我使用的是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
处被阻止 f.channel().closeFuture().sync()
请提供一些提示,如何正确操作。 下面是Main类调用的EchoServer。 感谢。
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();
}
}
更新 我用以下方式更改了EchoServer类。我们的想法是在新线程中启动服务器并保留指向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();
}
}
答案 0 :(得分:12)
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();
这样做将最终得到以下结论:
// Wait until the server socket is closed. Thread gets blocked.
f.channel().closeFuture().sync();
主要部分无需额外的线程。 现在的问题是:什么样的事件?这取决于你...可能在回显处理程序中作为“关闭”的消息将被视为关闭的顺序而不仅仅是“退出”,它将变为仅关闭客户端通道。可能是别的......
如果你没有从子通道处理关闭(通过你的处理程序),而是通过另一个进程(例如查找存在的停止文件),那么你需要一个额外的线程来等待这个事件然后直接制作一个channel.close()
,其中频道将是父节点(来自f.channel()
),例如......
存在许多其他解决方案。
答案 1 :(得分:0)
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();
它奏效了。这导致一个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();
}
}
}
答案 2 :(得分:0)
我刚刚关闭了事件循环组
bossGroup.shutdownGracefully().sync();
workerGroup.shutdownGracefully().sync();
效果很好,因为当我将请求发送到经过改造的代理服务器时,它说“无法连接”。