I'm trying to setup a simple UDP server using Netty following the example here but using Spring for wiring dependencies.
My Spring config class:
@Configuration
@ComponentScan("com.example.netty")
public class SpringConfig {
@Value("${netty.nThreads}")
private int nThreads;
@Autowired
private MyHandlerA myHandlerA;
@Autowired
private MyHandlerB myHandlerB;
@Bean(name = "bootstrap")
public Bootstrap bootstrap() {
Bootstrap b = new Bootstrap();
b.group(group())
.channel(NioDatagramChannel.class)
.handler(new ChannelInitializer<DatagramChannel>() {
@Override
protected void initChannel(DatagramChannel ch) throws Exception {
ch.pipeline().addLast(myHandlerA, myHandlerB);
}
});
return b;
}
@Bean(name = "group", destroyMethod = "shutdownGracefully")
public NioEventLoopGroup group() {
return new NioEventLoopGroup(nThreads);
}
@Bean
public static PropertySourcesPlaceholderConfigurer propertyPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
}
My server class:
@Component
public class MyUDPServer {
@Autowired
private Bootstrap bootstrap;
@Value("${host}")
private String host;
@Value("${port}")
private int port;
@PostConstruct
public void start() throws Exception {
bootstrap.bind(host, port).sync().channel().closeFuture().await();
/* Never reached since the main thread blocks due to the call to await() */
}
}
During the blocking call to await(), I don't see my application listening on the specified interface. I've tried to run the sample (setting up the server directly from the main function) and it works. I didn't find examples for setting up a UDP server using Netty and Spring.
Thanks, Mickael
EDIT:
In order to avoid blocking the Main thread (which is used for Spring configuration), I've created a new thread as follows:
@Component
public class MyUDPServer extends Thread {
@Autowired
private Bootstrap bootstrap;
@Value("${host}")
private String host;
@Value("${port}")
private int port;
public MyUDPServer() {
setName("UDP Server");
}
@PostConstruct
@Override
public synchronized void start() {
super.start();
}
@Override
public void run() {
try {
bootstrap.bind(host, port).sync().channel().closeFuture().await();
} catch (InterruptedException e) {
} finally {
bootstrap.group().shutdownGracefully();
}
}
@PreDestroy
@Override
public void interrupt() {
super.interrupt();
}
}
I can see the new thread is blocked waiting for Channel close (as in the example). The Main thread can continue Spring configuration. However, it still doesn't work.
