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あいつの日誌です。

getting started dropwizard 0.7.0

Java dropwizard

this article is copied from Getting Started | Dropwizard

Setting Up Maven

% mkdir dropwizard && cd dropwizard
% mvn archetype:create -DgroupId=com.example -DartifactId=myapp
% cd myapp

% git init
% git add .
% git commit -m 'initial commit' 

check it

% mvn package

pom.xml

add a dropwizard.version:

% git diff pom.xml
diff --git a/pom.xml b/pom.xml
index ecbd708..41a3631 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,6 +12,7 @@

   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <dropwizard.version>0.7.0</dropwizard.version>
   </properties>

   <dependencies>
% git add pom.xml
% git commit -m 'add a dropwizard.version'

add dropwizard-core library as a dependency:

% git diff
--- a/pom.xml
+++ b/pom.xml
@@ -22,5 +22,10 @@
       <version>3.8.1</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>io.dropwizard</groupId>
+      <artifactId>dropwizard-core</artifactId>
+      <version>${dropwizard.version}</version>
+    </dependency>
   </dependencies>
 </project>
% git add pom.xml
% git commit -m 'add dropwizard-core library as a dependency'

check it.

% mvn package 

[INFO] Building jar: /Users/okamuuu/dropwizard/myapp/target/myapp-1.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:19 min
[INFO] Finished at: 2014-11-06T12:36:38+09:00
[INFO] Final Memory: 17M/154M
[INFO] ------------------------------------------------------------------------

you can see 'BUILD SUCCESS' and finished Setting Up Maven.

Creating A Configuration Class

create src/main/java/com/example/helloworld/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;
    }
}
% git add src/main/java/com/example/helloworld/HelloWorldConfiguration.java
% git commit -m 'add HelloWorldConfiguration'

create myapp.yml

template: Hello, %s!
defaultName: Stranger
% git add myapp.yml
% git commit -m 'myapp.yml'

check it.

% mvn package
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

you can see 'BUILD SUCCESS' and finished Creating A Configuration Class

Creating An Application Class

create src/main/java/com/example/helloworld/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) {
        // nothing to do yet
    }

}
% git add src/main/java/com/example/helloworld/HelloWorldApplication.java
% git commit -m 'add HelloWorldApplication'

check it

% mvn package

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

you can see 'BUILD SUCCESS' and finished Creating An Application Class

Creating A Representation Class

create src/main/java/com/example/helloworld/core/Saying.java:

package com.example.helloworld.core;

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;
    }
}
% git add src/main/java/com/example/helloworld/core/Saying.java
% git commit -m 'add core/Saying'

check it

% mvn package

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

you can see 'BUILD SUCCESS' and finished Creating A Representation Class

Creating A Resource Class

create src/main/java/com/example/helloworld/resources/HelloWorldResource.java:

package com.example.helloworld.resources;

import com.example.helloworld.core.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);
    }
}
% git add src/main/java/com/example/helloworld/resources/HelloWorldResource.java
% git commit -m 'add resorces/HelloWorldResource'

check it

% mvn package

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

you can see 'BUILD SUCCESS' and finished Creating A Resource Class

Registering A Resource

edit src/main/java/com/example/helloworld/HelloWorldApplication.java:

% git diff src/main/java/com/example/helloworld/HelloWorldApplication.java
diff --git a/src/main/java/com/example/helloworld/HelloWorldApplication.java b/src/main/java/com/example/helloworld/HelloWorldApplication.java
index c9601f9..e6f65cf 100644
--- a/src/main/java/com/example/helloworld/HelloWorldApplication.java
+++ b/src/main/java/com/example/helloworld/HelloWorldApplication.java
@@ -3,7 +3,7 @@ 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.resources.HelloWorldResource;
 //import com.example.helloworld.health.TemplateHealthCheck;
 
 public class HelloWorldApplication extends Application<HelloWorldConfiguration> {
@@ -24,7 +24,11 @@ public class HelloWorldApplication extends Application<HelloWorldConfiguration>
     @Override
     public void run(HelloWorldConfiguration configuration,
                     Environment environment) {
-        // nothing to do yet
+        final HelloWorldResource resource = new HelloWorldResource(
+            configuration.getTemplate(),
+            configuration.getDefaultName()
+        );
+        environment.jersey().register(resource);
     }
 
 }
% git add src/main/java/com/example/helloworld/HelloWorldApplication.java
% git commit -m "add resource instance to the application's Jersey environment"
% mvn package

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

you can see 'BUILD SUCCESS' and finished Registering A Resource

Creating A Health Check

create src/main/java/com/example/helloworld/health/TemplateHealthCheck.java:

package com.example.helloworld.health;

import com.codahale.metrics.health.HealthCheck;

public class TemplateHealthCheck extends HealthCheck {
    private final String template;

    public TemplateHealthCheck(String template) {
        this.template = template;
    }

    @Override
    protected Result check() throws Exception {
        final String saying = String.format(template, "TEST");
        if (!saying.contains("TEST")) {
            return Result.unhealthy("template doesn't include a name");
        }
        return Result.healthy();
    }
}
% git add src/main/java/com/example/helloworld/health/TemplateHealthCheck.java
% git commit -m "add TemplateHealthCheck"
% mvn package

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

you can see 'BUILD SUCCESS' and finished Creating A Health Check

Adding A Health Check

edit src/main/java/com/example/helloworld/HelloWorldApplication.java:

% git diff src/main/java/com/example/helloworld/HelloWorldApplication.java
diff --git a/src/main/java/com/example/helloworld/HelloWorldApplication.java b/src/main/java/com/example/helloworld/HelloWorldApplication.java
index e6f65cf..cdfce9b 100644
--- a/src/main/java/com/example/helloworld/HelloWorldApplication.java
+++ b/src/main/java/com/example/helloworld/HelloWorldApplication.java
@@ -4,7 +4,7 @@ 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;
+import com.example.helloworld.health.TemplateHealthCheck;
 
 public class HelloWorldApplication extends Application<HelloWorldConfiguration> {
     public static void main(String[] args) throws Exception {
@@ -28,6 +28,9 @@ public class HelloWorldApplication extends Application<HelloWorldConfiguration>
             configuration.getTemplate(),
             configuration.getDefaultName()
         );
+        final TemplateHealthCheck healthCheck =
+            new TemplateHealthCheck(configuration.getTemplate());
+        environment.healthChecks().register("template", healthCheck);
         environment.jersey().register(resource);
     }
% git add src/main/java/com/example/helloworld/HelloWorldApplication.java
% git commit -m "add healthcheck instance to the Environment"

check it.

% mvn package

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

you can see 'BUILD SUCCESS' and finished Adding A Health Check.

Now we’re almost ready to go!

Building Fat JARs

edit pom.xml:

% git diff pom.xml
diff --git a/pom.xml b/pom.xml
index ad0cf1c..322e8dd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -28,4 +28,43 @@
       <version>${dropwizard.version}</version>
     </dependency>
   </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-shade-plugin</artifactId>
+        <version>1.6</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>
+    </plugins>
+  </build>
 </project>
% git add pom.xml
% git commit -m 'add maven-shade plugins'

Versioning Your JARs

edit pom.xml again

% git diff pom.xml
diff --git a/pom.xml b/pom.xml
index 322e8dd..d4b67a8 100644
--- a/pom.xml
+++ b/pom.xml
@@ -65,6 +65,18 @@
             </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>
% git add pom.xml
% git commit -m 'add maven-jar-plugin'

Running Your Application

% java -jar target/myapp-1.0-SNAPSHOT.jar server myapp.yml
% open http://localhost:8080/hello-world
% open http://localhost:8081/