Posts Tagged ‘服务端’

Netty4服务端心跳机制

星期六, 五月 17th, 2014 3,966 views

Netty4与Netty3.x的心跳机制略有不同,在Netty4中已经去掉了IdleStateAwareChannelHandler这个类,但IdleStateHandler依旧保留,只是心跳超时的触发事件的写法略有不同,Netty底层实现了一套类似信号和槽的事件通信机制。
这里且看实现。

首先是在 SocketChannel.pipeline 中注册 IdleStateHandler 进行心跳时间的定制:

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        // Configure the server.
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG, 100)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new ChannelInitializer<socketchannel>() {
                        @Override
                        public void initChannel(SocketChannel ch)
                                throws Exception {
                            ch.pipeline()
                                    .addLast(
                                            new LoggingHandler(LogLevel.INFO),
                                            new IdleStateHandler(30,0,0),// 心跳控制
                                            new ServerHandler());
                        }
                    });

            // Start the server.
            ChannelFuture f = b.bind(port).sync();

            // Wait until the server socket is closed.
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            // Shut down all event loops to terminate all threads.
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
</socketchannel>

这里要注意IdleStateHandler()要放在ServerHandler()的前面,否则心跳管理无法触发ServerHandler中的userEventTriggered()方法。

此时已经成功在服务器中创建了心跳控制器:
IdleStateHandler(int readerIdleTimeSeconds, int writerIdleTimeSeconds, int allIdleTimeSeconds)

Property Meaning
readerIdleTime an IdleStateEvent whose state is IdleState.READER_IDLE will be triggered when no read was performed for the specified period of time. Specify 0to disable.
writerIdleTime an IdleStateEvent whose state is IdleState.WRITER_IDLE will be triggered when no write was performed for the specified period of time. Specify 0 to disable.
allIdleTime an IdleStateEvent whose state is IdleState.ALL_IDLE will be triggered when neither read nor write was performed for the specified period of time. Specify 0 to disable.

(更多…)