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  • 报错:Unsupported field: HourOfDay

    报错:Unsupported field: HourOfDay

    这个错误就比较搞笑也比较低级了.

    代码如下

    LocalDate now = LocalDate.now();
    String year = now.format(DateTimeFormatter.ofPattern("yyyy"));
    String hour = now.format(DateTimeFormatter.ofPattern("MM-dd-HH"));
    

    报错如下

    Exception in thread "main" java.time.temporal.UnsupportedTemporalTypeException: Unsupported field: HourOfDay
    	at java.time.LocalDate.get0(LocalDate.java:680)
    	at java.time.LocalDate.getLong(LocalDate.java:659)
    	at java.time.format.DateTimePrintContext.getValue(DateTimePrintContext.java:298)
    	at java.time.format.DateTimeFormatterBuilder$NumberPrinterParser.format(DateTimeFormatterBuilder.java:2540)
    	at java.time.format.DateTimeFormatterBuilder$CompositePrinterParser.format(DateTimeFormatterBuilder.java:2179)
    	at java.time.format.DateTimeFormatter.formatTo(DateTimeFormatter.java:1746)
    	at java.time.format.DateTimeFormatter.format(DateTimeFormatter.java:1720)
    	at java.time.LocalDate.format(LocalDate.java:1691)
    	at com.feiyangshop.recommendation.HdfsHandler.main(HdfsHandler.java:21)
    

    我还追踪到了jdk源码中查看.

    private int get0(TemporalField field) {
            switch ((ChronoField) field) {
                case DAY_OF_WEEK: return getDayOfWeek().getValue();
                case ALIGNED_DAY_OF_WEEK_IN_MONTH: return ((day - 1) % 7) + 1;
                case ALIGNED_DAY_OF_WEEK_IN_YEAR: return ((getDayOfYear() - 1) % 7) + 1;
                case DAY_OF_MONTH: return day;
                case DAY_OF_YEAR: return getDayOfYear();
                case EPOCH_DAY: throw new UnsupportedTemporalTypeException("Invalid field 'EpochDay' for get() method, use getLong() instead");
                case ALIGNED_WEEK_OF_MONTH: return ((day - 1) / 7) + 1;
                case ALIGNED_WEEK_OF_YEAR: return ((getDayOfYear() - 1) / 7) + 1;
                case MONTH_OF_YEAR: return month;
                case PROLEPTIC_MONTH: throw new UnsupportedTemporalTypeException("Invalid field 'ProlepticMonth' for get() method, use getLong() instead");
                case YEAR_OF_ERA: return (year >= 1 ? year : 1 - year);
                case YEAR: return year;
                case ERA: return (year >= 1 ? 1 : 0);
            }
            throw new UnsupportedTemporalTypeException("Unsupported field: " + field);
        }
    

    最后把异常抛出的代码在这.

    说明我在now.format(DateTimeFormatter.ofPattern("MM-dd-HH"));HH是不在case之中的.

    为什么case中只有年月日,没有小时和分秒呢?

    emmmmm.

    答案就是:我用错类了

    应该使用LocalDateTime这个类.这个类包含时分秒.

    LocalDateTime now = LocalDateTime.now();
    String year = now.format(DateTimeFormatter.ofPattern("yyyy"));
    String hour = now.format(DateTimeFormatter.ofPattern("MM-dd-HH"));
    

    FIN

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  • 原文地址:https://www.cnblogs.com/krcys/p/9146339.html
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