[java] [maven] [dropwizard] helloworld dropwizard-0-9-2 from scratch

This exercise attempt to recreate the dropwizard helloworld app using PowerShell console, notepad, Java and Maven.

Note: the following notes is based on windows powershell environment

[1] make new project directory

mkdir dropwizard-helloworld

[2] change directory to the project directory

cd dropwizard-helloworld

[3] create pom file

<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/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.ciena.tim</groupId> <artifactId>dropwizard-helloworld</artifactId> <packaging>jar</packaging> <version>1.0-SNAPSHOT</version> <name>dropwizard-helloworld</name> <properties> <dropwizard.version>0.9.2</dropwizard.version> </properties> <dependencies> <dependency> <groupId>io.dropwizard</groupId> <artifactId>dropwizard-core</artifactId> <version>${dropwizard.version}</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <version>2.3</version> <configuration> <createDependencyReducedPom>true</createDependencyReducedPom> <filters> <filter> <artifact>*:*</artifact> <excludes> <exclude>META-INF/*.SF</exclude> <exclude>META-INF/*.DSA</exclude> <exclude>META-INF/*.RSA</exclude> </excludes> </filter> </filters> </configuration> <executions> <execution> <phase>package</phase> <goals> <goal>shade</goal> </goals> <configuration> <transformers> <transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/> <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer"> <mainClass>com.example.helloworld.HelloWorldApplication</mainClass> </transformer> </transformers> </configuration> </execution> </executions> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <version>2.4</version> <configuration> <archive> <manifest> <addDefaultImplementationEntries>true</addDefaultImplementationEntries> </manifest> </archive> </configuration> </plugin> </plugins> </build> </project>

[4] create source code directory

mkdir src/main

[5] change directory to source code directory

cd src/main

[6] create package directory

mkdir com/example/helloworld

[7] change directory to package directory

cd com/example/helloworld

[8] create java file (HelloWorldCofiguration.java)

notepad HelloWorldConfiguration.java
package com.example.helloworld; import io.dropwizard.Configuration; import com.fasterxml.jackson.annotation.JsonProperty; import org.hibernate.validator.constraints.NotEmpty; public class HelloWorldConfiguration extends Configuration { @NotEmpty private String template; @NotEmpty private String defaultName = "Stranger"; @JsonProperty public String getTemplate() { return template; } @JsonProperty public void setTemplate(String template) { this.template = template; } @JsonProperty public String getDefaultName() { return defaultName; } @JsonProperty public void setDefaultName(String name) { this.defaultName = name; } }

[9] create java file (HelloWorldApplication.java)

notepad HelloWorldApplication.java
package com.example.helloworld; import io.dropwizard.Application; import io.dropwizard.setup.Bootstrap; import io.dropwizard.setup.Environment; import com.example.helloworld.resources.HelloWorldResource; //import com.example.helloworld.health.TemplateHealthCheck; public class HelloWorldApplication extends Application<HelloWorldConfiguration> { public static void main(String[] args) throws Exception { new HelloWorldApplication().run(args); } @Override public String getName() { return "hello-world"; } @Override public void initialize(Bootstrap<HelloWorldConfiguration> bootstrap) { // nothing to do yet } @Override public void run(HelloWorldConfiguration configuration, Environment environment) { final HelloWorldResource resource = new HelloWorldResource( configuration.getTemplate(), configuration.getDefaultName() ); environment.jersey().register(resource); } }

[10] create java file in sub folder (resources/HelloWorldResource.java)

mkdir resources cd resources notepad HelloWorldResource
package com.example.helloworld.resources; import com.example.helloworld.api.Saying; import com.google.common.base.Optional; import com.codahale.metrics.annotation.Timed; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.Produces; import javax.ws.rs.QueryParam; import javax.ws.rs.core.MediaType; import java.util.concurrent.atomic.AtomicLong; @Path("/hello-world") @Produces(MediaType.APPLICATION_JSON) public class HelloWorldResource { private final String template; private final String defaultName; private final AtomicLong counter; public HelloWorldResource(String template, String defaultName) { this.template = template; this.defaultName = defaultName; this.counter = new AtomicLong(); } @GET @Timed public Saying sayHello(@QueryParam("name") Optional<String> name) { final String value = String.format(template, name.or(defaultName)); return new Saying(counter.incrementAndGet(), value); } }

[11] create java file in another sub folder (api/Saying.java)

mkdir api cd api notepad Saying.java
package com.example.helloworld.api; import com.fasterxml.jackson.annotation.JsonProperty; import org.hibernate.validator.constraints.Length; public class Saying { private long id; @Length(max = 3) private String content; public Saying() { // Jackson deserialization } public Saying(long id, String content) { this.id = id; this.content = content; } @JsonProperty public long getId() { return id; } @JsonProperty public String getContent() { return content; } }

create yml file at project root (hello-world.yml)

template: Hello, %s! defaultName: Stranger

compile package

mvn clean install

run jar file

java -jar target/dropwizard-helloworld-1.0-SNAPSHOT.jar server hello-world.yml

ref: https://github.com/timmackinnon/dropwizard-helloworld/tree/master