java - 字符串中的月年至今 Java 8

Question

DateTimeFormatter dateFormat = DateTimeFormatter.ofPattern("MM/yyyy");
LocalDate parsedDate = LocalDate.parse(entryOne.getKey(), dateFormat)

获取异常

Text '03/2018' could not be parsed: Unable to obtain LocalDate from TemporalAccessor:

如何使用具有默认月份第一天的 Java 8 解析此字符串并转换为日期。我们使用的东西。

TemporalAdjusters.firstDayOfMonth()

Answer 1

将 MM/yyyy 字符串转换为 LocalDate 时，您有两种选择:

• 解析为 YearMonth，然后转换为 LocalDate:

  String date = "04/2018";
  DateTimeFormatter dateFormat = DateTimeFormatter.ofPattern("MM/yyyy");
  YearMonth yearMonth = YearMonth.parse(date, dateFormat);
  LocalDate parsedDate = yearMonth.atDay(1);
  System.out.println(parsedDate); // prints: 2018-04-01
  

• 使用定义了默认月份日期的 DateTimeFormatter:

  String date = "04/2018";
  DateTimeFormatter dateFormat = new DateTimeFormatterBuilder()
          .appendPattern("MM/yyyy")
          .parseDefaulting(ChronoField.DAY_OF_MONTH, 1)
          .toFormatter();
  LocalDate parsedDate = LocalDate.parse(date, dateFormat);
  System.out.println(parsedDate); // prints: 2018-04-01