关于java:基于JAVA的免费天气预报接口查询

1、开明接口

天气预报接口服务应用的聚合数据提供的收费接口，每天能够 100 次收费调用。能够通过 https://www.juhe.cn/docs/api/id/73 注册及开明。

2、通过 Java 发动城市天气查问

package cn.juhe;
import net.sf.json.JSONObject;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.Map;
public class SimpleWeather {
// 天气情况查问接口地址
public static String API_URL = "http://apis.juhe.cn/simpleWeather/query";
// 接口申请 Key
public static String API_KEY = "xxxxxxxxxxxxxx";

public static void main(String[] args) {
    String cityName = "北京";
    queryWeather(cityName);
}

/**
 * 依据城市名查问天气情况
 *
 * @param cityName
 */
public static void queryWeather(String cityName) {Map<String, Object> params = new HashMap<>();// 组合参数
    params.put("city", cityName);
    params.put("key", API_KEY);
    String queryParams = urlencode(params);

    String response = doGet(API_URL, queryParams);
    try {JSONObject jsonObject = JSONObject.fromObject(response);
        int error_code = jsonObject.getInt("error_code");
        if (error_code == 0) {System.out.println("调用接口胜利");

            JSONObject result = jsonObject.getJSONObject("result");
            JSONObject realtime = result.getJSONObject("realtime");

            System.out.printf("城市：%s%n", result.getString("city"));
            System.out.printf("天气：%s%n", realtime.getString("info"));
            System.out.printf("温度：%s%n", realtime.getString("temperature"));
            System.out.printf("湿度：%s%n", realtime.getString("humidity"));
            System.out.printf("风向：%s%n", realtime.getString("direct"));
            System.out.printf("风力：%s%n", realtime.getString("power"));
            System.out.printf("空气质量：%s%n", realtime.getString("aqi"));
        } else {System.out.println("调用接口失败：" + jsonObject.getString("reason"));
        }
    } catch (Exception e) {e.printStackTrace();
    }
}

/**
 * get 形式的 http 申请
 *
 * @param httpUrl 申请地址
 * @return 返回后果
 */
public static String doGet(String httpUrl, String queryParams) {
    HttpURLConnection connection = null;
    InputStream inputStream = null;
    BufferedReader bufferedReader = null;
    String result = null;// 返回后果字符串
    try {
        // 创立近程 url 连贯对象
        URL url = new URL(new StringBuffer(httpUrl).append("?").append(queryParams).toString());
        // 通过近程 url 连贯对象关上一个连贯，强转成 httpURLConnection 类
        connection = (HttpURLConnection) url.openConnection();
        // 设置连贯形式：get
        connection.setRequestMethod("GET");
        // 设置连贯主机服务器的超时工夫：15000 毫秒
        connection.setConnectTimeout(5000);
        // 设置读取近程返回的数据工夫：60000 毫秒
        connection.setReadTimeout(6000);
        // 发送申请
        connection.connect();
        // 通过 connection 连贯，获取输出流
        if (connection.getResponseCode() == 200) {inputStream = connection.getInputStream();
            // 封装输出流，并指定字符集
            bufferedReader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
            // 存放数据
            StringBuilder sbf = new StringBuilder();
            String temp;
            while ((temp = bufferedReader.readLine()) != null) {sbf.append(temp);
                sbf.append(System.getProperty("line.separator"));
            }
            result = sbf.toString();}
    } catch (IOException e) {e.printStackTrace();
    } finally {
        // 敞开资源
        if (null != bufferedReader) {
            try {bufferedReader.close();
            } catch (IOException e) {e.printStackTrace();
            }
        }
        if (null != inputStream) {
            try {inputStream.close();
            } catch (IOException e) {e.printStackTrace();
            }
        }
        if (connection != null) {connection.disconnect();// 敞开近程连贯
        }
    }
    return result;
}

/**
 * 将 map 型转为申请参数型
 *
 * @param data
 * @return
 */
public static String urlencode(Map<String, ?> data) {StringBuilder sb = new StringBuilder();
    for (Map.Entry<String, ?> i : data.entrySet()) {
        try {sb.append(i.getKey()).append("=").append(URLEncoder.encode(i.getValue() + "","UTF-8")).append("&");
        } catch (UnsupportedEncodingException e) {e.printStackTrace();
        }
    }
    String result = sb.toString();
    result = result.substring(0, result.lastIndexOf("&"));
    return result;
}
}