在 .before() 中传递 int 以计算它是否早于 x 天

Question

我想知道如何使用 date.before() 函数检查给定的测量值是否早于 x 天。我试过按照练习中给出的方式将它传递给它，但需要给它一个日期，所以我不知道如何传递它。代码：

class WeatherStation {
    List<Measurements> measurements;
    int days;

    public WeatherStation(int days) {
        this.days = days;
        this.measurements = new ArrayList<>();
    }

    public void addMeasurements(float temperature, float wind, float humidity, float visibility, Date date) {
        measurements.add(new Measurements(temperature, wind, humidity, visibility, date));
        for(Measurements m: measurements) {
            if(m.date.before(days))
        }

    }

Answer 1

您可以从现在减去 "x" 天计算日期，并将其与 before() 方法一起使用。

示例：

Instant now = Instant.now();
Instant now_minus_x_days = now.minus(x, ChronoUnit.DAYS);
someDate.before(Date.from(now_minus_x_days));

在你的 class 中应该是这样的：

class WeatherStation {
    List<Measurements> measurements;
    int days;

    public WeatherStation(int days) {
        this.days = days;
        this.measurements = new ArrayList<>();
    }

    public void addMeasurements(float temperature, float wind, float humidity, float visibility, Date date) {
        measurements.add(new Measurements(temperature, wind, humidity, visibility, date));
        for(Measurements m: measurements) {
            if(m.date.before(Date.from(Instant.now().minus(days, ChronoUnit.DAYS)))) {

            }
        }

    }
}

在 .before() 中传递 int 以计算它是否早于 x 天

Pass int in .before() to calculate if its older than x days

java

java.util.date