有没有办法在 JSONArray 中对双打进行四舍五入？

Is there a way to round doubles in JSONArray?

提问人：Davido 提问时间：11/11/2023 最后编辑：Davido 更新时间：11/12/2023 访问量：109

问：

我有一个JSON文本格式。因此，我首先将其放入对象中，然后放入 Map，该映射的值中有另一个映射（JSON 的文本格式具有内部和外部映射类型）。在内部映射中，打印带有两位小数的 JSONDouble 不是问题（我可以使用，但是当 JSONArray 出现时，我不能这样做。printf("%.2f"))

我试过功能，但它不起作用。printf

如果可能，请不要使用流。

代码如下：

package doplomski.rad.glavna;

import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;
import java.math.BigDecimal;
import java.net.URI;
import java.util.*;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.net.http.HttpClient;
import java.io.IOException;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

public class Glavna {
    public static void main(String[] args) throws ParseException {

        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("API url"))
                .header("X-RapidAPI-Host", "website url")
                .header("X-RapidAPI-Key", "key")
                .method("GET", HttpRequest.BodyPublishers.noBody())
                .build();

        HttpResponse<String> response = null;

        try {
            response = HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString());
        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println(response.body());
        System.out.println();

        Object obj = new JSONParser().parse(response.body());

        Map<String, Map<String, BigDecimal>> output = (Map) obj;

        System.out.printf("%.2f%n", output.get("outputs").get("ac_annual"));
        System.out.printf("%.2f%n", output.get("outputs").get("solrad_annual"));
        System.out.printf("%.2f%n", output.get("outputs").get("capacity_factor"));
        System.out.println(output.get("outputs").get("ac_monthly"));
        System.out.println(output.get("outputs").get("dc_monthly"));
        System.out.println(output.get("outputs").get("poa_monthly"));
        System.out.println(output.get("outputs").get("solrad_monthly"));

    }

并输出：

{"inputs":{"azimuth":"180","system_capacity":"4","losses":"14","array_type":"1","module_type":"0","gcr":"0.4","dc_ac_ratio":"1.2","inv_eff":"96.0","radius":"0","dataset":"nsrdb","tilt":"10","address":"boulder, co","soiling":[12.0,4.0,45.0,23.0,9.0,99.0,67.0,12.54,54.0,9.0,0.0,7.6],"albedo":"0.3","bifaciality":"0.7"},"errors":[],"warnings":[],"version":"8.2.1","ssc_info":{"version":280,"build":"Linux 64 bit GNU/C++ Oct 18 2023 07:13:03","module":"pvwattsv8"},"station_info":{"lat":40.0099983215332,"lon":-105.2600021362305,"elev":1635.640014648438,"tz":-7.0,"location":"149190","city":"","state":"Colorado","country":"United States","solar_resource_file":"149190.csv","distance":1750,"weather_data_source":"NSRDB PSM V3 GOES tmy-2020 3.2.0"},"outputs":{"ac_monthly":[350.4450331552693,436.3879540968705,340.7495159069064,442.1920779147474,534.4142671193669,19.89441005557222,206.6577352851099,492.4427511771748,241.7735300594523,382.6085934358003,376.0863140563925,306.6293313390505],"poa_monthly":[104.9805590746965,131.3527386112043,104.2011355720695,138.6804496432297,177.348356252559,9.001239090243104,70.67352420990476,166.9411671806375,79.89308311196012,122.4161912004151,115.6650356864296,91.94797329425062],"solrad_monthly":[3.386469647570856,4.69116923611444,3.361326953937725,4.622681654774324,5.720914717824484,0.3000413030081034,2.279791103545315,5.385198941310887,2.663102770398671,3.948909393561777,3.855501189547655,2.966063654653246],"dc_monthly":[368.0682926594546,457.2045927636358,359.1841462238203,464.7078109487218,561.0990701509306,27.17952816676697,221.2817047541209,517.4117655437504,256.4903025712858,402.0961281476057,394.804951938705,322.3432439889111],"ac_annual":4130.281513601723,"solrad_annual":3.598430880520624,"capacity_factor":11.78733308676288}}

4130,28
3,60
11,79
[350.4450331552693,436.3879540968705,340.7495159069064,442.1920779147474,534.4142671193669,19.89441005557222,206.6577352851099,492.4427511771748,241.7735300594523,382.6085934358003,376.0863140563925,306.6293313390505]
[368.0682926594546,457.2045927636358,359.1841462238203,464.7078109487218,561.0990701509306,27.17952816676697,221.2817047541209,517.4117655437504,256.4903025712858,402.0961281476057,394.804951938705,322.3432439889111]
[104.9805590746965,131.3527386112043,104.2011355720695,138.6804496432297,177.348356252559,9.001239090243104,70.67352420990476,166.9411671806375,79.89308311196012,122.4161912004151,115.6650356864296,91.94797329425062]
[3.386469647570856,4.69116923611444,3.361326953937725,4.622681654774324,5.720914717824484,0.3000413030081034,2.279791103545315,5.385198941310887,2.663102770398671,3.948909393561777,3.855501189547655,2.966063654653246]
Java 数组 JSON 字典 舍入

评论

3赞 Sören 11/11/2023
请不要上传代码/数据/错误的图像。
0赞 aled 11/11/2023
编辑您的问题以共享输入、实际输出和预期输出。
0赞 Reilas 11/11/2023
遍历数组。
0赞 Davido 11/12/2023
这是编辑后的代码。

答：

0赞 Oleg Cherednik 11/12/2023 #1

所以你做对了。您只需要从 中获取所有值，分别转换它们并构建一个 .JSONArrayString

public static String toString(JSONArray jsonArray) {
    return IntStream.rangeClosed(0, jsonArray.length())
            .mapToObj(i -> String.format("%.2f", (BigDecimal) jsonArray.get(i)))
            .collect(Collectors.joining(",", "[", "]"));
}

最后，您的代码片段可能如下所示：

System.out.printf("%.2f%n", output.get("outputs").get("ac_annual"));
System.out.printf("%.2f%n", output.get("outputs").get("solrad_annual"));
System.out.printf("%.2f%n", output.get("outputs").get("capacity_factor"));
System.out.println(toString(output.get("outputs").get("ac_monthly")));
System.out.println(toString(output.get("outputs").get("dc_monthly")));
System.out.println(toString(output.get("outputs").get("poa_monthly")));
System.out.println(toString(output.get("outputs").get("solrad_monthly")));

评论

0赞 Davido 11/12/2023
它说：无法解析“JSONArray”中的方法“length”
0赞 Oleg Cherednik 11/12/2023
你用什么？你能告诉我全名吗？JSONArray
0赞 Davido 11/12/2023
另外，当我添加 toString（） 方法时，它说所需的类型是 JSONArray，而不是 Float
0赞 Oleg Cherednik 11/12/2023
当然，我可以在调试中看到 - 这是BigDecimal
0赞 Davido 11/12/2023
现在在这里添加了整个代码。不知道我在哪里可以看到类型od JSONarray
0赞 Davido 11/12/2023 #2

谢谢你们抽出时间接受采访。 这是我问题的解决方案：

HttpResponse<String> response = null;

        try {
            response = HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString());
        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println(response.body());
        System.out.println();

        Object obj = new JSONParser().parse(response.body());

        Map<String, Map<String, Object>> output = (Map) obj;

        System.out.printf("%.2f%n", ((Double) output.get("outputs").get("ac_annual")));
        System.out.printf("%.2f%n", ((Double) output.get("outputs").get("solrad_annual")));
        System.out.printf("%.2f%n", ((Double) output.get("outputs").get("capacity_factor")));

        JSONArray acMonthlyArray = (JSONArray) output.get("outputs").get("ac_monthly");
        System.out.println(toString(acMonthlyArray));
        JSONArray dcMonthlyArray = (JSONArray) output.get("outputs").get("dc_monthly");
        System.out.println(toString(dcMonthlyArray));
        JSONArray poaMonthly = (JSONArray) output.get("outputs").get("poa_monthly");
        System.out.println(toString(poaMonthly));
        JSONArray solrad_monthly = (JSONArray) output.get("outputs").get("solrad_monthly");
        System.out.println(toString(solrad_monthly));
    }

    public static String toString(JSONArray array) {
        StringBuilder result = new StringBuilder("[");

        for (int i = 0; i < array.size(); i++) {
            BigDecimal value = new BigDecimal(array.get(i).toString());
            result.append(String.format("%.2f", value));

            if (i < array.size() - 1) {
                result.append(", ");
            }
        }

        result.append("]");
        return result.toString();
    }
}

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