前言介绍
Netty开发中,客户端与服务端需要保持同样的;半包粘包处理,编码解码处理、收发数据方式,这样才能保证数据通信正常。在前面NettyServer的章节中我们也同样处理了;半包粘包、编码解码等,为此在本章节我们可以把这些知识模块开发到NettyClient中。本章节涉及到的知识点有;LineBasedFrameDecoder、StringDecoder、StringEncoder、ChannelInboundHandlerAdapter等。
开发环境
1、jdk1.8【jdk1.7以下只能部分支持netty】
2、Netty4.1.36.Final【netty3.x 4.x 5每次的变化较大,接口类名也随着变化】
3、telnet 测试【可以现在你的win7机器上测试这个命令,用于链接到服务端的测试命令】
代码示例
itstack-demo-netty-1-08 └── src ├── main │ └── java │ └── org.itstack.demo.netty.client │ ├── MyChannelInitializer.java │ ├── MyClientHandler.java │ └── NettyClient.java └── test └── java └── org.itstack.demo.netty.test └── ApiTest.java
MyChannelInitializer.java
/** * 虫洞栈:https://bugstack.cn * 公众号:bugstack虫洞栈 {获取学习源码} * Create by fuzhengwei on 2019 */ public class MyChannelInitializer extends ChannelInitializer<SocketChannel> { @Override protected void initChannel(SocketChannel channel) throws Exception { // 基于换行符号 channel.pipeline().addLast(new LineBasedFrameDecoder(1024)); // 解码转String,注意调整自己的编码格式GBK、UTF-8 channel.pipeline().addLast(new StringDecoder(Charset.forName("GBK"))); // 解码转String,注意调整自己的编码格式GBK、UTF-8 channel.pipeline().addLast(new StringEncoder(Charset.forName("GBK"))); // 在管道中添加我们自己的接收数据实现方法 channel.pipeline().addLast(new MyClientHandler()); } }
MyClientHandler.java
/** * 虫洞栈:https://bugstack.cn * 公众号:bugstack虫洞栈 {获取学习源码} * Create by fuzhengwei on 2019 */ public class MyClientHandler extends ChannelInboundHandlerAdapter { /** * 当客户端主动链接服务端的链接后,这个通道就是活跃的了。也就是客户端与服务端建立了通信通道并且可以传输数据 */ @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { SocketChannel channel = (SocketChannel) ctx.channel(); System.out.println("链接报告开始"); System.out.println("链接报告信息:本客户端链接到服务端。channelId:" + channel.id()); System.out.println("链接报告IP:" + channel.localAddress().getHostString()); System.out.println("链接报告Port:" + channel.localAddress().getPort()); System.out.println("链接报告完毕"); //通知客户端链接建立成功 String str = "通知服务端链接建立成功" + " " + new Date() + " " + channel.localAddress().getHostString() + "\r\n"; ctx.writeAndFlush(str); } /** * 当客户端主动断开服务端的链接后,这个通道就是不活跃的。也就是说客户端与服务端的关闭了通信通道并且不可以传输数据 */ @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { System.out.println("断开链接" + ctx.channel().localAddress().toString()); } @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { //接收msg消息{与上一章节相比,此处已经不需要自己进行解码} System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + " 接收到消息:" + msg); //通知客户端链消息发送成功 String str = "客户端收到:" + new Date() + " " + msg + "\r\n"; ctx.writeAndFlush(str); } /** * 抓住异常,当发生异常的时候,可以做一些相应的处理,比如打印日志、关闭链接 */ @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { ctx.close(); System.out.println("异常信息:\r\n" + cause.getMessage()); } }
NettyClient.java
/** * 虫洞栈:https://bugstack.cn * 公众号:bugstack虫洞栈 {获取学习源码} * Create by fuzhengwei on 2019 */ public class NettyClient { public static void main(String[] args) { new NettyClient().connect("127.0.0.1", 7397); } private void connect(String inetHost, int inetPort) { EventLoopGroup workerGroup = new NioEventLoopGroup(); try { Bootstrap b = new Bootstrap(); b.group(workerGroup); b.channel(NioSocketChannel.class); b.option(ChannelOption.AUTO_READ, true); b.handler(new MyChannelInitializer()); ChannelFuture f = b.connect(inetHost, inetPort).sync(); System.out.println("itstack-demo-netty client start done. {关注公众号:bugstack虫洞栈,获取源码}"); f.channel().closeFuture().sync(); } catch (InterruptedException e) { e.printStackTrace(); } finally { workerGroup.shutdownGracefully(); } } }
测试结果
启动模拟器NetAssist 设置TCP Server
启动客户端NettyClient
执行结果
/** * 虫洞栈:https://bugstack.cn * 公众号:bugstack虫洞栈 {获取学习源码} * Create by fuzhengwei on 2019 */ public class NettyClient { public static void main(String[] args) { new NettyClient().connect("127.0.0.1", 7397); } private void connect(String inetHost, int inetPort) { EventLoopGroup workerGroup = new NioEventLoopGroup(); try { Bootstrap b = new Bootstrap(); b.group(workerGroup); b.channel(NioSocketChannel.class); b.option(ChannelOption.AUTO_READ, true); b.handler(new MyChannelInitializer()); ChannelFuture f = b.connect(inetHost, inetPort).sync(); System.out.println("itstack-demo-netty client start done. {关注公众号:bugstack虫洞栈,获取源码}"); f.channel().closeFuture().sync(); } catch (InterruptedException e) { e.printStackTrace(); } finally { workerGroup.shutdownGracefully(); } } }