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Java:处理日期

java-date date list java

1

Phillip · 技术社区 · 6 年前

我对Java很陌生。所以请容忍我。我有4个变量:

mode =  prior|later|value;(can have either of these 3 values)
occurrence = 2
day = Wednesday
eta = 14:00

我正在尝试实现一个方法,它将返回一个列表 date 基于以下标准:

案例1: (mode=prior,occurence=2,day=wednesday,eta=14:00)

应返回下个月的前两个星期三的日期。

产出=【2018年8月1日星期三14:00:00,2018年8月8日星期三14:00:00】

案例2: mode=later,occurence=2,day=wednesday,eta=14:00 )

应返回下个月最后两个星期三的日期(从当月算起)。

产出=【2018年8月22日星期三14:00:00,2018年8月29日星期三14:00:00】

案例3: (mode=value,occurence=3,day=wednesday,eta=14:00)

应返回下个月的第3个星期三的日期。

output = [Wed Aug 15 14:00:00 2018, Wed Aug 29 14:00:00 2018]

这就是我迄今为止所做的,

public static List<Date> getDates(Calendar c, String mode, int occurrence, int dayNo, String eta) {
            List<Date> dates = new ArrayList<Date>();
            switch(mode) {
            case "value": {
                String[] times = eta.split(":");
                c.set(Calendar.DAY_OF_WEEK, dayNo);  
                c.set(Calendar.DAY_OF_WEEK_IN_MONTH, occurrence);
                c.set(Calendar.MONTH, Calendar.JULY + 1); 
                c.set(Calendar.YEAR, 2018);
                c.set(Calendar.HOUR_OF_DAY, Integer.parseInt(times[0]));
                c.set(Calendar.MINUTE, Integer.parseInt(times[1]));
                dates.add(c.getTime());
            }
            }
            return dates;
        }

有没有更好的方法来做我所做的。还有谁能帮我实施案例1和案例2吗?

2 回复 | 直到 6 年前

1

2

Basil Bourque 6 年前

Calendar GregorianCalendar ZonedDateTime

type-safety typos

enum Oracle Tutorial

public enum Mode {
    PRIOR ,
    LATER ,
    VALUE
}

DayOfWeek DayOfWeek.WEDNESDAY

LocalTime

LocalTime lt = LocalTime.of( 14 , 0 ) ;

YearMonth

ZoneId z = ZoneId.of( "Africa/Tunis" ) ; // Or "America/Chicago", etc.
YearMonth ym = YearMonth.now( z ) ;

LocalDate

YearMonth ym = YearMonth.from( myLocalDate ) ;

OOP

proper time zone name continent/region America/Montreal Africa/Casablanca Pacific/Auckland EST IST

public static List< ZonedDateTime > getDates( 
    YearMonth ym , 
    Mode mode , 
    int occurrences , 
    DayOfWeek dow , 
    LocalTime lt ,
    ZoneId z
) { â¦

Mode.PRIOR Mode.LATER TemporalAdjuster TemporalAdjusters

occurrences

switch Mode discussed here PRIOR case PRIOR: case Mode.PRIOR:

List moments

int initialCapacity = 5; // Max five weeks in any month.
List< ZonedDateTime > moments = new ArrayList<>( initialCapacity );

    LocalDate firstDowOfMonth = ym.atDay( 1 ).with( TemporalAdjusters.firstInMonth( dow ) );

    for ( int i = 0 ; i < occurrences ; i++ ) {
        LocalDate ld = firstDowOfMonth.plusWeeks( i );
        ZonedDateTime zdt = ZonedDateTime.of( ld , lt , z );
        if ( YearMonth.from( zdt ).equals( ym ) ) {  // If in same monthâ¦
            moments.add( zdt );
        }
    }

        // Start with last day-of-week in month.
        LocalDate lastDowOfMonth = ym.atDay( 1 ).with( TemporalAdjusters.lastInMonth( dow ) );
        // Work our way up through the month, subtracting a week at a time.
        for ( int i = 0 ; i < occurrences ; i++ ) {
            LocalDate ld = lastDowOfMonth.minusWeeks( i );
            ZonedDateTime zdt = ZonedDateTime.of( ld , lt , z );
            if ( YearMonth.from( zdt ).equals( ym ) ) {  // If in same monthâ¦
                moments.add( zdt );
            }
        }

        Collections.sort( moments ); // If you want the list to be in chronological order, sort.  Otherwise in reverse chronological order for this `Mode.LATER`.

`Mode.VALUE`

        LocalDate nthDowInMonth = ym.atDay( 1 ).with( TemporalAdjusters.dayOfWeekInMonth( occurrences , dow ) );

        ZonedDateTime zdt = ZonedDateTime.of( nthDowInMonth , lt , z );

        if ( YearMonth.from( zdt ).equals( ym ) ) {  // If in same monthâ¦
            moments.add( zdt );
        }

// Simulate arguments passed.
LocalTime lt = LocalTime.of( 14 , 0 );
ZoneId z = ZoneId.of( "Africa/Tunis" ); // Or "America/Chicago", etc.
YearMonth ym = YearMonth.now( z );
DayOfWeek dow = DayOfWeek.WEDNESDAY;
Mode mode = Mode.PRIOR ;  // Mode.PRIOR, Mode.LATER, Mode.VALUE.
int occurrences = 3; // TODO: Add code to verify this value is in range of 1-5, not zero, not >5.

// Logic
int initialCapacity = 5; // Max five weeks in any month.
List< ZonedDateTime > moments = new ArrayList<>( initialCapacity );
switch ( mode ) {
    case PRIOR:
        // Start with first day-of-week in month.
        LocalDate firstDowOfMonth = ym.atDay( 1 ).with( TemporalAdjusters.firstInMonth( dow ) );
        // Work our way down through the month, adding a week at a time.
        for ( int i = 0 ; i < occurrences ; i++ ) {
            LocalDate ld = firstDowOfMonth.plusWeeks( i );
            ZonedDateTime zdt = ZonedDateTime.of( ld , lt , z );
            if ( YearMonth.from( zdt ).equals( ym ) ) {  // If in same monthâ¦
                moments.add( zdt );
            }
        }
        break;

    case LATER:
        // Start with last day-of-week in month.
        LocalDate lastDowOfMonth = ym.atDay( 1 ).with( TemporalAdjusters.lastInMonth( dow ) );
        // Work our way up through the month, subtracting a week at a time.
        for ( int i = 0 ; i < occurrences ; i++ ) {
            LocalDate ld = lastDowOfMonth.minusWeeks( i );
            ZonedDateTime zdt = ZonedDateTime.of( ld , lt , z );
            if ( YearMonth.from( zdt ).equals( ym ) ) {  // If in same monthâ¦
                moments.add( zdt );
            }
        }
        Collections.sort( moments ); // If you want the list to be in chronological order, sort.  Otherwise in reverse chronological order for this `Mode.LATER`.
        break;

    case VALUE:
        // Get the nth day-of-week in month.
        LocalDate nthDowInMonth = ym.atDay( 1 ).with( TemporalAdjusters.dayOfWeekInMonth( occurrences , dow ) );
        ZonedDateTime zdt = ZonedDateTime.of( nthDowInMonth , lt , z );
        if ( YearMonth.from( zdt ).equals( ym ) ) {  // If in same monthâ¦
            moments.add( zdt );
        }
        break;

    default:  // Defensive programming, testing for unexpected values.
        System.out.println( "ERROR - should not be able to reach this point. Unexpected `Mode` enum value." );
        break;
}
// return `moments` list from your method.
System.out.println( "moments:\n" + moments );

java.time legacy java.util.Date Calendar SimpleDateFormat

Joda-Time maintenance mode java.time

Oracle Tutorial JSR 310

JDBC driver JDBC 4.2 java.sql.*

ThreeTen-Extra Interval YearWeek YearQuarter more

2

0

Emre SavcÄ± 6 年前

public class Main {

    public static void main(String[] args) {
        for (String s : findOccurence("prior", DayOfWeek.WEDNESDAY, 2, "14:00")){
            System.out.println(s);
        }
    }

    public static String[] findOccurence(String mode, DayOfWeek day, int occurrence, String eta) {
        LocalDate now = LocalDate.now();
        LocalDate start = LocalDate.of(now.getYear(), now.getMonth().plus(1), 1);
        LocalDate finish = start.plusDays(start.lengthOfMonth());

        List<LocalDate> dates = Stream.iterate(start, date -> date.plusDays(1))
                .limit(ChronoUnit.DAYS.between(start, finish))
                .filter(d -> d.getDayOfWeek() == day)
                .collect(Collectors.toList());

        String[] formattedEta = eta.split(":");

        if (occurrence > dates.size()) {
            throw new IndexOutOfBoundsException();
        }

        if (mode.equalsIgnoreCase("value")) {

        }
        else if (mode.equalsIgnoreCase("later")) {
            dates = Lists.reverse(dates);
        }

        //later and prior shares common logic

        return dates.stream()
                .limit(occurrence)
                .map(d -> day.toString()
                            + " "
                            + start.getMonth().name()
                            + " "
                            + d.getDayOfMonth()
                            + " "
                            + LocalTime.of(Integer.valueOf(formattedEta[0]), Integer.valueOf(formattedEta[1]), 0)
                            + " "
                            + start.getYear())
                .collect(Collectors.toList())
                .toArray(new String[occurrence]);
    }
}

WEDNESDAY AUGUST 1 14:00 2018
WEDNESDAY AUGUST 8 14:00 2018