Chapter 4. Injecting configuration values into your Quarkus application

Procedure

1. Review the GreetingResource.java file and make sure it includes the following import statements:

   package org.acme.config;
   
   import java.util.Optional;
   import javax.inject.Inject;

2. Create a file GreetingConfiguration.java in the src/main/java/org/acme/config directory.

3. Add the @ConfigProperties and @Optional imports to the GreetingConfiguration.java file:

   package org.acme.config;
   
   import io.quarkus.arc.config.ConfigProperties;
   import java.util.Optional;

4. Create a GreetingConfiguration class for the greeting properties in your GreetingConfiguration.java file:

   @ConfigProperties(prefix = "greeting") 

   1

   
   public class GreetingConfiguration {
   
       private String message;
       private String suffix = "!"; 

   2

   
       private Optional<String> name;
   
       public String getMessage() {
           return message;
       }
   
       public void setMessage(String message) {
           this.message = message;
       }
   
       public String getSuffix() {
           return suffix;
       }
   
       public void setSuffix(String suffix) {
           this.suffix = suffix;
       }
   
       public Optional<String> getName() {
           return name;
       }
   
       public void setName(Optional<String> name) {
           this.name = name;
       }
   }

   1

   prefix is optional. If you do not set the prefix, it will be determined by the class name. In this example, it will be greeting.

   2

   If greeting.suffix is not set, ! will be the default value.

5. Inject the attribute into the GreetingResource class using the context and dependency injection (CDI) @Inject annotation:

   @Inject
   GreetingConfiguration greetingConfiguration;

6. To compile your application in development mode, enter the following command from the project directory:

   ./mvnw quarkus:dev

   Important

   If you do not provide values for the class properties, the application fails and a javax.enterprise.inject.spi.DeploymentException is thrown indicating a missing value. This does not apply to Optional fields and fields with a default value.

Procedure

1. Review the GreetingConfiguration.java file and make sure it includes the following import statements:

   import io.quarkus.arc.config.ConfigProperties;
   import java.util.Optional;
   import java.util.List;

2. Add the configuration in your GreetingConfiguration.java file using the @ConfigProperties annotation.

   The following example shows the configuration of the GreetingConfiguration class and its properties:

   @ConfigProperties(prefix = "greeting")
   public class GreetingConfiguration {
   
       public String message;
       public String suffix = "!";
       public Optional<String> name;
   }

3. Add a nested class configuration similar to the following example:

   @ConfigProperties(prefix = "greeting")
   public class GreetingConfiguration {
   
       public String message;
       public String suffix = "!";
       public Optional<String> name;
       public HiddenConfig hidden;
   
       public static class HiddenConfig {
           public Integer prizeAmount;
           public List<String> recipients;
       }
   }

   This example shows a nested class HiddenConfig. The name of the field, in this case hidden, determines the name of the properties bound to the object.

4. Add the equivalent configuration properties to your application.properties file.

   The following example shows the value of properties for the GreetingConfiguration and HiddenConfig classes:

   greeting.message = hello
   greeting.name = quarkus
   greeting.hidden.prize-amount=10
   greeting.hidden.recipients=Jane,John

5. To compile your application in development mode, enter the following command from the project directory:

   ./mvnw quarkus:dev

Procedure

1. Review the GreetingConfiguration.java file and make sure it includes the following import statements:

   package org.acme.config;
   
   import io.quarkus.arc.config.ConfigProperties;
   import org.eclipse.microprofile.config.inject.ConfigProperty;
   import java.util.Optional;

2. Add a GreetingConfiguration class as an interface to your GreetingConfiguration.java file:

   @ConfigProperties(prefix = "greeting")
   public interface GreetingConfiguration {
   
       @ConfigProperty(name = "message") 

   1

   
       String message();
   
       @ConfigProperty(defaultValue = "!")
       String getSuffix(); 

   2

   
   
       Optional<String> getName(); 

   3

   
   }

   1

   You must set the @ConfigProperty annotation because the name of the configuration property does not follow the getter method naming conventions.

   2

   In this example, name was not set so the corresponding property will be greeting.suffix.

   3

   You do not need to specify the @ConfigProperty annotation because the method name follows the getter method naming conventions (greeting.name being the corresponding property) and no default value is needed.

3. To compile your application in development mode, enter the following command from the project directory:

   ./mvnw quarkus:dev

   Important

   If you do not provide a value for an interface field, the application fails and an javax.enterprise.inject.spi.DeploymentException is thrown indicating a missing value. This does not apply to Optional fields and fields with a default value.