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手动设置日期和时间 - java

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我试图让客户设定他们想要预约的日期和时间 . 我已经完成的代码在保存时会在文本文件中创建大量文本,并在您尝试再次加载时崩溃 .

这是我添加预订的代码:

public static List<Reservation> addReservations(List<Reservation> reservations, List<Customer> customers) {
    int newReservationId = Reservation.getNumberOfReservations() + 1;
    String startString = readString("Enter Reservation date");
    SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
    Date date = null;
    try {
        date = sdf.parse(startString);
    } catch (ParseException ex) {
        Logger.getLogger(ProjectIncrement5.class.getName()).log(Level.SEVERE, null, ex);
    }
    Calendar dateTime = Calendar.getInstance();
    dateTime.setTime(date);

    listCustomers(customers, reservations);
    int reservationCustomerId = readInt("Enter Customer Id", Customer.getNumberOfCustomers(), 1);
    Customer reservationCustomer = customers.get(reservationCustomerId - 1);
    Reservation res = new Reservation(newReservationId, dateTime, reservationCustomer);
    reservations.add(res);
    return reservations;
}

预订舱位:

public class Reservation {

private int reservationId;
private Calendar dateTime;
private Customer customer;


private static int numberOfReservations = 0;

public Reservation() {
    this.reservationId = 0;
    this.dateTime = null;
     this.customer = null;


    numberOfReservations++;
}

public Reservation(int reservationId, Calendar dateTime, Customer customer) {
    this.reservationId = reservationId;
    this.dateTime = dateTime;
      this.customer = customer;

    numberOfReservations++;
}

public static int getNumberOfReservations() {
    return numberOfReservations;
}

public int getReservationId() {
    return reservationId;
}

public void setreservationId(int reservationId) {
    this.reservationId = reservationId;
}

public Calendar getDateTime() {
    return dateTime;
}

    public Customer getCustomer()
{
    return customer;
}

public void setCustomer(Customer customer)
{
    this.customer = customer;
}     



public String setDateTime() {
    SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
    String dateString = formatter.format(this.dateTime.getTime());
    return dateString;
}

@Override
public String toString() {
    return "Reservation id: " + getReservationId() + ", "
            + "Date/Time " + setDateTime() +
    "customer: " + getCustomer();

}
}

这是保存到文本文件中导致错误的原因:

1:java.util.GregorianCalendar [time = 851385600000,areFieldsSet = true,areAllFieldsSet = true,lenient = true,zone = sun.util.calendar.ZoneInfo [id =“Europe / London”,offset = 0,dstSavings = 3600000 ,useDaylight =真,过渡= 242,lastRule = java.util.SimpleTimeZone中[ID =欧洲/伦敦,偏移= 0,dstSavings = 3600000,useDaylight =真,startYear = 0,STARTMODE = 2,startMonth = 2,朝九特派= - 1,startDayOfWeek = 1,开始时间= 3600000,startTimeMode = 2,endMode = 2,endMonth = 9,endday指定= -1,一个endDayOfWeek = 1,结束时间= 3600000,endTimeMode = 2]],Firstdayofweek可= 2,minimalDaysInFirstWeek = 4,ERA = 1,YEAR = 1996,月= 11,WEEK_OF_YEAR = 52,WEEK_OF_MONTH = 4,DAY_OF_MONTH = 24,DAY_OF_YEAR = 359,DAY_OF_WEEK = 3,DAY_OF_WEEK_IN_MONTH = 4,AM_PM = 0,HOUR = 0,HOUR_OF_DAY = 0,MINUTE = 0 ,SECOND = 0,微差= 0,ZONE_OFFSET = 0,DST_OFFSET = 0]:4:<

我认为在获取日历实例时会出现错误,但我不确定如何更简单地解决这个问题 . 有人可以帮忙吗?

3 回答

  • 1

    问题是您将 Calendar.toString() 而不是实际日期存储到文本文件中 .

    看看你发布的内容:

    firstDayOfWeek = 2,minimalDaysInFirstWeek = 4,ERA = 1,YEAR = 1996,MONTH = 11,WEEK_OF_YEAR = 52,WEEK_OF_MONTH = 4,DAY_OF_MONTH = 24,DAY_OF_YEAR = 359,DAY_OF_WEEK = 3,DAY_OF_WEEK_IN_MONTH = 4,AM_PM = 0,HOUR = 0,HOUR_OF_DAY = 0,MINUTE = 0,SECOND = 0,微差= 0,ZONE_OFFSET = 0,DST_OFFSET = 0]

    这似乎是一个正确的日期 . 我会说更多,这似乎是一个非常完整的日期,有很多信息不会??? ;)


    我不知道该日期应该如何存储,但是,例如,如果您想以 dd/MM/yyyy 格式存储日期,请使用以下代码行来检查它是否是有效日期(您已在代码中执行此操作) .

    SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
    date = sdf.parse(startString);
    

    检查完毕后,如果 startString 有效,则无需创建任何 Calendar 实例 write startString to the text file .


    更新:

    所以在我的Reservation类中,而不是:private Calendar dateTime我会把它拿出来,只有:private String startString?

    不 . 这个想法是:

    • 在Java类中,存储在特定的 Object 中( Calendar 没问题,但是日期也是如此)

    • 在文本文件中,通过 String 发送人类可读日期 .

    抱歉,我可以't be more specific, I can' t执行你的代码,因为很多部分都缺失了( CustomerreadIntlistCustomers 等......) .

  • 1

    我接受Jordi Castilla的答案,也想告诉别人做同样的选择 . 在这里,您使用 Calendar.toString() 方法将日期和时间保存到文件,而您可以使用以下代码

    DateFormat df = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
    String stringToFile = df.format(date);//you can send this string to the file which you want to store the Date & Time
    
  • 1

    避免遗留日期时间类

    现代方法使用java.time类 . 避免麻烦,混乱和设计不佳的旧遗留日期时间类,如 Calendar .

    LocalDate

    收集日期部分 . 如果输入错误,请 grab 任何DateTimeParseException .

    DateTimeFormatter f = DateTimeFormatter.ofPattern( "dd/MM/uuuu" ) ;
    try {
        LocalDate ld = LocalDate.parse( input , f ) ;
    } catch ( DateTimeParseException e ) {
        …
    }
    

    好像你没有明确跟踪时间 . 所以 LocalDate 类就足够了 .

    ISO 8601

    将数据序列化为文本文件时,应使用标准ISO 8601格式 . 这些格式设计实用且明确,易于通过机器解析,易于跨文化阅读,并且不会假设英语熟练 .

    在解析和生成字符串时,java.time类在默认情况下使用标准格式 . 只需调用 toString 即可生成 .

    String output = ld.toString() ;  // Ex: 2017-01-23
    

    关于java.time

    java.time框架内置于Java 8及更高版本中 . 这些类取代了麻烦的旧legacy日期时间类,如java.util.DateCalendarSimpleDateFormat .

    现在位于maintenance modeJoda-Time项目建议迁移到java.time类 .

    要了解更多信息,请参阅Oracle Tutorial . 并搜索Stack Overflow以获取许多示例和解释 . 规格是JSR 310 .

    从哪里获取java.time类?

    ThreeTen-Extra项目使用其他类扩展了java.time . 该项目是未来可能添加到java.time的试验场 . 您可以在这里找到一些有用的类,例如IntervalYearWeekYearQuartermore .

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