Application Initialization and Termination
You often need to execute custom actions when the application starts and clean up everything when the application stops. This guide explains how to:
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Write a Quarkus application with a main method
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Write command mode applications that run a task and then terminate
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Be notified when the application starts
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Be notified when the application stops
Prerequisites
完成这个指南，你需要:
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大概15分钟
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编辑器
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安装JDK 11以上版本并正确配置了
JAVA_HOME -
Apache Maven 3.9.6
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如果你愿意的话，还可以选择使用Quarkus CLI
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如果你想构建原生可执行程序，可以选择安装Mandrel或者GraalVM，并正确配置(或者使用Docker在容器中进行构建)
Solution
We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.
Clone the Git repository: git clone https://github.com/quarkusio/quarkus-quickstarts.git, or download an archive.
The solution is located in the lifecycle-quickstart directory.
Creating the Maven project
First, we need a new project. Create a new project with the following command:
For Windows users:
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If using cmd, (don’t use backward slash
\and put everything on the same line) -
If using Powershell, wrap
-Dparameters in double quotes e.g."-DprojectArtifactId=lifecycle-quickstart"
It generates:
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the Maven structure
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example
Dockerfilefiles for bothnativeandjvmmodes -
the application configuration file
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.
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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;
}
}
}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:
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For Quarkus dev mode:
CLIquarkus dev -Dquarkus.args=cmd-argsMaven./mvnw quarkus:dev -Dquarkus.args=cmd-argsGradle./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.
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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.
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If a class is annotated with @Startup but with no scope annotation then @ApplicationScoped is added automatically.
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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
}
}Package and run the application
Run the application with:
quarkus dev./mvnw quarkus:dev./gradlew --console=plain quarkusDevThe logged message is printed. When the application is stopped, the second log message is printed.
As usual, the application can be packaged using:
quarkus build./mvnw install./gradlew buildand executed using java -jar target/quarkus-app/quarkus-run.jar.
You can also generate the native executable using:
quarkus build --native./mvnw install -Dnative./gradlew build -Dquarkus.package.type=nativeLaunch 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. This config property is a duration, and can be set using the standard java.time.Duration format, if only a number is specified it is interpreted as seconds.
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.
