您好,登錄后才能下訂單哦!
這篇文章主要為大家展示了“Netty客戶端接入流程N(yùn)ioSocketChannel怎么創(chuàng)建”,內(nèi)容簡(jiǎn)而易懂,條理清晰,希望能夠幫助大家解決疑惑,下面讓小編帶領(lǐng)大家一起研究并學(xué)習(xí)一下“Netty客戶端接入流程N(yùn)ioSocketChannel怎么創(chuàng)建”這篇文章吧。
public void read() { //必須是NioEventLoop方法調(diào)用的, 不能通過(guò)外部線程調(diào)用 assert eventLoop().inEventLoop(); //服務(wù)端channel的config final ChannelConfig config = config(); //服務(wù)端channel的pipeline final ChannelPipeline pipeline = pipeline(); //處理服務(wù)端接入的速率 final RecvByteBufAllocator.Handle allocHandle = unsafe().recvBufAllocHandle(); //設(shè)置配置 allocHandle.reset(config); boolean closed = false; Throwable exception = null; try { try { do { //創(chuàng)建jdk底層的channel //readBuf用于臨時(shí)承載讀到鏈接 int localRead = doReadMessages(readBuf); if (localRead == 0) { break; } if (localRead < 0) { closed = true; break; } //分配器將讀到的鏈接進(jìn)行計(jì)數(shù) allocHandle.incMessagesRead(localRead); //連接數(shù)是否超過(guò)最大值 } while (allocHandle.continueReading()); } catch (Throwable t) { exception = t; } int size = readBuf.size(); //遍歷每一條客戶端連接 for (int i = 0; i < size; i ++) { readPending = false; //傳遞事件, 將創(chuàng)建NioSokectChannel進(jìn)行傳遞 //最終會(huì)調(diào)用ServerBootstrap的內(nèi)部類(lèi)ServerBootstrapAcceptor的channelRead()方法 pipeline.fireChannelRead(readBuf.get(i)); } readBuf.clear(); allocHandle.readComplete(); pipeline.fireChannelReadComplete(); //代碼省略 } finally { //代碼省略 } }
我們繼續(xù)剖析int localRead = doReadMessages(readBuf)這一部分邏輯
private final List<Object> readBuf = new ArrayList<Object>();
這里只是簡(jiǎn)單的定義了一個(gè)ArrayList, doReadMessages(readBuf)方法就是將讀到的鏈接放在這個(gè)list中, 因?yàn)檫@里是NioServerSocketChannel所以這走到了NioServerSocketChannel的doReadMessage()方法
跟到doReadMessage()方法中:
protected int doReadMessages(List<Object> buf) throws Exception { //根據(jù)當(dāng)前jdk底層的serverSocketChannel拿到j(luò)dk底層channel SocketChannel ch = javaChannel().accept(); try { if (ch != null) { //封裝成一個(gè)NioSokectChannel扔到buf中 buf.add(new NioSocketChannel(this, ch)); return 1; } } catch (Throwable t) { //代碼省略 } return 0; }
首先根據(jù)jdk的ServerSocketChannel拿到j(luò)dk的Channel, 熟悉Nio的小伙伴應(yīng)該不會(huì)陌生
封裝成一個(gè)NioSokectChannel扔到Readbuf中
這里的NioSocketChannel是對(duì)jdk底層的SocketChannel的包裝, 我們看到其構(gòu)造方法傳入兩個(gè)參數(shù), this代表當(dāng)前NioServerSocketChannel, ch代表jdk的SocketChannel
我們跟到NioSocketChannel的構(gòu)造方法中:
public NioSocketChannel(Channel parent, SocketChannel socket) { super(parent, socket); config = new NioSocketChannelConfig(this, socket.socket()); }
這里看到調(diào)用了父類(lèi)構(gòu)造方法, 傳入兩個(gè)參數(shù), parent代表創(chuàng)建自身channel的, NioServerSocketChannel, socket代表jdk底層的socketChannel
protected AbstractNioByteChannel(Channel parent, SelectableChannel ch) { super(parent, ch, SelectionKey.OP_READ); }
其中SelectionKey.OP_READ代表其監(jiān)聽(tīng)事件是讀事件
繼續(xù)跟父類(lèi)的構(gòu)造方法:
protected AbstractNioChannel(Channel parent, SelectableChannel ch, int readInterestOp) { super(parent); this.ch = ch; this.readInterestOp = readInterestOp; try { //設(shè)置為非阻塞 ch.configureBlocking(false); } catch (IOException e) { //代碼省略 } }
這里初始化了自身成員變量ch, 就是jdk底層的SocketChannel, 并初始化了自身的監(jiān)聽(tīng)事件readInterestOp, 也就是讀事件
ch.configureBlocking(false)這一步熟悉nio的小伙伴也不陌生, 就是將jdk的SocketChannel設(shè)置為非阻塞
我們繼續(xù)跟到父類(lèi)構(gòu)造方法中:
protected AbstractChannel(Channel parent) { this.parent = parent; id = newId(); unsafe = newUnsafe(); pipeline = newChannelPipeline(); }
這里初始化parent, 也就是創(chuàng)建自身的NioServerSocketChannel, 并為自身創(chuàng)建了唯一id
初始化unsafe, 我們跟到newUnsafe()方法中
由于此方法是NioEventLoop調(diào)用的, 所以會(huì)走到其父類(lèi)AbstractNioByteChannel的newUnsafe()
跟到newUnsafe()中:
protected AbstractNioUnsafe newUnsafe() { return new NioByteUnsafe(); }
這里創(chuàng)建了NioByteUnsafe對(duì)象, 所以NioSocketChannel對(duì)應(yīng)的unsafe是NioByteUnsafe
繼續(xù)往下跟, 我們看到其初始化了pipeline, 有關(guān)pipline的知識(shí), 我們會(huì)在下一章節(jié)中講到
回到NioSocketChannel中的構(gòu)造方法:
public NioSocketChannel(Channel parent, SocketChannel socket) { super(parent, socket); config = new NioSocketChannelConfig(this, socket.socket()); }
同NioServerSocketChannel一樣, 這里也初始化了一個(gè)Config屬性, 傳入兩個(gè)參數(shù), 當(dāng)前NioSocketChannel自身和jdk的底層SocketChannel的socket對(duì)象
private NioSocketChannelConfig(NioSocketChannel channel, Socket javaSocket) { super(channel, javaSocket); }
同樣, 這個(gè)類(lèi)是NioSocketChannel的內(nèi)部類(lèi)
繼續(xù)跟父類(lèi)構(gòu)造方法:
public DefaultSocketChannelConfig(SocketChannel channel, Socket javaSocket) { super(channel); if (javaSocket == null) { throw new NullPointerException("javaSocket"); } //保存當(dāng)前javaSocket this.javaSocket = javaSocket; //是否禁止Nagle算法 if (PlatformDependent.canEnableTcpNoDelayByDefault()) { try { setTcpNoDelay(true); } catch (Exception e) { } } }
這里保存了SocketChannel的socket對(duì)象, 并且默認(rèn)的情況禁止了Nagle算法, 有關(guān)Nagle, 感興趣的同學(xué)可以學(xué)習(xí)下相關(guān)知識(shí)
繼續(xù)跟到父類(lèi)構(gòu)造方法中:
public DefaultChannelConfig(Channel channel) { this(channel, new AdaptiveRecvByteBufAllocator()); }
又跟到到了我們熟悉的部分了, 也就是說(shuō), 無(wú)論NioServerSocketChannel和NioSocketChannel, 最后都會(huì)初始化DefaultChannelConfig, 并創(chuàng)建可變ByteBuf分配器, 我們之前小節(jié)對(duì)此做過(guò)詳細(xì)剖析這里不再贅述。
以上是“Netty客戶端接入流程N(yùn)ioSocketChannel怎么創(chuàng)建”這篇文章的所有內(nèi)容,感謝各位的閱讀!相信大家都有了一定的了解,希望分享的內(nèi)容對(duì)大家有所幫助,如果還想學(xué)習(xí)更多知識(shí),歡迎關(guān)注億速云行業(yè)資訊頻道!
免責(zé)聲明:本站發(fā)布的內(nèi)容(圖片、視頻和文字)以原創(chuàng)、轉(zhuǎn)載和分享為主,文章觀點(diǎn)不代表本網(wǎng)站立場(chǎng),如果涉及侵權(quán)請(qǐng)聯(lián)系站長(zhǎng)郵箱:is@yisu.com進(jìn)行舉報(bào),并提供相關(guān)證據(jù),一經(jīng)查實(shí),將立刻刪除涉嫌侵權(quán)內(nèi)容。