<dependency>
  <groupId>io.micrometer</groupId>
  <artifactId>micrometer-registry-prometheus</artifactId>
</dependency>
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

management:
  endpoints:
    web:
      exposure:
        include: prometheus,health,metrics
  metrics:
    export:
      prometheus:
        enabled: true

scrape_configs:
  - job_name: 'order-service'
    metrics_path: /actuator/prometheus
    static_configs:
      - targets: ['order-service-host:8080']

import io.micrometer.core.instrument.Counter;
import io.micrometer.core.instrument.Timer;
import io.micrometer.core.instrument.MeterRegistry;
import org.springframework.stereotype.Component;

@Component
public class OrderMetrics {
    private final Counter orderSuccessCounter;
    private final Counter orderFailureCounter;
    private final Timer orderProcessTimer;

    public OrderMetrics(MeterRegistry registry) {
        this.orderSuccessCounter = Counter.builder("order_success_total")
            .description("成功下單總次數(shù)")
            .register(registry);
        this.orderFailureCounter = Counter.builder("order_failure_total")
            .description("下單失敗總次數(shù)")
            .register(registry);
        this.orderProcessTimer = Timer.builder("order_process_duration")
            .description("訂單處理時長")
            .publishPercentileHistogram()
            .register(registry);
    }

    public void recordSuccess() {
        orderSuccessCounter.increment();
    }

    public void recordFailure() {
        orderFailureCounter.increment();
    }

    public Timer.Sample startTimer() {
        return Timer.start(orderProcessTimer.getId().getRegistry());
    }
}

@Service
public class OrderService {

    private final OrderMetrics metrics;

    public OrderService(OrderMetrics metrics) {
        this.metrics = metrics;
    }

    public void createOrder(OrderRequest req) {
        Timer.Sample sample = metrics.startTimer();
        try {
            // 業(yè)務(wù)邏輯：保存訂單、調(diào)用支付等
            // ...
            metrics.recordSuccess();
        } catch (Exception e) {
            metrics.recordFailure();
            throw e;
        } finally {
            sample.stop(metrics.orderProcessTimer);
        }
    }
}