netty实现TCP长连接

所用jar包

netty-all-4.1.30.Final.jar 密码：rzwe

NettyConfig.java，存放连接的客户端

import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.util.concurrent.GlobalEventExecutor;

public class NettyConfig {
    
    /**
     * 存储每一个客户端接入进来时的channel对象
     */
    public static ChannelGroup group = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
    
}

 

Server.java，netty配置信息

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.ServerSocketChannel;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;

public class Server {
    private int port;
    private ServerSocketChannel serverSocketChannel;
 
    public Server(int port){
        this.port = port;
        bind();
    }
    
    private void bind() {
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                //服务端要建立两个group，一个负责接收客户端的连接，一个负责处理数据传输
                //连接处理group
                EventLoopGroup boss = new NioEventLoopGroup();
                //事件处理group
                EventLoopGroup worker = new NioEventLoopGroup();
                ServerBootstrap bootstrap = new ServerBootstrap();
                // 绑定处理group
                bootstrap.group(boss, worker).channel(NioServerSocketChannel.class)
                        //保持连接数
                        .option(ChannelOption.SO_BACKLOG, 300)
                        //有数据立即发送
                        .option(ChannelOption.TCP_NODELAY, true)
                        //保持连接
                        .childOption(ChannelOption.SO_KEEPALIVE, true)
                        //处理新连接
                        .childHandler(new ChannelInitializer<SocketChannel>() {
                            @Override
                            protected void initChannel(SocketChannel sc) throws Exception {
                                // 增加任务处理
                                ChannelPipeline p = sc.pipeline();
                                p.addLast(
//                                        //使用了netty自带的编码器和解码器
//                                        new StringDecoder(),
//                                        new StringEncoder(),
                                        //心跳检测，读超时，写超时，读写超时
                                        //new IdleStateHandler(5, 0, 0, TimeUnit.SECONDS),
                                        //自定义的处理器
                                        new ServerHandler());
                            }
                        });
 
                //绑定端口，同步等待成功
                ChannelFuture future;
                try {
                    future = bootstrap.bind(port).sync();
                    if (future.isSuccess()) {
                        serverSocketChannel = (ServerSocketChannel) future.channel();
                        System.out.println("服务端启动成功，端口："+port);
                    } else {
                        System.out.println("服务端启动失败！");
                    }
                    
                    //等待服务监听端口关闭,就是由于这里会将线程阻塞，导致无法发送信息，所以我这里开了线程
                    future.channel().closeFuture().sync();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                finally {
                    //优雅地退出，释放线程池资源
                    boss.shutdownGracefully();
                    worker.shutdownGracefully();
                }
            }
        });
        thread.start();
    }
    
    public void sendMessage(Object msg){
        if(serverSocketChannel != null){
            serverSocketChannel.writeAndFlush(msg);
        }
    }
    
    public static void main(String[] args) {
        Server server = new Server(8088);
    }
}

 

ServerHandler.java，业务处理

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

public class ServerHandler extends ChannelInboundHandlerAdapter {    
      
    /**
     * 客户端与服务端创建连接的时候调用
     */
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("客户端与服务端连接开始...");
        NettyConfig.group.add(ctx.channel());
    }
 
    /**
     * 客户端与服务端断开连接时调用
     */
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("客户端与服务端连接关闭...");
        NettyConfig.group.remove(ctx.channel());
    }
 
    /**
     * 服务端接收客户端发送过来的数据结束之后调用
     */
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
        System.out.println("信息接收完毕...");
    }
 
    /**
     * 工程出现异常的时候调用
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
 
    /**
     * 服务端处理客户端websocket请求的核心方法，这里接收了客户端发来的信息
     */
    @Override
    public void channelRead(ChannelHandlerContext channelHandlerContext, Object info) throws Exception {
        System.out.println("接收到了："+info);
ByteBuf buf = (ByteBuf) info;
byte[] req = new byte[buf.readableBytes()];
buf.readBytes(req);
String body = new String(req, "UTF-8");
System.out.println("接收客户端数据:" + body);
ByteBuf pingMessage = Unpooled.buffer();
pingMessage.writeBytes(req);
channelHandlerContext.writeAndFlush(pingMessage);

        
        //服务端使用这个就能向 每个连接上来的客户端群发消息
        //NettyConfig.group.writeAndFlush(info);
//        Iterator<Channel> iterator = NettyConfig.group.iterator();
//        while(iterator.hasNext()){
//            //打印出所有客户端的远程地址
//            System.out.println((iterator.next()).remoteAddress());
//        }
    }
    
    
}

 

使用网络调试助手进行连接测试 下载地址

https://www.wanpishe.top/detail?blogId=fc62fce2-020a-4815-8388-0903e4a54e1f