005 日期时间与字符串转换

1. 字符串转LocalDate

public static LocalDate parseDateString(String dateString, String pattern){
    try{
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
        return LocalDate.parse(dateString, formatter);
    }catch (DateTimeParseException ex){
        ex.printStackTrace();
        return null;
    }
}

2. LocalDate转字符串

public static String formatDate(LocalDate date, String pattern){
    DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern(pattern);
    return date.format(dateFormatter);
}

3. 字符串转LocalDateTime

public static LocalDateTime parseTimeString(String timeString, String pattern){
    try{
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
        return LocalDateTime.parse(timeString, formatter);
    }catch (DateTimeParseException ex){
        ex.printStackTrace();
        return null;
    }
}

4. LocalDateTime转字符串

public static String formatTime(LocalDateTime time, String pattern){
    DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern(pattern);
    return time.format(dateFormatter);
}

测试代码：

public static void main(String[] args) {
    LocalDate date = parseDateString("2022年12月8日", "y年M月d日");
    System.out.println(formatDate(date, "MM/dd/yyyy"));

    LocalDateTime time = parseTimeString("2022年12月8日 8:22:5","y年M月d日 H:m:s");
    System.out.println(formatTime(time, "yyyy-MM-dd HH时mm分ss秒"));
}

输出结果是：

12/08/2022
2022-12-08 08时22分05秒