adisky / hello-quarkus

title	linkTitle	weight	type
Hello World - Java (Quarkus)	Java (Quarkus)	1	docs

A simple JAX-RS REST API application that is written in Java and uses Quarkus.

This samples uses Docker to build locally. The app reads in a TARGET env variable and then prints "Hello World: ${TARGET}!". If a value for TARGET is not specified, the "NOT SPECIFIED" default value is used.

Before you begin

You must meet the following requirements to run this sample:

• An installed version of the following tools:
  • Java SE 8 or later JDK
  • Maven

Getting the code

You can either clone a working copy of the sample code from the repository, or following the steps in the Recreating the sample code to walk through the steps of updating all the files.

Recreating the sample code

Use the following steps to obtain an incomplete copy of the sample code for which you update and create the necessary build and configuration files:

1. From the console, create a new empty web project using the Maven archetype commands:

   mvn io.quarkus:quarkus-maven-plugin:0.13.3:create \
    -DprojectGroupId=com.redhat.developer.demos \
    -DprojectArtifactId=helloworld-java-quarkus \
    -DclassName="com.redhat.developer.demos.GreetingResource" \
    -Dpath="/"

2. Update the GreetingResource class in src/main/java/com/redhat/developer/demos/GreetingResource.java to handle the "/" mapping and also add a @ConfigProperty field to provide the TARGET environment variable:

   package com.redhat.developer.demos;
   
   import javax.ws.rs.GET;
   import javax.ws.rs.Path;
   import javax.ws.rs.Produces;
   import javax.ws.rs.core.MediaType;
   import org.eclipse.microprofile.config.inject.ConfigProperty;
   
   @Path("/")
   public class GreeterResource {
     @ConfigProperty(name = "TARGET", defaultValue="World")
     String target;
   
     @GET
     @Produces(MediaType.TEXT_PLAIN)
     public String greet() {
       return "Hello " + target + "!";
     }
   }

3. Update src/main/resources/application.properties to configuration the application to default to port 8080, but allow the port to be overriden by the PORT environmental variable:

   # Configuration file
   # key = value
   
   quarkus.http.port=${PORT:8080}
   

4. Update src/test/java/com/redhat/developer/demos/GreetingResourceTest.java test to reflect the change:

   package com.redhat.developer.demos;
   
   import io.quarkus.test.junit.QuarkusTest;
   import org.junit.jupiter.api.Test;
   
   import static io.restassured.RestAssured.given;
   import static org.hamcrest.CoreMatchers.is;
   
   @QuarkusTest
   public class GreetingResourceTest {
   
     @Test
     public void testHelloEndpoint() {
         given()
           .when().get("/")
           .then()
             .statusCode(200)
             .body(is("Hello World!"));
     }
   }

5. Remove src/main/resources/META-INF/resources/index.html file since it's unncessary for this example.

   rm src/main/resources/META-INF/resources/index.html

6. Remove .dockerignore file since it's unncessary for this example.

   rm .dockerignore

7. In your project directory, create a file named Dockerfile and copy the code block below into it.

   FROM quay.io/rhdevelopers/quarkus-java-builder:graal-1.0.0-rc15 as builder
   COPY . /project
   WORKDIR /project
   # uncomment this to set the MAVEN_MIRROR_URL of your choice, to make faster builds
   # ARG MAVEN_MIRROR_URL=<your-maven-mirror-url>
   # e.g.
   #ARG MAVEN_MIRROR_URL=http://192.168.64.1:8081/nexus/content/groups/public
   
   RUN /usr/local/bin/entrypoint-run.sh mvn -DskipTests clean package
   
   FROM fabric8/java-jboss-openjdk8-jdk:1.5.4
   USER jboss
   ENV JAVA_APP_DIR=/deployments
   
   COPY --from=builder /project/target/lib/* /deployments/lib/
   COPY --from=builder /project/target/*-runner.jar /deployments/app.jar
   
   ENTRYPOINT [ "/deployments/run-java.sh" ]
   

   If you want to build Quarkus native image, then copy the following code block in to file called Dockerfile.native

   FROM quay.io/rhdevelopers/quarkus-java-builder:graal-1.0.0-rc15 as builder
   COPY . /project
   # uncomment this to set the MAVEN_MIRROR_URL of your choice, to make faster builds
   # ARG MAVEN_MIRROR_URL=<your-maven-mirror-url>
   # e.g.
   # ARG MAVEN_MIRROR_URL=http://192.168.64.1:8081/nexus/content/groups/public
   
   RUN /usr/local/bin/entrypoint-run.sh mvn -DskipTests clean package -Pnative
   
   FROM registry.fedoraproject.org/fedora-minimal
   
   COPY --from=builder /project/target/helloworld-java-quarkus-runner /app
   
   ENTRYPOINT [ "/app" ]
   

Locally testing your sample

1. Run the application locally:

   ./mvnw compile quarkus:dev

   Go to http://localhost:8080/ to see your Hello World! message.