这是您的API实现的问题;终结点更改了域字段名称和/或域名。这将导致重新导入所述数据时出现问题。
该或前端与端点的API文档不匹配。
字段名/域名应与域/资源匹配，除非您要进行某种程度的混淆，然后接受您需要一个中间层来充当翻译（即EDI）。
您希望仅通过更改请求方法，就可以将输出作为输入由同一个端点读取。
我的建议（最简单的解决方案）：更改原始端点以匹配域/资源字段名称

如果你有机会使用Jackson库，你可以这样做：

ForecastGhi request = objectMapper.readValue(jsonAsText, ForecastGhi.class);

创建objectMapper并配置为在属性未知时失败（以防万一）

private String getJsonAsTextFromRest() {
        String message = " {\"forecasts\":[{\"period_end\":\"2021-01-15T01:00:00.0000000Z\",\"period\":\"PT30M\",\"ghi90\":0,\"ghi\":0,\"ghi10\":0},{\"period_end\":\"2021-01-15T01:30:00.0000000Z\",\"period\":\"PT31M\",\"ghi90\":0,\"ghi\":0,\"ghi10\":0},{\"period_end\":\"2021-01-15T02:00:00.0000000Z\",\"period\":\"PT32M\",\"ghi90\":0,\"ghi\":0,\"ghi10\":0}]}";
        return message;
    }

 @Override
    public void run(String... arg0) throws Exception {
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, true);
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        String jsonAsText = getJsonAsTextFromRest();
        ForecastGhi request = objectMapper.readValue(jsonAsText, ForecastGhi.class);
        request.getForecast().stream().forEach(it -> System.out.println(it.getPeriod() + " " + it.getGhi()));

    }

public class IrradianciaGlobalHorizontal {
    private Date period_end;
    private String period;
    private int ghi90;
    private int ghi;
    private int ghi10;

    public int getGhi() {
        return this.ghi;
    }

    public void setGhi(int ghi) {
        this.ghi = ghi;
    }

    public  int getGhi90() {
        return this.ghi90;
    }

    public void setGhi90(int ghi90) {
        this.ghi90 = ghi90;
    }

    public int getGhi10() {
        return this.ghi10;
    }

    void setGhi10(int ghi10) {
        this.ghi10 = ghi10;
    }

    public Date getPeriod_end() {
        return this.period_end;
    }

    public void setPeriod_end(Date period_end) {
        this.period_end = period_end;
    }

    public String getPeriod() {
        return this.period;
    }

    public void setPeriod(String period) {
        this.period = period;
    }
}

预测Ghi类。

import com.fasterxml.jackson.annotation.JsonProperty;

public class ForecastGhi {

    private ArrayList<IrradianciaGlobalHorizontal> forecast;

    @JsonProperty("forecasts")//It must be the same as the json property
    public ArrayList<IrradianciaGlobalHorizontal> getForecast() {
        return forecast;
    }

    @JsonProperty("forecasts")
    public void setForecast(ArrayList<IrradianciaGlobalHorizontal> forecast) {
        this.forecast = forecast;
    }

}

结果：

• PT 30 M 0型
• PT 31 M 0型发动机
• PT 32 M 0型
  相依性等级：

compile group: 'com.fasterxml.jackson.core', name: 'jackson-core', version: '2.12.1'

或者

相依性Maven：

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.12.1</version>
</dependency>

注意：在您的json示例中，您使用了forecasts，但您的java属性名称是forecasts。在这种情况下，必须使用@JsonProperty（“forecasts”）来修饰属性。如果您不这样做，则会出现如下错误：com.fasterxml.Jackson.databind.exc.UnrecognizedPropertyException：无法识别的字段“预测”