日期作为用户输入使用我自己的日期 class

Question

I'm developing an application, and in there I have to take the date from the user, and it's only date, time is not required. And I was asked to use a Date class to represent the date. But I don't have any idea on how to get the date from the user as a normal input using scanner class.

The date class is shown below, so how can I get the input as a date?

I'm new to programming so please help me to solve this issue.

public class Date {

    private int day;
    private int month;
    private int year;

    public Date(int day, int month, int year) {
        this.day = day;
        this.month = month;
        this.year = year;
    }

    public int getDay() {
        return day;
    }

    public void setDay(int day) {
        this.day = day;
    }

    public int getMonth() {
        return month;
    }

    public void setMonth(int month) {
        this.month = month;
    }

    public int getYear() {
        return year;
    }

    public void setYear(int year) {
        this.year = year;
    }

    @Override
    public String toString() {
        return "Date{" +
                "day=" + day +
                ", month=" + month +
                ", year=" + year +
                '}';
    }
}

This is an assignment, and it asks us to implement a Date class like this, and it asks us to avoid using any predefined libraries in Java.

Answer 1

java.time.LocalDate

We have a class for that: LocalDate . Do not reinvent the wheel.

And be aware that date-time handling is surprisingly tricky work — do not attempt roll-your-own solutions. Always use the industry-leading java.time classes.

LocalDate ld = LocalDate.of( 2021 , 1 , 23 ) ;  // January 23, 2021.
String output = ld.toString() ;

2021-01-23

In a console app, using the Scanner class, ask the user to input a date in ISO 8601 format YYYY-MM-DD.

LocalDate ld = LocalDate.parse( "2021-01-23" ) ;

Or, ask for the year, month, and day inputs separately. Parse each as an integer , and pass the three int values to LocalDate.of as seen above.

Tips:

• Organize your thinking and code to work with greater scope first, and detailed scope later. So year-month-day rather than day-month-year.
• Learn about ISO 8601 standard for formatting date-time values as text when exchanging data.
• Study the java.time tutorial by Oracle .

Answer 2

I understand that this is homework and that you are not allowed to use LocalDate from the standard library (as one would unconditionally do in production code).

Options include (and are not limited to):

1. Read day of month, month and year as three numbers in turn using three calls to Scanner.nextInt() . Pass the three numbers to your Date constructor.
2. Read the date as for example 29-05-2020 from the user using either Scanner.next() or Scanner.nextLine() . Split at hyphens. Parse each number to an int using Integer.parseInt() . Pass the three parsed numbers to the constructor.

Doc links:

• String.split()
• Integer.parseInt()