我正在使用netty 4.0.24.Final。
我需要以编程方式启动/停止Netty服务器。启动服务器时,线程在[
被阻塞f.channel().closeFuture().sync()
请提供一些提示,以帮助您正确地进行操作。下面是Main类调用的EchoServer。谢谢。
package nettytests;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
public class EchoServer {
private final int PORT = 8007;
private EventLoopGroup bossGroup;
private EventLoopGroup workerGroup;
public void start() throws Exception {
// Configure the server.
bossGroup = new NioEventLoopGroup(1);
workerGroup = new NioEventLoopGroup(1);
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 EchoServerHandler());
}
});
// Start the server.
ChannelFuture f = b.bind(PORT).sync();
// Wait until the server socket is closed. Thread gets blocked.
f.channel().closeFuture().sync();
} finally {
// Shut down all event loops to terminate all threads.
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
public void stop(){
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
package nettytests;
public class Main {
public static void main(String[] args) throws Exception {
EchoServer server = new EchoServer();
// start server
server.start();
// not called, because the thread is blocked above
server.stop();
}
}
UPDATE:我通过以下方式更改了EchoServer类。这个想法是在一个新线程中启动服务器,并保留到EventLoopGroups的链接。这是正确的方法吗?
package nettytests;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
/**
* Echoes back any received data from a client.
*/
public class EchoServer {
private final int PORT = 8007;
private EventLoopGroup bossGroup;
private EventLoopGroup workerGroup;
public void start() throws Exception {
new Thread(() -> {
// Configure the server.
bossGroup = new NioEventLoopGroup(1);
workerGroup = new NioEventLoopGroup(1);
Thread.currentThread().setName("ServerThread");
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 EchoServerHandler());
}
});
// 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();
}
}).start();
}
public void stop() throws InterruptedException {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
}
一种方法是制作类似的东西:
// once having an event in your handler (EchoServerHandler)
// Close the current channel
ctx.channel().close();
// Then close the parent channel (the one attached to the bind)
ctx.channel().parent().close();
这样做将导致以下结果:
// Wait until the server socket is closed. Thread gets blocked.
f.channel().closeFuture().sync();
不需要在主体上附加螺纹。现在的问题是:什么样的事件?这取决于您...在回显处理程序中可能是一条消息,称为“ shutdown”(关闭),它将被视为关闭的顺序,而不仅仅是“ quit”(退出),它将变成仅关闭客户端通道。可能是其他东西...
如果您不通过子处理程序(例如通过处理程序)处理从子通道的关闭,而是通过另一个进程(例如查找存在的停止文件),那么您需要一个额外的线程来等待此事件,然后直接执行一个channel.close()
,其中通道将是父通道(例如,从f.channel()
开始)...
还有许多其他解决方案。
我正在关注官方教程,并且遇到了相同的问题。教程具有相同的模式:
f.channel().closeFuture().sync();
...
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
也就是说,通道在组关闭之前已关闭。我将顺序更改为此:
bossGroup.shutdownGracefully().sync();
workerGroup.shutdownGracefully().sync();
f.channel().closeFuture().sync();
而且有效。这导致未锁定服务器的大致修改示例:
class Server
{
private ChannelFuture future;
private NioEventLoopGroup masterGroup;
private NioEventLoopGroup workerGroup;
Server(int networkPort)
{
masterGroup = new NioEventLoopGroup();
workerGroup = new NioEventLoopGroup();
try
{
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(masterGroup, workerGroup);
serverBootstrap.channel(NioServerSocketChannel.class);
serverBootstrap.option(ChannelOption.SO_BACKLOG,128);
serverBootstrap.childOption(ChannelOption.SO_KEEPALIVE,true);
serverBootstrap.childHandler(new ChannelInitializer<SocketChannel>()
{
@Override
protected void initChannel(SocketChannel ch)
{
ch.pipeline().addLast(new InboundHandler());
}
}).validate();
future = serverBootstrap.bind(networkPort).sync();
System.out.println("Started server on "+networkPort);
}
catch (Exception e)
{
e.printStackTrace();
shutdown();
}
}
void shutdown()
{
System.out.println("Stopping server");
try
{
masterGroup.shutdownGracefully().sync();
workerGroup.shutdownGracefully().sync();
future.channel().closeFuture().sync();
System.out.println("Server stopped");
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
}