4.6. MicroProfile 指标开发

流程

1. 创建包含以下内容的类文件 HelloService.java ：

   package com.example.microprofile.metrics;
   
   public class HelloService {
       String createHelloMessage(String name){
           return "Hello" + name;
       }
   }

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2. 创建包含以下内容的类文件 HelloWorld.java ：

   package com.example.microprofile.metrics;
   
   import javax.inject.Inject;
   import javax.ws.rs.GET;
   import javax.ws.rs.Path;
   import javax.ws.rs.Produces;
   import org.eclipse.microprofile.metrics.annotation.Counted;
   
   @Path("/")
   public class HelloWorld {
   @Inject
       HelloService helloService;
   
   @GET
   @Path("/json")
       @Produces({ "application/json" })
       @Counted(name = "requestCount",
     		 absolute = true,
   description = "Number of times the getHelloWorldJSON was requested")
       public String getHelloWorldJSON() {
           return "{\"result\":\"" + helloService.createHelloMessage("World") + "\"}";
       }
   }

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3. 更新 pom.xml 文件，使其包含以下依赖项：

   <dependency>
       <groupId>org.eclipse.microprofile.metrics</groupId>
       <artifactId>microprofile-metrics-api</artifactId>
       <scope>provided</scope>
   </dependency>

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4. 使用以下 Maven 命令构建应用程序：

   $ mvn clean install wildfly:deploy

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5. 测试指标：

   1. 在 CLI 中运行以下命令：

      $ curl -v http://localhost:9990/metrics |  grep request_count | grep helloworld-rs-metrics

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      预期输出：

      jboss_undertow_request_count_total{deployment="helloworld-rs-metrics.war",servlet="org.jboss.as.quickstarts.rshelloworld.JAXActivator",subdeployment="helloworld-rs-metrics.war",microprofile_scope="vendor"} 0.0

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   2. 在浏览器中，导航到 URL http://localhost:8080/helloworld-rs/rest/json

   3. 在 CLI 中重新执行以下命令：

      $ curl -v http://localhost:9990/metrics |  grep request_count | grep helloworld-rs-metrics

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      预期输出：

      jboss_undertow_request_count_total{deployment="helloworld-rs-metrics.war",servlet="org.jboss.as.quickstarts.rshelloworld.JAXActivator",subdeployment="helloworld-rs-metrics.war",microprofile_scope="vendor"} 1.0

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