实现异步天气数据获取与Spring缓存集成

news2024/9/22 13:38:57

你好呀，我是小邹。

在Web应用中，实时天气数据的获取是一个常见的需求，特别是在需要频繁更新天气信息的场景下，如旅游网站、天气应用或任何需要展示地理位置相关天气的应用。然而，频繁的外部API调用不仅会增加服务器的负担，还可能导致网络延迟，影响用户体验。为了优化这一过程，本文将介绍如何在Spring Boot应用中利用异步调用和缓存技术来高效地获取并存储天气数据。

效果图

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引入Spring异步支持

在Spring框架中，可以使用@Async注解来指定方法应该异步执行。这允许应用在等待耗时操作（如网络调用）完成的同时继续处理其他请求，从而提高了整体的响应性和吞吐量。

利用Spring Cache缓存结果

为了减少对远程API的重复调用，我们可以使用Spring Cache框架来缓存天气数据。@Cacheable注解可以自动存储方法的返回值，如果下次请求相同的数据，它将从缓存中读取，而不是重新执行方法。

代码实现

以下代码示例展示了如何在Spring Boot中结合使用@Async和@Cacheable注解来异步获取并缓存天气数据：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import org.springframework.ui.Model;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.data.util.Pair;
import cn.hutool.core.util.StrUtil;
import cn.hutool.core.collection.CollUtil;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.time.LocalDateTime;

@Service
public class WeatherService {

    private static final String WEATHER_CACHE_NAME = "weatherCache";
    private static final String GAO_DE_KEY = "YOUR_GAODE_API_KEY";
    private final RestTemplate restTemplate;

    @Autowired
    public WeatherService(RestTemplate restTemplate) {
        this.restTemplate = restTemplate;
    }

    @Async
    @Cacheable(value = WEATHER_CACHE_NAME, key = "'todayWeather'")
    public void getWeather(Model model) {
        HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
        HashMap<String, String> weatherMap = new HashMap<>();

        // 获取客户端IP地址
        String ip = IpParseUtil.getIpAddr(request);
        List<String> address = IpParseUtil.parse(ip, null);
        String region = "";
        if (address.size() > 3) {
            region = address.get(2) + address.get(3);
        }

        // 地理位置编码
        Map<String, Object> ipInfoMap = restTemplate.getForObject("https://restapi.amap.com/v3/geocode/geo?key=" + GAO_DE_KEY + "&output=json&address=" + region, Map.class);
        List<Object> geocodes = (List<Object>) ipInfoMap.get("geocodes");
        String adCode = (String) ((LinkedHashMap) geocodes.get(0)).get("adcode");

        // 查询天气信息
        Map<String, Object> weatherMapResponse = restTemplate.getForObject("https://restapi.amap.com/v3/weather/weatherInfo?city=" + adCode + "&key=" + GAO_DE_KEY + "&extensions=all", Map.class);
        
        // 处理天气信息
        processWeatherResponse(weatherMapResponse, weatherMap);

        // 将天气数据添加到模型中
        model.addAttribute("weather", weatherMap);
    }

    private void processWeatherResponse(Map<String, Object> weatherMapResponse, HashMap<String, String> weatherMap) {
        if (CollUtil.isEmpty((Collection<?>) weatherMapResponse.get("forecasts"))) {
            // 如果无法获取天气信息，设置默认值
            weatherMap.put("city", "获取定位失败");
            weatherMap.put("weather", "*");
            weatherMap.put("temperature", "*");
            weatherMap.put("reportTime", LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
            weatherMap.put("tomorrowWeather", "*");
            weatherMap.put("tomorrowTemperature", "*");
            weatherMap.put("tomorrowLowTemperature", "*");
        } else {
            // 提取并处理天气信息
            List<Map<String, Object>> forecasts = (List<Map<String, Object>>) weatherMapResponse.get("forecasts");
            String city = forecasts.get(0).get("city").toString().replaceAll("市$", "");
            weatherMap.put("city", city);

            // 实时天气
            Map<String, Object> liveWeather = (Map<String, Object>) forecasts.get(0).get("lives");
            weatherMap.put("weather", (String) liveWeather.get("weather"));
            weatherMap.put("temperature", (String) liveWeather.get("temperature"));
            weatherMap.put("reportTime", (String) liveWeather.get("reporttime"));

            // 天气预报
            List<Map<String, Object>> forecast = (List<Map<String, Object>>) forecasts.get(0).get("casts");
            weatherMap.put("tomorrowWeather", (String) forecast.get(1).get("dayweather"));
            weatherMap.put("tomorrowTemperature", (String) forecast.get(1).get("daytemp"));
            weatherMap.put("tomorrowLowTemperature", (String) forecast.get(1).get("nighttemp"));
        }
    }
}