基于Spring Boot的天气预报服务-白红宇

本文，我们将基于 Spring Boot 技术来实现一个微服务天气预报服务接口——micro-weather-basic。micro-weather-basic 的作用是实现简单的天气预报功能，可以根据不同的城市，查询该城市的实时天气情况。

开发环境

Gradle 4.0

Spring Boot 1.5.6

Apache HttpClient 1.5.3

数据来源

理论上，天气的数据是天气预报的实现基础。本应用与实际的天气数据无关，理论上，可以兼容多种数据来源。但为求简单，我们在网上找了一个免费、可用的天气数据接口。

天气数据来源为中华万年历。例如：
- 通过城市名字获得天气数据：
- 通过城市id获得天气数据：

城市ID列表。每个城市都有一个唯一的ID作为标识。见

调用天气服务接口示例，我们以“深圳”城市为例，可用看到如下天气数据返回。

{    "data": {        "yesterday": {            "date": "1日星期五",            "high": "高温 33℃",            "fx": "无持续风向",            "low": "低温 26℃",            "fl": "",            "type": "多云"        },        "city": "深圳",        "aqi": "72",        "forecast": [            {                "date": "2日星期六",                "high": "高温 32℃",                "fengli": "",                "low": "低温 26℃",                "fengxiang": "无持续风向",                "type": "阵雨"            },            {                "date": "3日星期天",                "high": "高温 29℃",                "fengli": "",                "low": "低温 26℃",                "fengxiang": "无持续风向",                "type": "大雨"            },            {                "date": "4日星期一",                "high": "高温 29℃",                "fengli": "",                "low": "低温 26℃",                "fengxiang": "西南风",                "type": "暴雨"            },            {                "date": "5日星期二",                "high": "高温 31℃",                "fengli": "",                "low": "低温 27℃",                "fengxiang": "无持续风向",                "type": "阵雨"            },            {                "date": "6日星期三",                "high": "高温 32℃",                "fengli": "",                "low": "低温 27℃",                "fengxiang": "无持续风向",                "type": "阵雨"            }        ],        "ganmao": "风较大，阴冷潮湿，较易发生感冒，体质较弱的朋友请注意适当防护。",        "wendu": "29"    },    "status": 1000,    "desc": "OK"}

我们通过观察数据，来了解每个返回字段的含义。

"city": 城市名称

"aqi": 空气指数,

"wendu": 实时温度

"date": 日期，包含未来5天

"high":最高温度

"low": 最低温度

"fengli": 风力

"fengxiang": 风向

"type": 天气类型

以上数据，是我们需要的天气数据的核心数据，但是，同时也要关注下面两个字段：

"status": 接口调用的返回状态，返回值“1000”,意味着数据是接口正常

"desc": 接口状态的描述，“OK”代表接口正常

重点关注返回值不是“1000”的情况,说明，这个接口调用异常了。

初始化一个 Spring Boot 项目

初始化一个 Spring Boot 项目 micro-weather-basic，该项目可以直接在我们之前章节课程中的 basic-gradle 项目基础进行修改。同时，为了优化项目的构建速度，我们对Maven中央仓库地址和 Gradle Wrapper 地址做了调整。其中细节暂且不表，读者可以自行参阅源码，或者学习笔者所著的《Spring Boot 教程》（）。其原理，我也整理到我的博客中了：

项目配置

添加 Apache HttpClient 的依赖，来作为我们Web请求的客户端。

// 依赖关系dependencies {    //...     // 添加  Apache HttpClient 依赖    compile('org.apache.httpcomponents:httpclient:4.5.3')     //...}

创建天气信息相关的值对象

创建com.waylau.spring.cloud.vo包，用于相关值对象。创建天气信息类 Weather

public class Weather implements Serializable {         private static final long serialVersionUID = 1L;            private String city;    private String aqi;    private String wendu;    private String ganmao;    private Yesterday yesterday;    private List
    
      forecast;     public String getCity() {        return city;    }    public void setCity(String city) {        this.city = city;    }    public String getAqi() {        return aqi;    }    public void setAqi(String aqi) {        this.aqi = aqi;    }    public String getWendu() {        return wendu;    }    public void setWendu(String wendu) {        this.wendu = wendu;    }    public String getGanmao() {        return ganmao;    }    public void setGanmao(String ganmao) {        this.ganmao = ganmao;    }    public Yesterday getYesterday() {        return yesterday;    }    public void setYesterday(Yesterday yesterday) {        this.yesterday = yesterday;    }    public List
     
       getForecast() {        return forecast;    }    public void setForecast(List
      
        forecast) {        this.forecast = forecast;    }}

昨日天气信息：

public class Yesterday implements Serializable {     private static final long serialVersionUID = 1L;        private String date;    private String high;    private String fx;    private String low;    private String fl;    private String type;    public Yesterday() {    }        public String getDate() {        return date;    }    public void setDate(String date) {        this.date = date;    }    public String getHigh() {        return high;    }    public void setHigh(String high) {        this.high = high;    }    public String getFx() {        return fx;    }    public void setFx(String fx) {        this.fx = fx;    }    public String getLow() {        return low;    }    public void setLow(String low) {        this.low = low;    }    public String getFl() {        return fl;    }    public void setFl(String fl) {        this.fl = fl;    }    public String getType() {        return type;    }    public void setType(String type) {        this.type = type;    }}

未来天气信息：

public class Forecast implements Serializable {        private static final long serialVersionUID = 1L;        private String date;    private String high;    private String fengxiang;    private String low;    private String fengli;    private String type;    public String getDate() {        return date;    }    public void setDate(String date) {        this.date = date;    }    public String getHigh() {        return high;    }    public void setHigh(String high) {        this.high = high;    }    public String getFengxiang() {        return fengxiang;    }    public void setFengxiang(String fengxiang) {        this.fengxiang = fengxiang;    }    public String getLow() {        return low;    }    public void setLow(String low) {        this.low = low;    }    public String getFengli() {        return fengli;    }    public void setFengli(String fengli) {        this.fengli = fengli;    }    public String getType() {        return type;    }    public void setType(String type) {        this.type = type;    }    public Forecast() {    } }

WeatherResponse 作为整个消息的返回对象

public class WeatherResponse implements Serializable {    private static final long serialVersionUID = 1L;    private Weather data; // 消息数据    private String status; // 消息状态    private String desc; // 消息描述    public Weather getData() {        return data;    }    public void setData(Weather data) {        this.data = data;    }    public String getStatus() {        return status;    }    public void setStatus(String status) {        this.status = status;    }    public String getDesc() {        return desc;    }    public void setDesc(String desc) {        this.desc = desc;    }}

服务接口及实现

定义了获取服务的两个接口方法

public interface WeatherDataService {    /**     * 根据城市ID查询天气数据     * @param cityId     * @return     */    WeatherResponse getDataByCityId(String cityId);        /**     * 根据城市名称查询天气数据     * @param cityId     * @return     */    WeatherResponse getDataByCityName(String cityName);}

其实现为:

@Servicepublic class WeatherDataServiceImpl implements WeatherDataService {    @Autowired    private RestTemplate restTemplate;    private final String WEATHER_API = "http://wthrcdn.etouch.cn/weather_mini";    @Override    public WeatherResponse getDataByCityId(String cityId) {        String uri = WEATHER_API + "?citykey=" + cityId;        return this.doGetWeatherData(uri);    }    @Override    public WeatherResponse getDataByCityName(String cityName) {        String uri = WEATHER_API + "?city=" + cityName;        return this.doGetWeatherData(uri);    }    private WeatherResponse doGetWeatherData(String uri) {        ResponseEntity
    
      response = restTemplate.getForEntity(uri, String.class);        String strBody = null;        if (response.getStatusCodeValue() == 200) {            strBody = response.getBody();        }        ObjectMapper mapper = new ObjectMapper();        WeatherResponse weather = null;        try {            weather = mapper.readValue(strBody, WeatherResponse.class);        } catch (IOException e) {            e.printStackTrace();        }        return weather;    }}

返回的天气信息采用了 Jackson 来进行反序列化成为 WeatherResponse 对象。

控制器层

控制器层暴露了RESTful API 地址。

@RestController@RequestMapping("/weather")    public class WeatherController {    @Autowired    private WeatherDataService weatherDataService;        @GetMapping("/cityId/{cityId}")    public WeatherResponse getReportByCityId(@PathVariable("cityId") String cityId) {        return weatherDataService.getDataByCityId(cityId);    }        @GetMapping("/cityName/{cityName}")    public WeatherResponse getReportByCityName(@PathVariable("cityName") String cityName) {        return weatherDataService.getDataByCityName(cityName);    }}

@RestController自动会将返回的数据，序列化成 JSON数据格式。

配置类

RestConfiguration 是 RestTemplate 的配置类。

@Configurationpublic class RestConfiguration {    @Autowired      private RestTemplateBuilder builder;      @Bean      public RestTemplate restTemplate() {          return builder.build();      }}

访问API

运行项目之后，访问项目的 API ：

能看到如下的数据返回

weather-data

源码

本章节的源码，见 samples目录下的micro-weather-basic。