看了好幾天的netty實戰,慢慢摸索,雖然還沒有摸着很多門道,但今天還是把之前想加入到項目裏的
一些想法實現了,算是有點信心了吧(講真netty對初學者還真的不是很友好......)
首先,當然是在SpringBoot項目裏添加netty的依賴了,注意不要用netty5的依賴,因爲已經廢棄了
<!--netty-->
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.32.Final</version>
</dependency>
將端口和IP寫入application.yml文件裏,我這裏是我雲服務器的內網IP,如果是本機測試,用127.0.0.1就ok
netty: port: 7000 url: 172.16.0.7
在這之後,開始寫netty的服務器,這裏服務端的邏輯就是將客戶端發來的信息返回回去
因爲採用依賴注入的方法實例化netty,所以加上@Component註解
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 @Component 13 public class NettyServer { 14 //logger 15 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 // 綁定端口，開始接收進來的連接 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 }
當然,這裏的ServerChannelInitializer是我自己定義的類,這個類是繼承ChannelInitializer<SocketChannel>的,裏面設置出站和入站的編碼器和解碼器
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()); } }
最好注意被別decoder和encoder寫成了一樣的,不然會出問題(我之前就是不小心都寫成了StringDecoder...)
在這之後就是設置ServerHandler來處理一些簡單的邏輯了
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()); //將客戶端的信息直接返回寫入ctx ctx.write("server say :"+msg); //刷新緩存區 ctx.flush(); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); ctx.close(); } }
準備工作到這裏,現在要做到就是去啓動這個程序
將AppApplication實現CommandLineRunner這個接口,這個接口可以用來再啓動SpringBoot時同時啓動其他功能,比如配置,數據庫連接等等
然後重寫run方法,在run方法裏啓動netty服務器,Server類用@AutoWired直接實例化
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; @SpringBootApplication public 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); } }
ok,到這裏服務端已經寫完,本地我也已經測試完,現在需要打包部署服務器,當然這個程序只爲練手...
控制檯輸入mvn clean package -D skipTests 然後將jar包上傳服務器,在這之後,需要在騰訊雲/阿里雲那邊配置好安全組,將之前yml文件裏設定的端口的入站
規則設置好,不然訪問會被拒絕
之後java -jar命令運行,如果需保持後臺一直運行 就用nohup命令,可以看到程序已經跑起來了,等待客戶端連接交互
之後就是寫客戶端了,客戶端其實是依葫蘆畫瓢,跟上面類似
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(); } }
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()); } }
主函數所在類,即客戶端
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", "服務器的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(); } } }
啓動客戶端,這裏就是簡單發送一條"hhhh",可以看到客戶端已經收到服務器發來的信息
然後再看服務端,也有相應的信息打印
推薦一個挺好的學netty的博客,https://blog.csdn.net/linuu/article/details/51306480,搭配netty實戰這本書一起學習效果很好
實戰：根據上面完成一個簡（la）單（ji）的聊天室應用（無界面，基於CMD）
這裏服務端可以單獨分出來可以單獨作爲一個工程打包爲jar，萬萬沒必要Springboot，但這裏懶得改了，就還是當後臺用吧hhh
首先，服務端需要展示的就是每個人所發出來的信息，和對上線人數下線人數進行實時的更新，之前更新是利用一個靜態變量,
但是這樣硬核了一點,這裏正好要用到羣發的功能,所以我們需要一個list來存放Channel,然後將這個list的size作爲在線人數就好了
羣發就遍歷這個數組,然後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 { //打印消息然後羣發 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(); } }
照樣，打包成jar，java -jar命令運行就行，哦對由於這裏是本地測試，所以yml文件中的IP應該換成127.0.0.1
接下來是客戶端，首先明確的就是用戶需要輸入信息，所以肯定要用到輸入函數，比如Scanner，另外，服務端需要知道每一個人的身份，這裏
簡單的用暱稱來代替，在發送的時候將名字也一併發過去，這樣就能簡單分辨是誰發的信息（其實這樣做主要是因爲沒來得及寫數據庫升級複雜一點的邏輯）
所以，在之前發信息的函數裏稍微處理一下就行，即增加信息輸入模塊
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();//輸入的內容 if (str.equals("exit")) break;//如果是exit則退出 future.channel().writeAndFlush(name+"-: "+str);//將名字和信息內容一起發過去 } future.channel().closeFuture().sync(); } finally { group.shutdownGracefully(); } }
之後把IP改成127.0.0.1就行，打包的時候，需要在pom文件中添加打包插件，特別注意的是要制定mainClass，不然運行時會報“沒有主清單屬性”
這裏貼上插件配置，這個插件其實對於所有Java程序都適用，因爲他會把依賴全帶上
<!-- java編譯插件 --> <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>
打包後之後就是運行了，效果大概是這樣.。。。。。。
哈哈哈哈有時間再完善一下