深入探讨Spring Boot中服务层的必要性：无业务逻辑场景下的架构考量

// src/main/java/com/example/demo/dto/DumpRequest.java
package com.example.demo.dto;

import javax.validation.constraints.NotBlank; // 假设使用JSR 303/349 校验

public class DumpRequest {
    @NotBlank(message = "数据内容不能为空")
    private String data;
    private String topic; // 可选，如果API允许指定topic

    // Getters and Setters
    public String getData() {
        return data;
    }

    public void setData(String data) {
        this.data = data;
    }

    public String getTopic() {
        return topic;
    }

    public void setTopic(String topic) {
        this.topic = topic;
    }
}

// src/main/java/com/example/demo/service/DumpService.java
package com.example.demo.service;

import com.example.demo.dto.DumpRequest;

public interface DumpService {
    void dumpDataToKafka(DumpRequest request);
}

// src/main/java/com/example/demo/service/impl/DumpServiceImpl.java
package com.example.demo.service.impl;

import com.example.demo.dto.DumpRequest;
import com.example.demo.service.DumpService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Service;

@Service
public class DumpServiceImpl implements DumpService {

    private static final Logger log = LoggerFactory.getLogger(DumpServiceImpl.class);

    private final KafkaTemplate<String, String> kafkaTemplate;

    @Value("${kafka.default.topic:default-dump-topic}") // 从配置中读取默认topic
    private String defaultTopic;

    public DumpServiceImpl(KafkaTemplate<String, String> kafkaTemplate) {
        this.kafkaTemplate = kafkaTemplate;
    }

    @Override
    public void dumpDataToKafka(DumpRequest request) {
        // 1. 数据校验 (即使是简单的，也可以在此处进行，例如检查data是否为空，尽管DTO已处理)
        if (request == null || request.getData() == null || request.getData().isEmpty()) {
            log.warn("Attempted to dump empty or null data.");
            throw new IllegalArgumentException("Data to dump cannot be empty.");
        }

        String targetTopic = request.getTopic() != null && !request.getTopic().isEmpty()
                             ? request.getTopic()
                             : defaultTopic;

        log.info("Attempting to dump data to Kafka topic '{}': {}", targetTopic, request.getData());
        try {
            // 2. 执行核心业务逻辑（此处是发送Kafka消息）
            kafkaTemplate.send(targetTopic, request.getData()).get(); // .get() 用于同步发送并获取结果
            log.info("Successfully dumped data to Kafka topic '{}'.", targetTopic);
        } catch (Exception e) {
            // 3. 异常处理与日志记录
            log.error("Failed to dump data to Kafka topic '{}': {}", targetTopic, e.getMessage(), e);
            throw new RuntimeException("Failed to send data to Kafka.", e); // 向上抛出业务异常
        }
    }
}

// src/main/java/com/example/demo/controller/DumpController.java
package com.example.demo.controller;

import com.example.demo.dto.DumpRequest;
import com.example.demo.service.DumpService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid; // 引入校验注解

@RestController
@RequestMapping("/api/v1/dump")
public class DumpController {

    private static final Logger log = LoggerFactory.getLogger(DumpController.class);

    private final DumpService dumpService;

    public DumpController(DumpService dumpService) {
        this.dumpService = dumpService;
    }

    @PostMapping
    public ResponseEntity<String> dumpData(@Valid @RequestBody DumpRequest request) {
        log.info("Received dump request for topic: {}", request.getTopic());
        try {
            dumpService.dumpDataToKafka(request);
            return ResponseEntity.ok("Data successfully dumped to Kafka.");
        } catch (IllegalArgumentException e) {
            log.error("Invalid dump request: {}", e.getMessage());
            return ResponseEntity.badRequest().body(e.getMessage());
        } catch (RuntimeException e) {
            log.error("Error dumping data to Kafka: {}", e.getMessage(), e);
            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body("Failed to dump data: " + e.getMessage());
        }
    }
}