Simple controller snippet in Micronaut looks like below.
@Controller("/welcome")
public class WelcomeController {
@Get(produces = MediaType.TEXT_PLAIN)
public String index() {
return "Welcome to Micronaut app!!!!";
}
}
a. The class is defined as a controller with the @Controller annotation mapped to the path /welcome
b. The method responds to a GET requests to /welcome and returns a response with a text/plain content type
To run the application in embedding server, use below snippet.
public class App {
public static void main(String[] args) {
Micronaut.run(App.class);
}
}
Find the below working application.
Step 1: Create new maven project ‘micronaut-rest-hello-world’.
Step 2: Update pom.xml with maven dependencies.
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.sample.app</groupId>
<artifactId>micronaut-rest-hello-world</artifactId>
<version>0.1</version>
<packaging>jar</packaging>
<parent>
<groupId>io.micronaut</groupId>
<artifactId>micronaut-parent</artifactId>
<version>3.7.3</version>
</parent>
<properties>
<packaging>jar</packaging>
<jdk.version>11</jdk.version>
<release.version>11</release.version>
<micronaut.version>3.7.3</micronaut.version>
<micronaut.runtime>netty</micronaut.runtime>
<exec.mainClass>com.sample.app.App</exec.mainClass>
</properties>
<repositories>
<repository>
<id>central</id>
<url>https://repo.maven.apache.org/maven2</url>
</repository>
</repositories>
<dependencies>
<dependency>
<groupId>io.micronaut</groupId>
<artifactId>micronaut-inject</artifactId>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>io.micronaut</groupId>
<artifactId>micronaut-validation</artifactId>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>io.micronaut</groupId>
<artifactId>micronaut-http-client</artifactId>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>io.micronaut</groupId>
<artifactId>micronaut-http-server-netty</artifactId>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>io.micronaut</groupId>
<artifactId>micronaut-jackson-databind</artifactId>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>jakarta.annotation</groupId>
<artifactId>jakarta.annotation-api</artifactId>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>io.micronaut.test</groupId>
<artifactId>micronaut-test-junit5</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>io.micronaut.build</groupId>
<artifactId>micronaut-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<!-- Uncomment to enable incremental compilation -->
<!-- <useIncrementalCompilation>false</useIncrementalCompilation> -->
<annotationProcessorPaths
combine.children="append">
<path>
<groupId>io.micronaut</groupId>
<artifactId>micronaut-http-validation</artifactId>
<version>${micronaut.version}</version>
</path>
</annotationProcessorPaths>
</configuration>
</plugin>
</plugins>
</build>
</project>
Step 3: Define WelcomeController class.
WelcomeController.java
package com.sample.app.controller;
import io.micronaut.http.MediaType;
import io.micronaut.http.annotation.Controller;
import io.micronaut.http.annotation.Get;
@Controller("/welcome")
public class WelcomeController {
@Get(produces = MediaType.TEXT_PLAIN)
public String index() {
return "Welcome to Micronaut app!!!!";
}
}
Step 4: Define main application class.
App.java
package com.sample.app;
import io.micronaut.runtime.Micronaut;
public class App {
public static void main(String[] args) {
Micronaut.run(App.class);
}
}
Total project structure looks like below.
Build the project using mvn package command.
Navigate to the folder where pom.xml is located and execute the command ‘mvn package’.
Upon command successful execution, you can see the jar file ‘micronaut-rest-hello-world-0.1.jar’ in project target folder.
$ls ./target/
classes
generated-sources
generated-test-sources
maven-archiver
maven-status
micronaut-rest-hello-world-0.1.jar
original-micronaut-rest-hello-world-0.1.jar
test-classes
Execute below command to run the application.
java -jar ./target/micronaut-rest-hello-world-0.1.jar
Once the application started, open the url ‘http://localhost:8080/welcome’ in browser, you will see below kind of screen.
You can download the application from this link.
Let’s learn, how to test the hello-world application in the next post.
No comments:
Post a Comment