我正在嘗試從外部 API 獲取 JSON 并解析它，以便我可以訪(fǎng)問(wèn) JSON 對(duì)象值，以避免我不需要的值（字段）。我已經(jīng)研究了一點(diǎn) JSONOBject 庫(kù)并解析了對(duì)象，但是，感覺(jué)我做了太多的硬編碼并且根本沒(méi)有正確執(zhí)行，非常感謝反饋。用戶(hù)輸入后輸出結(jié)果：發(fā)送“GET”請(qǐng)求到 URL： https: //api.coindesk.com/v1/bpi/currentprice/（用戶(hù)輸入貨幣）數(shù)據(jù)在 UTC 時(shí)間/日期獲取：2019 年 9 月 17 日 22:51:00 UTC 說(shuō)明：烏克蘭格里夫納匯率浮動(dòng)：253737.6633import org.json.JSONObject;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.net.HttpURLConnection;import java.net.URL;public class App { public static void main(String[] args) throws IOException { BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); System.out.println("Please enter the currency you would like to get BTC current rate for"); String userInput = in.readLine(); try { String url = "https://api.coindesk.com/v1/bpi/currentprice/" + userInput; URL obj = new URL(url); // HttpURLConnection instance is making a request //openConnection() method of URL class opens the connection to specified URL HttpURLConnection con = (HttpURLConnection) obj.openConnection(); // saving the response code from the request int responseCode = con.getResponseCode(); System.out.println("\nSending 'GET' request to URL : " + url); System.out.println("---------------------------------------------"); System.out.println("Response Code from the HTTP request : " + responseCode); System.out.println("---------------------------------------------"); }
1 回答
飲歌長(zhǎng)嘯
TA貢獻(xiàn)1951條經(jīng)驗(yàn) 獲得超3個(gè)贊
ObjectMapper我編寫(xiě)了一個(gè)示例代碼，通過(guò)使用將響應(yīng) json 字符串轉(zhuǎn)換為 POJO 來(lái) 演示我在評(píng)論中所說(shuō)的內(nèi)容。
首先，創(chuàng)建一個(gè)類(lèi)，說(shuō)CoinDeskResponse是存儲(chǔ)轉(zhuǎn)換結(jié)果。
public class CoinDeskResponse {
private TimeInfo time;
private String disclaimer;
private BpiInfo bpi;
//general getters and setters
}
class TimeInfo {
private String updated;
private String updatedISO;
//general getters and setters
}
class BpiInfo {
private String code;
private String symbol;
private String rate;
private String description;
@JsonProperty("rate_float")
private String rateFloat;
//general getters and setters
}
接下來(lái)，創(chuàng)建ObjectMapper響應(yīng)并將其轉(zhuǎn)換為CoinDeskResponsePOJO。然后就可以通過(guò)操作該對(duì)象來(lái)獲取所需的數(shù)據(jù)。
String responseStr = "{\"time\":{\"updated\":\"Sep 18, 2013 17:27:00 UTC\",\"updatedISO\":\"2013-09-18T17:27:00+00:00\"},\"disclaimer\":\"This data was produced from the CoinDesk Bitcoin Price Index. Non-USD currency data converted using hourly conversion rate from openexchangerates.org\",\"bpi\":{\"code\":\"USD\",\"symbol\":\"$\",\"rate\":\"126.5235\",\"description\":\"United States Dollar\",\"rate_float\":126.5235}}";
ObjectMapper mapper = new ObjectMapper();
try {
CoinDeskResponse coinDeskResponse = mapper.readValue(responseStr, CoinDeskResponse.class);
System.out.println(coinDeskResponse.getTime().getUpdated());
System.out.println(coinDeskResponse.getBpi().getDescription());
System.out.println(coinDeskResponse.getBpi().getRateFloat());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
控制臺(tái)輸出：
數(shù)據(jù)在 UTC 時(shí)間/日期獲取：2013 年 9 月 18 日 17:27:00 UTC
描述：美元
浮動(dòng)匯率：126.5235
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