Date Formatting

Part of the Logic & Flow section of Coddy's Java journey. Lesson 58 of 59.

DateTimeFormatter in Java allows you to format dates and times in different patterns. It can be used with LocalDate, LocalTime, and LocalDateTime.

Create a formatter with a specific pattern:

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");

Format a date using the formatter:

LocalDate date = LocalDate.of(2024, 3, 15);
String formatted = date.format(formatter);

After executing the above code, formatted contains:

2024-03-15

Parse a string into a date:

String dateStr = "2024-03-15";
LocalDate date = LocalDate.parse(dateStr, formatter);

Challenge

Easy

Create a method named formatDate that takes three arguments:

A String (dateStr) in format "yyyy-MM-dd"
A String (inputPattern) the pattern of input date
A String (outputPattern) the desired output pattern

The method should:

Parse the input date using the input pattern
Format it using the output pattern
Handle these patterns:
- "basic": "yyyy-MM-dd"
- "long": "MMMM d, yyyy"
- "short": "MM/dd/yy"
- "custom": The actual pattern string

Return messages should be:

If invalid date: return "Invalid date format"
If invalid pattern: return "Invalid pattern"
For success: return the formatted date

Try it yourself

import java.util.Scanner;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;

public class Main {
    public static String formatDate(String dateStr, String inputPattern, String outputPattern) {
        // Write your code here
    }
    
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String dateStr = scanner.nextLine();
        String inputPattern = scanner.nextLine();
        String outputPattern = scanner.nextLine();
        
        System.out.println(formatDate(dateStr, inputPattern, outputPattern));
    }
}