想在Netty的channel中传递字符串，需要在客户端Client设置sc.pipeline().addLast(new StringEncoder());服务端Server设置sc.pipeline().addLast(new StringDecoder());就可以了；
客户端代码：
package com.netty.client;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;import io.netty.handler.codec.string.StringDecoder;import io.netty.handler.codec.string.StringEncoder;public class Client {public static void main(String[] args) throws InterruptedException {EventLoopGroup workgroup = new NioEventLoopGroup();Bootstrap b = new Bootstrap();b.group(workgroup);b.channel(NioSocketChannel.class);b.handler(new ChannelInitializer<SocketChannel>() {@Overrideprotected void initChannel(SocketChannel sc) throws Exception {sc.pipeline().addLast(new StringEncoder());sc.pipeline().addLast(new ClientHandler());}});ChannelFuture future = b.connect("127.0.0.1", 8080).sync();future.channel().writeAndFlush("asda");future.channel().closeFuture().sync();workgroup.shutdownGracefully();}}服务端代码：
package com.netty.server;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 io.netty.handler.codec.string.StringDecoder;import io.netty.handler.logging.LogLevel;import io.netty.handler.logging.LoggingHandler;public class Server {public static void main(String[] args) throws InterruptedException {EventLoopGroup bossgroup = new NioEventLoopGroup();EventLoopGroup workgroup = new NioEventLoopGroup();ServerBootstrap sb = new ServerBootstrap();sb.channel(NioServerSocketChannel.class);sb.group(bossgroup,workgroup);sb.handler(new LoggingHandler(LogLevel.INFO));sb.childHandler(new ChannelInitializer<SocketChannel>() {@Overrideprotected void initChannel(SocketChannel sc) throws Exception {sc.pipeline().addLast(new StringDecoder());sc.pipeline().addLast(new ServerHandler());}});ChannelFuture future = sb.bind(8080).sync();future.channel().closeFuture().sync();workgroup.shutdownGracefully();bossgroup.shutdownGracefully();}}
package com.netty.server;import java.nio.charset.Charset;import io.netty.buffer.ByteBuf;import io.netty.channel.ChannelHandlerAdapter;import io.netty.channel.ChannelHandlerContext;import io.netty.util.CharsetUtil;import io.netty.util.ReferenceCountUtil;public class ServerHandler extends ChannelHandlerAdapter { ???@Override ???public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { ???????try {
//这里可以直接获取str ???????????String str = (String)msg; ???????????System.out.println(str); ???????} finally { ???????????ReferenceCountUtil.release(msg); ???????} ????} ???@Override ???public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { ???}}那么如果服务端要给客户端也返回String类型的，只需要在服务端和客户端都加上sc.pipeline().addLast(new StringEncoder());sc.pipeline().addLast(new StringDecoder());就好了。
Netty传递字符串
原文地址：https://www.cnblogs.com/TravisGrady/p/9337418.html