端绑定本地端口80等待连接，当有客户端Socket连接过来后，就发送字符串“hello，world！”给客户端。客户端连接服务器，连接成功则读取字符串并打印出来，然后关闭socket连接。

服务器：

package zhangphil.server;
    
    import java.util.logging.Level;
    import java.util.logging.Logger;
    
    import io.netty.bootstrap.ServerBootstrap;
    import io.netty.channel.ChannelFuture;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelInboundHandlerAdapter;
    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;
    import io.netty.handler.codec.string.StringDecoder;
    import io.netty.handler.codec.string.StringEncoder;
    import io.netty.handler.logging.LogLevel;
    import io.netty.handler.logging.LoggingHandler;
    
    public class Server {
    	private final int port = 80;
    
    	public Server() throws Exception {
    		EventLoopGroup bossGroup = new NioEventLoopGroup();
    		EventLoopGroup workerGroup = new NioEventLoopGroup();
    
    		ServerBootstrap b = new ServerBootstrap();
    		b.group(bossGroup, workerGroup).option(ChannelOption.SO_KEEPALIVE, true).channel(NioServerSocketChannel.class)
    				.option(ChannelOption.SO_BACKLOG, 128).handler(new LoggingHandler(LogLevel.INFO))
    				.childHandler(new ChannelInitializer<SocketChannel>() {
    					@Override
    					public void initChannel(SocketChannel sc) throws Exception {
    						sc.pipeline().addLast(new StringEncoder());// 发送字符串的编码器。
    						sc.pipeline().addLast(new StringDecoder());// 接收到字符串的解码器。
    						sc.pipeline().addLast(new MyServerHandler());
    					}
    				});
    
    		// 绑定端口，开始接收进来的连接。
    		ChannelFuture cf = b.bind(port).sync();
    
    		// 等待服务器关闭Socket。
    		cf.channel().closeFuture().sync();
    	}
    
    	public class MyServerHandler extends ChannelInboundHandlerAdapter {
    
    		private final Logger logger = Logger.getLogger(MyServerHandler.class.getName());
    
    		@Override
    		public void channelActive(ChannelHandlerContext ctx) throws Exception {
    			System.out.println("连接激活");
    			ctx.writeAndFlush("hello,world!"); // 若没有StringEncoder，则发送不出去字符串。
    			System.out.println("写入完成");
    		}
    
    		@Override
    		public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
    
    		}
    
    		@Override
    		public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
    
    		}
    
    		@Override
    		public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
    			logger.log(Level.WARNING, "发生错误，关闭链接。", cause);
    			ctx.close();
    		}
    	}
    
    	public static void main(String[] args) {
    		try {
    			new Server();
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    }

客户端用普通Java的Socket实现：

import java.io.BufferedInputStream;
    import java.net.Socket;
    
    public class Client {
    	public Client() throws Exception {
    		Socket socket = new Socket("localhost", 80);
    
    		BufferedInputStream bis = new BufferedInputStream(socket.getInputStream());
    
    		byte[] buf = new byte[256];
    
    		System.out.println("开始读数据...");
    		int count = bis.read(buf);
    		System.out.println("读取数据数量:" + count);
    		System.out.println(new String(buf));
    
    		bis.close();
    		socket.close();
    	}
    
    	public static void main(String[] args) {
    		try {
    			new Client();
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    }

服务器端输出：

![20190412205814749.png][]

客户端输出：

![20190412205822745.png][]

[20190412205814749.png]: https://img-blog.csdnimg.cn/20190412205814749.png
[20190412205822745.png]: https://img-blog.csdnimg.cn/20190412205822745.png