如何获得 Java 中给定日期的 previous/last 星期六？

Question

例如：- 字符串 fromDate="09/18/2020"; 我希望我的实际开始日期是上周六，即“09/12/2020”。

另一个例子：- 字符串 fromDate="09/01/2020"; 我希望我的实际开始日期是上周六，即“08/29/2020”。

Answer 1

TemporalAdjusters.previous

import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.time.temporal.TemporalAdjusters;
import java.util.Locale;

public class Main {
    public static void main(String[] args) {
        String fromDate = "09/18/2020";
        DateTimeFormatter dtf = DateTimeFormatter.ofPattern("M/d/u", Locale.ENGLISH);

        LocalDate date = LocalDate.parse(fromDate, dtf);

        LocalDate result = date.with(TemporalAdjusters.previous(DayOfWeek.SATURDAY));

        // Default LocalDate#toString implementation
        System.out.println(result);

        // Formatted
        System.out.println(result.format(dtf));
    }
}

输出：

2020-09-12
9/12/2020

从 Trail: Date Time.

了解有关现代日期时间的更多信息 API

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