Netty4(一)NioEventLoopGroup

先看默认构造方法

public NioEventLoopGroup() {

this(0);

}

有参构造方法

public NioEventLoopGroup(int nThreads) {

this(nThreads, (Executor)null);

}

public NioEventLoopGroup(int nThreads, Executor executor) {

//获得了Selector提供器

this(nThreads, executor, SelectorProvider.provider());

}

public NioEventLoopGroup(int nThreads, Executor executor, SelectorProvider selectorProvider) {

this(nThreads, executor, selectorProvider, DefaultSelectStrategyFactory.INSTANCE);

}

public NioEventLoopGroup(int nThreads, Executor executor, SelectorProvider selectorProvider, SelectStrategyFactory selectStrategyFactory) {

super(nThreads, executor, new Object[]{selectorProvider, selectStrategyFactory, 

//拒绝策略

RejectedExecutionHandlers.reject()});

}

//这个就是上面那个默认拒绝策略

private static final RejectedExecutionHandler REJECT = new RejectedExecutionHandler() {

public void rejected(Runnable task, SingleThreadEventExecutor executor) {

throw new RejectedExecutionException();

}

};

接着就是这个构造方法

最后到MultithreadEventExecutorGroup

protected MultithreadEventLoopGroup(int nThreads, Executor executor, Object... args) {

super(nThreads == 0 ? DEFAULT_EVENT_LOOP_THREADS : nThreads, executor, args);

}

这个就是默认线程池个数最小1个最大内核数的2倍

private static final int DEFAULT_EVENT_LOOP_THREADS = Math.max(1, SystemPropertyUtil.getInt("io.netty.eventLoopThreads", NettyRuntime.availableProcessors() * 2));

executor = new ThreadPerTaskExecutor(this.newDefaultThreadFactory());

this.children = new EventExecutor[nThreads];

this.children[i] = this.newChild((Executor)executor, args);