SpringCloud初练习 天气预报系统（1）

        SpringCloud 是一套分布式的微服务解决方案，里面包含的一些组件统统都是基于springboot构建的 所以说SpringCloud是有很多SpringBoot应用所组成的。springBoot是整个SpringCloud的基石。

天气预报系统：

① 环境搭建 

IntelliJ IDEA 开发工具 ， gradle4+  ， 打击一个springBoot的Web项目

②数据来源

天气预报系统的数据来源：

eg：http://wthrcdn.etouch.cn/weather_mini?city=深圳

        http://wthrcdn.etouch.cn/weather_mini?citykey=101280601

        http://mobile.weather.com.cn/js/citylist.xml

{"data":{"yesterday":{"date":"27日星期二","high":"高温 22℃","fx":"无持续风向","low":"低温 16℃","fl":"<![CDATA[<3级]]>","type":"多云"},"city":"深圳","aqi":"51","forecast":[{"date":"28日星期三","high":"高温 25℃","fengli":"<![CDATA[<3级]]>","low":"低温 19℃","fengxiang":"无持续风向","type":"多云"},{"date":"1日星期四","high":"高温 24℃","fengli":"<![CDATA[<3级]]>","low":"低温 18℃","fengxiang":"无持续风向","type":"多云"},{"date":"2日星期五","high":"高温 24℃","fengli":"<![CDATA[<3级]]>","low":"低温 19℃","fengxiang":"无持续风向","type":"阵雨"},{"date":"3日星期六","high":"高温 25℃","fengli":"<![CDATA[<3级]]>","low":"低温 21℃","fengxiang":"无持续风向","type":"多云"},{"date":"4日星期天","high":"高温 25℃","fengli":"<![CDATA[<3级]]>","low":"低温 21℃","fengxiang":"无持续风向","type":"阵雨"}],"ganmao":"各项气象条件适宜，无明显降温过程，发生感冒机率较低。","wendu":"26"},"status":1000,"desc":"OK"}

③需要的依赖：

搭建一个SpringBoot 的gradle项目  结果如下：

④根据天气预报信息返回的数据创建四个类：  每个类都实现Serlalizable接口，同时提供Set get方法。

Weather类：

 private static final long serialVersionUID = 1L;    private String city;    private String aqi;    private String ganmao;    private String wendu;    private List<Forecast> forecast;    private Yesterday yesterday;

Forecast类

private static final long serialVersionUID = 1L;    private String date;    private String high;    private String fengli;    private String low;    private String fengxiang;    private String type;

Yesterday类

private static final long serialVersionUID = 1L;    private String date;    private String high;    private String low;    private String fx;    private String fl;    private String type;

WeatherResponse类

private static final long serialVersionUID = 1L;    private Weather data;    private Integer status;    private String desc;

⑤创建Service类  先创建一个接口 WeatherDataService 接着写他的实现类

public interface WeatherDataService {    /**     * 根据cityName 获取到该城市的天气情况     * @param cityName     * @return     */    public WeatherResponse getDataByCityName(String cityName);    /**     * 根据cityKey 获取到该城市的天气情况     * @param cityKey     * @return     */    public WeatherResponse getDataByCityKey(String cityKey);}

@Servicepublic class WeatherDataServiceImpl implements WeatherDataService {    private static final String WEATHER_URL = "http://wthrcdn.etouch.cn/weather_mini?";    @Autowired    private RestTemplate restTemplate;    @Override    public WeatherResponse getDataByCityName(String cityName) {        String url = WEATHER_URL + "city=" + cityName;        return getDataByUrl(url);    }    @Override    public WeatherResponse getDataByCityKey(String cityKey) {        String url = WEATHER_URL + "citykey=" + cityKey;        return getDataByUrl(url);    }    /**     * 根据传入的url返回WeatherResponse对象     *     * @param url     * @return     */    private WeatherResponse getDataByUrl(String url) {        //获取到url返回的内容  String类型        ResponseEntity<String> responseEntity = restTemplate.getForEntity(url, String.class);        int statusCode = responseEntity.getStatusCodeValue();        String responseBody = null;        if(statusCode == 200){            responseBody = responseEntity.getBody();        }        //将json数据放到对象中        ObjectMapper mapper = new ObjectMapper();        WeatherResponse ws = null;        try {            ws = mapper.readValue(responseBody,WeatherResponse.class);        } catch (IOException e) {            e.printStackTrace();        }        return ws;    }}

@Configurationpublic class RestConfiguration {    @Bean    public RestTemplate restTemplate(){        StringHttpMessageConverter m = new StringHttpMessageConverter(Charset.forName("UTF-8"));        RestTemplateBuilder restTemplateBuilder = new RestTemplateBuilder();        return restTemplateBuilder.additionalMessageConverters(m).build();    }}

重点内容  实现的内容时在service中发送url请求 然后将返回的结果封装成一个WeatherResponse实例

采用RestTemplate 来发送请求

restTemplate.getForEntity(url, String.class);  发送url之后返回一个ResponseEntity实体，

responseEntity.getStatusCodeValue();可获取到状态码  当为200时表明成功。  最后将String类型的json数据转为对象

使用的时jackson的转换

ObjectMapper mapper = new ObjectMapper();

ws = mapper.readValue(responseBody,WeatherResponse.class);

可能会出现返回的结果为乱码的现象：

处理方法：

StringHttpMessageConverter m = new StringHttpMessageConverter(Charset.forName("UTF-8"));        RestTemplateBuilder restTemplateBuilder = new RestTemplateBuilder();        return restTemplateBuilder.additionalMessageConverters(m).build();

 RestTempalate 字符串类型默认StringHttpMessageConverter做转码，而StringHttpMessageConverter的默认编码集是ISO8859-1,

⑥ 创建Controller类  浏览器访问测试

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

浏览器访问：http://localhost:8080/weather/cityName/北京