Micronaut: bind all the query parameters to a POJO

Using the exploded operator (?pojo*) in the URI template, we can bind all the query parameters to a POJO.

 

Example

@Get(value = "/even-numbers{?numbersMeta*}", produces = MediaType.TEXT_PLAIN)
public String evenNumbers(@Valid @Nullable NumbersMeta numbersMeta) {

}

Find the below working application.

 

Step 1: Create new maven project ‘micronaut-bind-query-params-to-pojo’.

 

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-bind-query-params-to-pojo</artifactId>
	<version>0.1</version>
	<packaging>jar</packaging>

	<parent>
		<groupId>io.micronaut</groupId>
		<artifactId>micronaut-parent</artifactId>
		<version>3.7.4</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 NumbersMeta class.

 

NumbersMeta.java

package com.sample.app.model;

import io.micronaut.core.annotation.Introspected;

@Introspected
public class NumbersMeta {
	private Integer from;

	private Integer to;

	public Integer getFrom() {
		return from;
	}

	public void setFrom(Integer from) {
		this.from = from;
	}

	public Integer getTo() {
		return to;
	}

	public void setTo(Integer to) {
		this.to = to;
	}

}

Step 4: Define HelloController class.

 

HelloController.java

package com.sample.app.controller;

import java.util.StringJoiner;

import javax.validation.Valid;

import com.sample.app.model.NumbersMeta;

import io.micronaut.core.annotation.Nullable;
import io.micronaut.http.MediaType;
import io.micronaut.http.annotation.Controller;
import io.micronaut.http.annotation.Get;

@Controller("/hello")
public class HelloController {

	@Get(value = "/even-numbers{?numbersMeta*}", produces = MediaType.TEXT_PLAIN)
	public String evenNumbers(@Valid @Nullable NumbersMeta numbersMeta) {

		Integer from = numbersMeta.getFrom();
		Integer to = numbersMeta.getTo();

		if (from == null || from < 0) {
			from = 0;
		}

		if (to == null || to < 0) {
			to = from + 10;
		}

		final StringJoiner stringJoiner = new StringJoiner(",");

		for (int i = from; i < to; i += 2) {
			stringJoiner.add("" + i);
		}

		return stringJoiner.toString();
	}

}

Step 5: 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);

		// Use this if you want the beans to be initialized eagerly
		/*
		 * Micronaut.build(args) .eagerInitSingletons(true) .mainClass(App.class)
		 * .start();
		 */
	}
}

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-bind-query-params-to-pojo-0.1.jar’ in project target folder.

$ls ./target/
classes
generated-sources
generated-test-sources
maven-archiver
maven-status
micronaut-bind-query-params-to-pojo-0.1.jar
original-micronaut-bind-query-params-to-pojo-0.1.jar
test-classes

Execute below command to run the application.

java -jar ./target/micronaut-bind-query-params-to-pojo-0.1.jar

Run below command to test the application.

curl --location --request GET 'http://localhost:8080/hello/even-numbers?from=10&to=30'

$curl --location --request GET 'http://localhost:8080/hello/even-numbers?from=10&to=30'
10,12,14,16,18,20,22,24,26,28

You can download the application from this link.

Previous                                                    Next                                                    Home