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Inicialização e encerramento da aplicação

You often need to execute custom actions when the application starts and clean up everything when the application stops. This guide explains how to:

  • Write a Quarkus application with a main method

  • Write command mode applications that run a task and then terminate

  • Be notified when the application starts

  • Be notified when the application stops

Pré-requisitos

Para concluir este guia, você precisa:

  • Cerca de 15 minutos

  • Um IDE

  • JDK 17+ installed with JAVA_HOME configured appropriately

  • Apache Maven 3.9.6

  • Opcionalmente, o Quarkus CLI se você quiser usá-lo

  • Opcionalmente, Mandrel ou GraalVM instalado e configurado apropriadamente se você quiser criar um executável nativo (ou Docker se você usar uma compilação de contêiner nativo)

Solução

Recomendamos que siga as instruções nas seções seguintes e crie a aplicação passo a passo. No entanto, você pode ir diretamente para o exemplo completo.

Clone o repositório Git: git clone https://github.com/quarkusio/quarkus-quickstarts.git, ou baixe um arquivo.

The solution is located in the lifecycle-quickstart directory.

Criar o projeto Maven

Primeiro, precisamos de um novo projeto. Crie um novo projeto com o seguinte comando:

CLI
quarkus create app org.acme:lifecycle-quickstart \
    --no-code
cd lifecycle-quickstart

Para criar um projeto Gradle, adicione a opção --gradle ou --gradle-kotlin-dsl.

Para obter mais informações sobre como instalar e usar a CLI do Quarkus, consulte o guia Quarkus CLI.

Maven
mvn io.quarkus.platform:quarkus-maven-plugin:3.11.1:create \
    -DprojectGroupId=org.acme \
    -DprojectArtifactId=lifecycle-quickstart \
    -DnoCode
cd lifecycle-quickstart

Para criar um projeto Gradle, adicione a opção '-DbuildTool=gradle' ou '-DbuildTool=gradle-kotlin-dsl'.

Para usuários do Windows:

  • Se estiver usando cmd, (não use barra invertida '\' e coloque tudo na mesma linha)

  • Se estiver usando o Powershell, envolva os parâmetros '-D' entre aspas duplas, por exemplo, '"-DprojectArtifactId=lifecycle-quickstart"'

It generates:

  • a estrutura Maven

  • exemplo de arquivos Dockerfile para os modos nativo e jvm

  • o arquivo de configuração da aplicação

The main method

By default, Quarkus will automatically generate a main method, that will bootstrap Quarkus and then just wait for shutdown to be initiated. Let’s provide our own main method:

package com.acme;

import io.quarkus.runtime.annotations.QuarkusMain;
import io.quarkus.runtime.Quarkus;

@QuarkusMain  (1)
public class Main {

    public static void main(String ... args) {
        System.out.println("Running main method");
        Quarkus.run(args); (2)
    }
}
1 This annotation tells Quarkus to use this as the main method, unless it is overridden in the config
2 This launches Quarkus

This main class will bootstrap Quarkus and run it until it stops. This is no different to the automatically generated main class, but has the advantage that you can just launch it directly from the IDE without needing to run a Maven or Gradle command.

It is not recommenced to do any business logic in this main method, as Quarkus has not been set up yet, and Quarkus may run in a different ClassLoader. If you want to perform logic on startup use an io.quarkus.runtime.QuarkusApplication as described below.

If we want to actually perform business logic on startup (or write applications that complete a task and then exit) we need to supply a io.quarkus.runtime.QuarkusApplication class to the run method. After Quarkus has been started the run method of the application will be invoked. When this method returns the Quarkus application will exit.

If you want to perform logic on startup you should call Quarkus.waitForExit(), this method will wait until a shutdown is requested (either from an external signal like when you press Ctrl+C or because a thread has called Quarkus.asyncExit()).

An example of what this looks like is below:

package com.acme;

import io.quarkus.runtime.Quarkus;
import io.quarkus.runtime.QuarkusApplication;
import io.quarkus.runtime.annotations.QuarkusMain;

@QuarkusMain
public class Main {
    public static void main(String... args) {
        Quarkus.run(MyApp.class, args);
    }

    public static class MyApp implements QuarkusApplication {

        @Override
        public int run(String... args) throws Exception {
            System.out.println("Do startup logic here");
            Quarkus.waitForExit();
            return 0;
        }
    }
}

Quarkus.run also provides a version that allows the code to handle errors. For example:

package com.acme;

import io.quarkus.runtime.Quarkus;
import io.quarkus.runtime.QuarkusApplication;
import io.quarkus.runtime.annotations.QuarkusMain;

@QuarkusMain
public class Main {
    public static void main(String... args) {
        Quarkus.run(MyApp.class,
        (exitCode, exception) -> {
            // do whatever
        },
        args);
    }

    public static class MyApp implements QuarkusApplication {

        @Override
        public int run(String... args) throws Exception {
            System.out.println("Do startup logic here");
            Quarkus.waitForExit();
            return 0;
        }
    }
}

Injecting the command line arguments

It is possible to inject the arguments that were passed in on the command line:

@Inject
@CommandLineArguments
String[] args;

Command line arguments can be passed to the application through the -D flag with the property quarkus.args:

  • For Quarkus dev mode:

    CLI
    quarkus dev -Dquarkus.args=cmd-args
    Maven
    ./mvnw quarkus:dev -Dquarkus.args=cmd-args
    Gradle
    ./gradlew --console=plain quarkusDev -Dquarkus.args=cmd-args
  • For a runner jar: java -Dquarkus.args=<cmd-args> -jar target/quarkus-app/quarkus-run.jar

  • For a native executable: ./target/lifecycle-quickstart-1.0-SNAPSHOT-runner -Dquarkus.args=<cmd-args>

Listening for startup and shutdown events

Create a new class named AppLifecycleBean (or pick another name) in the org.acme.lifecycle package, and copy the following content:

package org.acme.lifecycle;

import jakarta.enterprise.context.ApplicationScoped;
import jakarta.enterprise.event.Observes;

import io.quarkus.runtime.ShutdownEvent;
import io.quarkus.runtime.StartupEvent;
import org.jboss.logging.Logger;

@ApplicationScoped
public class AppLifecycleBean {

    private static final Logger LOGGER = Logger.getLogger("ListenerBean");

    void onStart(@Observes StartupEvent ev) {               (1)
        LOGGER.info("The application is starting...");
    }

    void onStop(@Observes ShutdownEvent ev) {               (2)
        LOGGER.info("The application is stopping...");
    }

}
1 Method called when the application is starting
2 Method called when the application is terminating
The events are also called in dev mode between each redeployment.
The methods can access injected beans. Check the AppLifecycleBean.java class for details.

What is the difference from @Initialized(ApplicationScoped.class) and @Destroyed(ApplicationScoped.class)

In the JVM mode, there is no real difference, except that StartupEvent is always fired after @Initialized(ApplicationScoped.class) and ShutdownEvent is fired before @Destroyed(ApplicationScoped.class). For a native executable build, however, @Initialized(ApplicationScoped.class) is fired as part of the native build process, whereas StartupEvent is fired when the native image is executed. See Three Phases of Bootstrap and Quarkus Philosophy for more details.

In CDI applications, an event with qualifier @Initialized(ApplicationScoped.class) is fired when the application context is initialized. See the spec for more info.

Using @Startup to initialize a CDI bean at application startup

A bean represented by a class, producer method or field annotated with @Startup is initialized at application startup:

package org.acme.lifecycle;

import io.quarkus.runtime.Startup;
import jakarta.enterprise.context.ApplicationScoped;

@Startup (1)
@ApplicationScoped
public class EagerAppBean {

   private final String name;

   EagerAppBean(NameGenerator generator) { (2)
     this.name = generator.createName();
   }
}
1 For each bean annotated with @Startup a synthetic observer of StartupEvent is generated. The default priority is used.
2 The bean constructor is called when the application starts and the resulting contextual instance is stored in the application context.
@Dependent beans are destroyed immediately afterwards to follow the behavior of observers declared on @Dependent beans.
If a class is annotated with @Startup but with no scope annotation then @ApplicationScoped is added automatically.

The @Startup annotation can be also declared on a non-static non-producer no-args method:

package org.acme.lifecycle;

import io.quarkus.runtime.Startup;
import jakarta.enterprise.context.ApplicationScoped;

@ApplicationScoped
public class EagerAppBean {

   @Startup
   void init() { (1)
     doSomeCoolInit();
   }
}
1 The bean is created and the init() method is invoked upon the contextual instance when the application starts.

Using @Shutdown to execute a business method of a CDI bean during application shutdown

The @io.quarkus.runtime.Shutdown annotation is used to mark a business method of a CDI bean that should be executed during application shutdown. The annotated method must be non-private and non-static and declare no arguments. The behavior is similar to a declaration of a ShutdownEvent observer. The following examples are functionally equivalent.

import io.quarkus.runtime.Shutdown;
import io.quarkus.runtime.ShutdownEvent;
import jakarta.enterprise.context.ApplicationScoped;

@ApplicationScoped
class Bean1 {
   void onShutdown(@Observes ShutdownEvent event) {
      // place the logic here
   }
}

@ApplicationScoped
class Bean2 {

   @Shutdown
   void shutdown() {
      // place the logic here
   }
}

Empacote e execute a aplicação

Execute a aplicação com:

CLI
quarkus dev
Maven
./mvnw quarkus:dev
Gradle
./gradlew --console=plain quarkusDev

The logged message is printed. When the application is stopped, the second log message is printed.

Como de costume, a aplicação pode ser empacotada utilizando:

CLI
quarkus build
Maven
./mvnw install
Gradle
./gradlew build

and executed using java -jar target/quarkus-app/quarkus-run.jar.

You can also generate the native executable using:

CLI
quarkus build --native
Maven
./mvnw install -Dnative
Gradle
./gradlew build -Dquarkus.native.enabled=true

Launch Modes

Quarkus has 3 different launch modes, NORMAL (i.e. production), DEVELOPMENT and TEST. If you are running quarkus:dev then the mode will be DEVELOPMENT, if you are running a JUnit test it will be TEST, otherwise it will be NORMAL.

Your application can get the launch mode by injecting the io.quarkus.runtime.LaunchMode enum into a CDI bean, or by invoking the static method io.quarkus.runtime.LaunchMode.current().

Graceful Shutdown

Quarkus includes support for graceful shutdown, this allows Quarkus to wait for running requests to finish, up till a set timeout. By default, this is disabled, however you can configure this by setting the quarkus.shutdown.timeout config property. When this is set shutdown will not happen until all running requests have completed, or until this timeout has elapsed.

Extensions that accept requests need to add support for this on an individual basis. At the moment only the HTTP extension supports this, so shutdown may still happen when messaging requests are active.

Quarkus supports a delay time, where the application instance still responds to requests, but the readiness probe fails. This gives the infrastructure time to recognize that the instance is shutting down and stop routing traffic to the instance. This feature can be enabled by setting the build-time property quarkus.shutdown.delay-enabled to true. The delay can then be configured by setting the runtime property quarkus.shutdown.delay. It is not set by default, thus no delay is applied.

To write duration values, use the standard java.time.Duration format. See the Duration#parse() javadoc for more information.

Você também pode usar um formato simplificado, começando com um número:

  • Se o valor for apenas um número, ele representará o tempo em segundos.

  • Se o valor for um número seguido de 'ms', ele representa o tempo em milissegundos.

Em outros casos, o formato simplificado é traduzido para o formato 'java.time.Duration' para análise:

  • Se o valor for um número seguido de 'h', 'm' ou 's', ele é prefixado com 'PT'.

  • Se o valor for um número seguido de 'd', ele é prefixado com 'P'.

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