LocalDateTime 无法解析“六月”

Question

我帮助设置了一个函数来获取两个字符串并将它们合并到一个日期对象中。 Java - Take two strings and combine into a single date object

在尝试解析 6 月 1 日之前一直运行良好，然后出现以下错误

Exception in thread "AWT-EventQueue-0" java.time.format.DateTimeParseException: Text '1st June' could not be parsed, unparsed text found at index 7
    at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1952)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
    at java.time.LocalDate.parse(LocalDate.java:400)
    at Timetable.ClassManager.parseDate(ClassManager.java:201)
    at Timetable.GoogleAPI.loadClasses(GoogleAPI.java:133)
    at Timetable.ClassManager.loadClasses(ClassManager.java:58)

函数的代码是

public LocalDateTime parseDate(String strDate, String strTime) {
    strTime = strTime + ":00";
    System.out.println("Date: " + strDate);
    System.out.println("Time: " + strTime);
    
    
    LocalDate date = LocalDate.now();
    DateTimeFormatter dtfForDate = new DateTimeFormatterBuilder()
                                    .parseCaseInsensitive()
                                    .parseDefaulting(ChronoField.YEAR, date.getYear())
                                    .appendPattern("d['th']['st']['rd']['nd'] MMM")
                                    .toFormatter(Locale.ENGLISH);

    DateTimeFormatter dtfForTime = DateTimeFormatter.ofPattern("H:m:s", Locale.ENGLISH);
    
    LocalDateTime ldt = LocalDate.parse(strDate, dtfForDate)
                                    .atTime(LocalTime.parse(strTime, dtfForTime));
    System.out.println("Local Date Time: " + ldt);
    
    return ldt;
}

这两张照片给了我

Date: 1st June

Time: 9:15:00

我需要能够同时处理完整的月份名称和月份缩写，即 March 设置为 Mar，April 设置为 Apr。

Answer 1

使用以下模式，这将同时满足三个字母缩写的月份名称以及完整的月份名称：

.appendPattern("d['th']['st']['rd']['nd'] [MMMM][MMM]")

演示：

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.time.temporal.ChronoField;
import java.util.Locale;

public class Main {
    public static void main(String[] args) {
        System.out.println(parseDate("1st June", "9:15:00"));
        System.out.println(parseDate("1st Jun", "9:15:00"));
    }

    public static LocalDateTime parseDate(String strDate, String strTime) {
        LocalDate date = LocalDate.now();
        DateTimeFormatter dtfForDate = new DateTimeFormatterBuilder()
                                        .parseCaseInsensitive()
                                        .parseDefaulting(ChronoField.YEAR, date.getYear())
                                        .appendPattern("d['th']['st']['rd']['nd'] [MMMM][MMM]")
                                        .toFormatter(Locale.ENGLISH);

        DateTimeFormatter dtfForTime = DateTimeFormatter.ofPattern("H:m:s", Locale.ENGLISH);

        LocalDateTime ldt = LocalDate.parse(strDate, dtfForDate).atTime(LocalTime.parse(strTime, dtfForTime));

        return ldt;
    }
}

输出：

2021-06-01T09:15
2021-06-01T09:15

更新

此更新解决了 Meno Hochschild 提出的以下问题：

就我个人而言，我不喜欢这里滥用可选部分。 反例：“1th Jun”或“2st Jun”也会成功 已解析但不应该。

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.time.temporal.ChronoField;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

public class Main {
    public static void main(String[] args) {
        System.out.println(parseDate("1st June", "9:15:00"));
        System.out.println(parseDate("1st Jun", "9:15:00"));
    }

    public static LocalDateTime parseDate(String strDate, String strTime) {
        LocalDate date = LocalDate.now();
        DateTimeFormatter dtfForDate = new DateTimeFormatterBuilder()
                                        .parseCaseInsensitive()
                                        .parseDefaulting(ChronoField.YEAR, date.getYear())
                                        .appendText(ChronoField.DAY_OF_MONTH, ordinalMap())
                                        .appendPattern(" [MMMM][MMM]")
                                        .toFormatter(Locale.ENGLISH);

        DateTimeFormatter dtfForTime = DateTimeFormatter.ofPattern("H:m:s", Locale.ENGLISH);

        LocalDateTime ldt = LocalDate.parse(strDate, dtfForDate).atTime(LocalTime.parse(strTime, dtfForTime));

        return ldt;
    }

    static Map<Long, String> ordinalMap() {
        String[] suffix = { "th", "st", "nd", "rd", "th", "th", "th", "th", "th", "th" };
        Map<Long, String> map = new HashMap<>();
        
        for (int i = 1; i <= 31; i++) 
            map.put((long)i, String.valueOf(i) + suffix[(i > 3 && i < 21) ? 0 : (i % 10)]);
        
        return map;
    }
}

输出：

2021-06-01T09:15
2021-06-01T09:15

礼貌：构建Map 的逻辑基于this excellent answer。