如何使用一个 Bootstrap 连接到 Netty 中的多个服务器

Question

如果我每次连接到远程服务器时都创建（新）引导程序，我不知道是否存在性能问题。所以我想使用一个引导实例连接到多个服务器。我的代码如下：

Bootstrap b = new Bootstrap();
b.group(new NioEventLoopGroup()).handler(new TestHandler()).channel(NioSocketChannel.class)
        .option(ChannelOption.AUTO_READ, false);
ChannelFutureListener listener = new ChannelFutureListener() {
    @Override
    public void operationComplete(ChannelFuture future) throws Exception {
        if (future.isSuccess()) {
            // connection complete start to read first data
            System.out.println("connection established + channel: " + future.channel());
        } else {
            // Close the connection if the connection attempt has failed.
            System.out.println("connection failed");
        }
    }
};

String[] urls = { "www.google.com", "www.stackoverflow.com", "www.yahoo.com" };
for (String s : urls) {
    b = b.clone();
    b.remoteAddress(s, 80);
    b.connect().addListener(listener);
}
System.in.read();

不幸的是，它崩溃了：

connection established + channel: [id: 0x5df86eec, /192.168.126.136:60414 => www.google.com/173.194.127.209:80]
Exception in thread "main" java.lang.IllegalStateException: channel not registered to an event loop
    at io.netty.channel.AbstractChannel.eventLoop(AbstractChannel.java:107)
    at io.netty.channel.nio.AbstractNioChannel.eventLoop(AbstractNioChannel.java:102)
    at io.netty.channel.nio.AbstractNioChannel.eventLoop(AbstractNioChannel.java:41)
    at io.netty.channel.CompleteChannelFuture.executor(CompleteChannelFuture.java:48)
    at io.netty.util.concurrent.CompleteFuture.addListener(CompleteFuture.java:49)
    at io.netty.channel.CompleteChannelFuture.addListener(CompleteChannelFuture.java:56)
    at Test3.main(Test3.java:41)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)

我认为我以错误的方式使用引导程序。如果是这样，我应该每次都创建一个全新的引导程序吗？

至少，我应该使用相同的 NioEventLoopGroup，对吧？

Answer 1

好吧，这是我的错，我忘记添加 ChannelInitializer。将其更改为以下代码：

b.group(new NioEventLoopGroup()).handler(new ChannelInitializer<NioSocketChannel>() {

            @Override
            protected void initChannel(NioSocketChannel ch) throws Exception {
                ch.pipeline().addLast(new TestHandler());
            }
        })