看了好几天的netty实战,慢慢摸索,虽然还没有摸着很多门道,但今天还是把之前想加入到项目里的
一些想法实现了,算是有点信心了吧(讲真netty对初学者还真的不是很友好......)
首先,当然是在SpringBoot项目里添加netty的依赖了,注意不要用netty5的依赖,因为已经废弃了
<!--netty--><dependency> <groupId>io.netty</groupId> <artifactId>netty-all</artifactId> <version>4.1.32.Final</version></dependency> |
将端口和IP写入application.yml文件里,我这里是我云服务器的内网IP,如果是本机测试,用127.0.0.1就ok
netty: port: 7000 url: 172.16.0.7 |
在这之后,开始写netty的服务器,这里服务端的逻辑就是将客户端发来的信息返回回去
因为采用依赖注入的方法实例化netty,所以加上@Component注解
1 package com.safelocate.app.nettyServer; 2 3 import io.netty.bootstrap.ServerBootstrap; 4 import io.netty.channel.*; 5 import io.netty.channel.nio.NioEventLoopGroup; 6 import io.netty.channel.socket.nio.NioServerSocketChannel; 7 import org.apache.log4j.Logger; 8 import org.springframework.stereotype.Component; 9 10 import java.net.InetSocketAddress;11 12 @Component13 public class NettyServer {14 //logger15 private static final Logger logger = Logger.getLogger(NettyServer.class);16 public void start(InetSocketAddress address){17 EventLoopGroup bossGroup = new NioEventLoopGroup(1);18 EventLoopGroup workerGroup = new NioEventLoopGroup();19 try {20 ServerBootstrap bootstrap = new ServerBootstrap()21 .group(bossGroup,workerGroup)22 .channel(NioServerSocketChannel.class)23 .localAddress(address)24 .childHandler(new ServerChannelInitializer())25 .option(ChannelOption.SO_BACKLOG, 128)26 .childOption(ChannelOption.SO_KEEPALIVE, true);27 // 绑定端口，开始接收进来的连接28 ChannelFuture future = bootstrap.bind(address).sync();29 logger.info("Server start listen at " + address.getPort());30 future.channel().closeFuture().sync();31 } catch (Exception e) {32 e.printStackTrace();33 bossGroup.shutdownGracefully();34 workerGroup.shutdownGracefully();35 }36 }37 38 }
Server.java
当然,这里的ServerChannelInitializer是我自己定义的类,这个类是继承ChannelInitializer<SocketChannel>的,里面设置出站和入站的编码器和解码器
package com.safelocate.app.nettyServer;import io.netty.channel.ChannelInitializer;import io.netty.channel.socket.SocketChannel;import io.netty.handler.codec.string.StringDecoder;import io.netty.handler.codec.string.StringEncoder;import io.netty.util.CharsetUtil;public class ServerChannelInitializer extends ChannelInitializer<SocketChannel> {
@Override protected void initChannel(SocketChannel channel) throws Exception {
channel.pipeline().addLast("decoder",new StringDecoder(CharsetUtil.UTF_8));
channel.pipeline().addLast("encoder",new StringEncoder(CharsetUtil.UTF_8));
channel.pipeline().addLast(new ServerHandler());
}
}
ServerChannelinitializer.java
最好注意被别decoder和encoder写成了一样的,不然会出问题(我之前就是不小心都写成了StringDecoder...)
在这之后就是设置ServerHandler来处理一些简单的逻辑了
package com.safelocate.app.nettyServer;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.ChannelInboundHandlerAdapter;import io.netty.channel.SimpleChannelInboundHandler;import java.io.IOException;import java.io.OutputStream;import java.io.PrintWriter;import java.net.InetAddress;import java.net.Socket;public class ServerHandler extends ChannelInboundHandlerAdapter {
@Override public void channelActive(ChannelHandlerContext ctx) {
System.out.println("channelActive----->");
}
@Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println("server channelRead......");
System.out.println(ctx.channel().remoteAddress()+"----->Server :"+ msg.toString()); //将客户端的信息直接返回写入ctx
ctx.write("server say :"+msg); //刷新缓存区 ctx.flush();
}
@Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
ServerHandler.java
准备工作到这里,现在要做到就是去启动这个程序
将AppApplication实现CommandLineRunner这个接口,这个接口可以用来再启动SpringBoot时同时启动其他功能,比如配置,数据库连接等等
然后重写run方法,在run方法里启动netty服务器,Server类用@AutoWired直接实例化
package com.safelocate.app;import com.safelocate.app.nettyServer.NettyServer;import io.netty.channel.ChannelFuture;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.beans.factory.annotation.Value;import org.springframework.boot.CommandLineRunner;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import java.net.InetAddress;import java.net.InetSocketAddress;
@SpringBootApplicationpublic class AppApplication implements CommandLineRunner {
@Value("${netty.port}") private int port;
@Value("${netty.url}") private String url;
@Autowired private NettyServer server; public static void main(String[] args) {
SpringApplication.run(AppApplication.class, args);
}
@Override public void run(String... args) throws Exception {
InetSocketAddress address = new InetSocketAddress(url,port);
System.out.println("run .... . ... "+url);
server.start(address);
}
}
AppApplication.java
ok,到这里服务端已经写完,本地我也已经测试完,现在需要打包部署服务器,当然这个程序只为练手...
控制台输入mvn clean package -D skipTests 然后将jar包上传服务器,在这之后,需要在腾讯云/阿里云那边配置好安全组,将之前yml文件里设定的端口的入站
规则设置好,不然访问会被拒绝
之后java -jar命令运行,如果需保持后台一直运行 就用nohup命令,可以看到程序已经跑起来了,等待客户端连接交互
之后就是写客户端了,客户端其实是依葫芦画瓢,跟上面类似
Handler
package client;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.ChannelInboundHandlerAdapter;public class ClientHandler extends ChannelInboundHandlerAdapter {
@Override public void channelActive(ChannelHandlerContext ctx) {
System.out.println("ClientHandler Active");
}
@Override public void channelRead(ChannelHandlerContext ctx, Object msg) {
System.out.println("--------");
System.out.println("ClientHandler read Message:"+msg);
}
@Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
ClientHandler.java
ChannelInitializer
package client;import io.netty.channel.ChannelInitializer;import io.netty.channel.ChannelPipeline;import io.netty.channel.socket.SocketChannel;import io.netty.handler.codec.string.StringDecoder;import io.netty.handler.codec.string.StringEncoder;import io.netty.util.CharsetUtil;public class ClientChannelInitializer extends ChannelInitializer<SocketChannel> { protected void initChannel(SocketChannel channel) throws Exception {
ChannelPipeline p = channel.pipeline();
p.addLast("decoder", new StringDecoder(CharsetUtil.UTF_8));
p.addLast("encoder", new StringEncoder(CharsetUtil.UTF_8));
p.addLast(new ClientHandler());
}
}
ClientChannelInitializer
主函数所在类,即客户端
package client;import io.netty.bootstrap.Bootstrap;import io.netty.channel.*;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 { static final String HOST = System.getProperty("host", "服务器的IP地址"); static final int PORT = Integer.parseInt(System.getProperty("port", "7000")); static final int SIZE = Integer.parseInt(System.getProperty("size", "256")); public static void main(String[] args) throws Exception {
sendMessage("hhhh");
} public static void sendMessage(String content) throws InterruptedException{ // Configure the client.
EventLoopGroup group = new NioEventLoopGroup(); try {
Bootstrap b = new Bootstrap();
b.group(group)
.channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(new ChannelInitializer<SocketChannel>() {
@Override public void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline p = ch.pipeline();
p.addLast("decoder", new StringDecoder());
p.addLast("encoder", new StringEncoder());
p.addLast(new ClientHandler());
}
});
ChannelFuture future = b.connect(HOST, PORT).sync();
future.channel().writeAndFlush(content);
future.channel().closeFuture().sync();
} finally {
group.shutdownGracefully();
}
}
}
Client.java
启动客户端,这里就是简单发送一条"hhhh",可以看到客户端已经收到服务器发来的信息
然后再看服务端,也有相应的信息打印
推荐一个挺好的学netty的博客,https://blog.csdn.net/linuu/article/details/51306480,搭配netty实战这本书一起学习效果很好
实战：根据上面完成一个简（la）单（ji）的聊天室应用（无界面，基于CMD）
这里服务端可以单独分出来可以单独作为一个工程打包为jar，万万没必要Springboot，但这里懒得改了，就还是当后台用吧hhh
首先，服务端需要展示的就是每个人所发出来的信息，和对上线人数下线人数进行实时的更新，之前更新是利用一个静态变量,
但是这样硬核了一点,这里正好要用到群发的功能,所以我们需要一个list来存放Channel,然后将这个list的size作为在线人数就好了
群发就遍历这个数组,然后writeAndFlush
package com.safelocate.app.nettyServer;import io.netty.channel.*;import io.netty.channel.group.ChannelGroup;import io.netty.channel.group.DefaultChannelGroup;import io.netty.util.concurrent.GlobalEventExecutor;public class ServerHandler extends ChannelInboundHandlerAdapter { private static ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
@Override public void handlerAdded(ChannelHandlerContext ctx) throws Exception{
channels.add(ctx.channel());//加入ChannelGroup
System.out.println(ctx.channel().id()+" come into the chattingroom,"+"Online: "+channels.size());
}
@Override public void handlerRemoved(ChannelHandlerContext context){
System.out.println(context.channel().id()+" left the chattingroom,"+"Online: "+channels.size());
}
@Override public void channelActive(ChannelHandlerContext ctx) {
}
@Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { //打印消息然后群发 System.out.println(msg.toString()); for (Channel channel:channels){
channel.writeAndFlush(msg.toString());
}
}
@Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
System.out.println(ctx.channel().id()+" occurred into error,"+"Online: "+channels.size());
ctx.close();
}
}
ServerHandler
照样，打包成jar，java -jar命令运行就行，哦对由于这里是本地测试，所以yml文件中的IP应该换成127.0.0.1
接下来是客户端，首先明确的就是用户需要输入信息，所以肯定要用到输入函数，比如Scanner，另外，服务端需要知道每一个人的身份，这里
简单的用昵称来代替，在发送的时候将名字也一并发过去，这样就能简单分辨是谁发的信息（其实这样做主要是因为没来得及写数据库升级复杂一点的逻辑）
所以，在之前发信息的函数里稍微处理一下就行，即增加信息输入模块
public static void sendMessage() throws InterruptedException{ // Configure the client.
EventLoopGroup group = new NioEventLoopGroup(); try {
Bootstrap b = new Bootstrap();
b.group(group)
.channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(new ChannelInitializer<SocketChannel>() {
@Override public void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline p = ch.pipeline();
p.addLast("decoder", new StringDecoder(CharsetUtil.UTF_8));
p.addLast("encoder", new StringEncoder(CharsetUtil.UTF_8));
p.addLast(new ClientHandler());
}
});
ChannelFuture future = b.connect(HOST, PORT).sync();
Scanner sca=new Scanner(System.in); while (true){
String str=sca.nextLine();//输入的内容
if (str.equals("exit")) break;//如果是exit则退出
future.channel().writeAndFlush(name+"-: "+str);//将名字和信息内容一起发过去 }
future.channel().closeFuture().sync();
} finally {
group.shutdownGracefully();
}
}
sendMessage（）
之后把IP改成127.0.0.1就行，打包的时候，需要在pom文件中添加打包插件，特别注意的是要制定mainClass，不然运行时会报“没有主清单属性”
这里贴上插件配置，这个插件其实对于所有Java程序都适用，因为他会把依赖全带上
<!-- java编译插件 -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
<mainClass>client.Client</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>copy</id>
<phase>install</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/lib</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
pom
打包后之后就是运行了，效果大概是这样.。。。。。。
哈哈哈哈有时间再完善一下
随时随地看视频
