如何以编程方式在Dropwizard中获取应用程序端口

Question

我正在使用dropwizard 0.7.1版。它被配置为使用“随机”（短暂？）端口（server.applicationConnectors.port = 0）。我想知道启动后真正使用的端口，但是我找不到任何信息如何做到这一点。

Answer 1

您可以从生命周期侦听器获取serverStarted回调来解决这个问题。

@Override 
public void run(ExampleConfiguration configuration, Environment environment) throws Exception { 
    environment.lifecycle().addServerLifecycleListener(new ServerLifecycleListener() { 
    @Override 
    public void serverStarted(Server server) { 
     for (Connector connector : server.getConnectors()) { 
     if (connector instanceof ServerConnector) { 
      ServerConnector serverConnector = (ServerConnector) connector; 
      System.out.println(serverConnector.getName() + " " + serverConnector.getLocalPort()); 
      // Do something useful with serverConnector.getLocalPort() 
     } 
     } 
    } 
    }); 
} 

Answer 2

我发现这种方法在Dropwizard中同时适用于Simple和Default服务器配置。

public void run(ExampleConfiguration configuration, Environment environment) throws Exception { 

    Stream<ConnectorFactory> connectors = configuration.getServerFactory() instanceof DefaultServerFactory 
      ? ((DefaultServerFactory)configuration.getServerFactory()).getApplicationConnectors().stream() 
      : Stream.of((SimpleServerFactory)configuration.getServerFactory()).map(SimpleServerFactory::getConnector); 

    int port = connectors.filter(connector -> connector.getClass().isAssignableFrom(HttpConnectorFactory.class)) 
      .map(connector -> (HttpConnectorFactory) connector) 
      .mapToInt(HttpConnectorFactory::getPort) 
      .findFirst(); 
      .orElseThrow(IllegalStateException::new); 
}