Oracle Helidon访问rest示例

1，创建一个Helidon MP项目

mvn archetype:generate -DinteractiveMode=false \
    -DarchetypeGroupId=io.helidon.archetypes \
    -DarchetypeArtifactId=helidon-quickstart-mp \
    -DarchetypeVersion=1.0.0 \
    -DgroupId=io.helidon.guides \
    -DartifactId=mp-restful-webservice \
    -Dpackage=io.helidon.guides.mp.restfulwebservice

2，修改pom.xml，在<dependencies>标签里追加unirest-java依赖

		<dependency>
			<groupId>com.mashape.unirest</groupId>
			<artifactId>unirest-java</artifactId>
			<version>1.4.9</version>
		</dependency>

3，更新maven，取得unirest-java jar包。使用Eclipse工具时，在项目上点击右键，然后依次点击[Maven]->[Update Project]，最后点击[OK]按钮。

4，修改src/main/resources/META-INF/microprofile-config.properties，最近rest api访问的url和api key。请事先在openweathermap.org网站上注册并获得api key。

app.api.baseUrl=https://api.openweathermap.org/data/2.5
app.api.key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

5，新建QuoteApplication.java类。

package io.helidon.guides.mp.restfulwebservice;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import javax.enterprise.context.ApplicationScoped;
import javax.ws.rs.ApplicationPath;
import javax.ws.rs.core.Application;

@ApplicationScoped
@ApplicationPath("/")
public class QuoteApplication extends Application {

	@Override
	public Set<Class<?>> getClasses() {
		Set<Class<?>> set = new HashSet<>();
		set.add(QuoteResource.class);
		return Collections.unmodifiableSet(set);
	}

}

6，新建QuoteResource.java类。

package io.helidon.guides.mp.restfulwebservice;

import javax.enterprise.context.RequestScoped;
import javax.inject.Inject;
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;

import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.JsonNode;
import com.mashape.unirest.http.Unirest;
import com.mashape.unirest.http.exceptions.UnirestException;

@Path("/quote")
@RequestScoped
public class QuoteResource {

	private static String apiBaseUrl = null;
	private static String apiKey = null;

	@Inject
	public QuoteResource(@ConfigProperty(name = "app.api.baseUrl") final String apiBaseUrl,
			@ConfigProperty(name = "app.api.key") final String apiKey) {
		if (this.apiBaseUrl == null) {
			this.apiBaseUrl = apiBaseUrl;
		}

		if (this.apiKey == null) {
			this.apiKey = apiKey;
		}
	}

	@SuppressWarnings("checkstyle:designforextension")
	@Path("/random")
	@GET
	@Produces(MediaType.APPLICATION_JSON)
	public String getRandomQuote() throws UnirestException {
		String url = apiBaseUrl + "/weather?q=London&appid=" + apiKey;
		HttpResponse<JsonNode> quote = Unirest.get(url).asJson();
		return quote.getBody().toString();
	}

}

7，运行项目，右键点击Main.java并运行。日志如下

2019.03.14 10:34:01 INFO org.jboss.weld.Version Thread[main,5,main]: WELD-000900: 3.0.3 (Final)
2019.03.14 10:34:01 INFO org.jboss.weld.Bootstrap Thread[main,5,main]: WELD-ENV-000020: Using jandex for bean discovery
2019.03.14 10:34:02 INFO org.jboss.weld.Bootstrap Thread[main,5,main]: WELD-000101: Transactional services not available. Injection of @Inject UserTransaction not available. Transactional observers will be invoked synchronously.
2019.03.14 10:34:02 INFO org.jboss.weld.Event Thread[main,5,main]: WELD-000411: Observer method [BackedAnnotatedMethod] private org.glassfish.jersey.ext.cdi1x.internal.CdiComponentProvider.processAnnotatedType(@Observes ProcessAnnotatedType) receives events for all annotated types. Consider restricting events using @WithAnnotations or a generic type with bounds.
2019.03.14 10:34:02 WARN org.jboss.weld.Bootstrap Thread[main,5,main]: WELD-000146: BeforeBeanDiscovery.addAnnotatedType(AnnotatedType<?>) used for class org.glassfish.jersey.ext.cdi1x.internal.CdiComponentProvider$JaxRsParamProducer is deprecated from CDI 1.1!
2019.03.14 10:34:04 INFO org.jboss.weld.Bootstrap Thread[main,5,main]: WELD-ENV-002003: Weld SE container bd1d650f-592e-400a-a2ff-b168e1f05b35 initialized
2019.03.14 10:34:04 INFO io.helidon.microprofile.security.SecurityMpService Thread[main,5,main]: Security extension for microprofile is enabled, yet security configuration is missing from config (requires providers configuration at key security.providers). Security will not have any valid provider.
2019.03.14 10:34:05 INFO io.helidon.webserver.NettyWebServer Thread[nioEventLoopGroup-2-1,10,main]: Channel '@default' started: [id: 0x9f97ffc3, L:/0:0:0:0:0:0:0:0:8080]
2019.03.14 10:34:05 INFO io.helidon.microprofile.server.ServerImpl Thread[nioEventLoopGroup-2-1,10,main]: Server started on http://localhost:8080 (and all other host addresses) in 134 milliseconds.
http://localhost:8080/greet

8，访问

curl http://localhost:8080/quote/random

结果

{"dt":1552530790,"coord":{"lon":-0.13,"lat":51.51},"visibility":10000,"weather":[{"icon":"10n","description":"light rain","main":"Rain","id":500}],"name":"London","cod":200,"main":{"temp":280.69,"temp_min":279.82,"humidity":81,"pressure":1010,"temp_max":281.48},"clouds":{"all":92},"id":2643743,"sys":{"country":"GB","sunrise":1552544248,"sunset":1552586578,"id":1502,"type":1,"message":0.0169},"base":"stations","wind":{"deg":250,"speed":6.7}}

结尾！