我正在使用Netty 5.0。
我有一个补充的客户端引导程序，我从netty github获取了SecureChatClient.java示例。
Wenn我从客户端bootstrap发送消息到服务器它完全正常。当我尝试从服务器引导程序向客户端发送消息时（首先通过客户端成功启动连接/通道后），我得到一个java.lang.UnsupportedOperationException，但没有任何进一步的信息。从服务器向客户端发送消息是通过上面的代码完成的。
是仅用于接收的serverbootstrap吗？
如上所示，serverbootstrap不能将消息写回客户端吗？我的意思是，消息可以通过ChannelHandler从套接字进入ChannelPipeline，但只有ChannelHandler应该将响应写回ChannelPipeline并退出套接字。因此，在ServerBootstrap中，用户并不意味着能够从Pipeline外部沿ChannelPipeline发送消息。 （希望有意义）
或者我只是遗漏了什么？
我的代码如下：
// Ports.
int serverPort = 8080;
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast("MyMessageHandler", new MyMessageHandler());
}
})
.option(ChannelOption.SO_BACKLOG, 128)
.childOption(ChannelOption.SO_KEEPALIVE, true);
// Bind and start to accept incoming connections.
ChannelFuture f = b.bind(serverPort).sync();
Channel ch = f.channel();
System.out.println("Server: Running!");
// Read commands from the stdin.
ChannelFuture lastWriteFuture = null;
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
while(true)
{
String line = in.readLine();
if (line == null) break;
ByteBuf getOut = buffer(64);
getOut.writeBytes(line.getBytes());
// Sends the received line to the server.
lastWriteFuture = ch.writeAndFlush(getOut);
lastWriteFuture.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture cf) throws Exception {
if(cf.isSuccess()) {
System.out.println("CFListener: SUCCESS! YEAH! HELL! YEAH!");
} else {
System.out.println("CFListener: failure! FAILure! FAILURE!");
System.out.println(cf.cause());
}
}
});
}
// Wait until all messages are flushed before closing the channel.
if (lastWriteFuture != null) {
lastWriteFuture.sync();
}
// Wait until the server socket is closed.
// In this example, this does not happen, but you can do that to gracefully
// shut down your server.
f.channel().closeFuture().sync();
} catch (InterruptedException | UnsupportedOperationException e) {
e.printStackTrace();
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
我开始使用以下示例：https://github.com/netty/netty/tree/4.1/example/src/main/java/io/netty/example/securechat
我的问题是，在调用ch.writeAndFlush时出现以下异常：
java.lang.UnsupportedOperationException
at io.netty.channel.socket.nio.NioServerSocketChannel.filterOutboundMessage(NioServerSocketChannel.java:184)
at io.netty.channel.AbstractChannel$AbstractUnsafe.write(AbstractChannel.java:784)
at io.netty.channel.DefaultChannelPipeline$HeadContext.write(DefaultChannelPipeline.java:1278)
at io.netty.channel.ChannelHandlerInvokerUtil.invokeWriteNow(ChannelHandlerInvokerUtil.java:158)
at io.netty.channel.DefaultChannelHandlerInvoker$WriteTask.run(DefaultChannelHandlerInvoker.java:440)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:328)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
at io.netty.util.internal.chmv8.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1412)
at io.netty.util.internal.chmv8.ForkJoinTask.doExec(ForkJoinTask.java:280)
at io.netty.util.internal.chmv8.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:877)
at io.netty.util.internal.chmv8.ForkJoinPool.scan(ForkJoinPool.java:1706)
at io.netty.util.internal.chmv8.ForkJoinPool.runWorker(ForkJoinPool.java:1661)
at io.netty.util.internal.chmv8.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:126)
答案 0 :(得分：3)
您无法写入ServerChannel，只能连接到普通频道。由于这个原因，您对writeAndFlush的调用失败了。
要向每个客户端发送消息，您应该将每个客户端的通道存储在ChannelGroup内，并在其上调用writeAndFlush（）。
快速执行此操作的方法是向ServerBootstrap添加另一个处理程序，将传入连接放入ChannelGroup中，快速实现此操作：
// In your main:
ChannelGroup allChannels =
new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
// In your ChannelInitializer<SocketChannel>
ch.pipeline().addLast("grouper", new GlobalSendHandler());
// New class:
public class MyHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelActive(ChannelHandlerContext ctx) {
allChannels.add(ctx.channel());
super.channelActive(ctx);
}
}
然后我们可以调用以下内容向每个连接发送消息，这会返回ChannelGroupFuture而不是正常的ChannelFuture：
allChannels.writeAndFlush(getOut);
您的总代码看起来像上面的修补程序：
// Ports.
int serverPort = 8080;
ChannelGroup allChannels =
new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast("MyMessageHandler", new MyMessageHandler());
ch.pipeline().addLast("grouper", new GlobalSendHandler());
}
})
.option(ChannelOption.SO_BACKLOG, 128)
.childOption(ChannelOption.SO_KEEPALIVE, true);
// Bind and start to accept incoming connections.
ChannelFuture f = b.bind(serverPort).sync();
Channel ch = f.channel();
System.out.println("Server: Running!");
// Read commands from the stdin.
ChannelGroupFuture lastWriteFuture = null;
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
while(true)
{
String line = in.readLine();
if (line == null) break;
ByteBuf getOut = buffer(64);
getOut.writeBytes(line.getBytes());
// Sends the received line to the server.
lastWriteFuture = allChannels.writeAndFlush(getOut);
lastWriteFuture.addListener(new ChannelGroupFutureListener() {
@Override
public void operationComplete(ChannelGroupFuture cf) throws Exception {
if(cf.isSuccess()) {
System.out.println("CFListener: SUCCESS! YEAH! HELL! YEAH!");
} else {
System.out.println("CFListener: failure! FAILure! FAILURE!");
System.out.println(cf.cause());
}
}
});
}
// Wait until all messages are flushed before closing the channel.
if (lastWriteFuture != null) {
lastWriteFuture.sync();
}
// Wait until the server socket is closed.
// In this example, this does not happen, but you can do that to gracefully
// shut down your server.
f.channel().closeFuture().sync();
} catch (InterruptedException | UnsupportedOperationException e) {
e.printStackTrace();
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
答案 1 :(得分：1)
我认为Netty Server没有解码器，编码器。 如果你想发送字符串数据，
Appdata添加服务器的初始化程序！