Impara Combining Date and Table Formatting | Parsing Dates and Formatting Tables

When you need to generate professional-looking reports in Java, combining date formatting with table output is a common requirement. By using LocalDate and formatting methods like DateTimeFormatter alongside String.format(), you can create tables that display dates, numbers, and strings in a clean, organized manner. This approach allows you to align columns and ensure that every type of data—whether it's a date, a name, or a numeric value—appears consistent and readable in your output.

Main.java


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package com.example;

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

public class Main {
    public static void main(String[] args) {
        String[] eventNames = {"Conference", "Workshop", "Meetup"};
        LocalDate[] eventDates = {
            LocalDate.of(2024, 7, 10),
            LocalDate.of(2024, 8, 5),
            LocalDate.of(2024, 9, 15)
        };

        DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("MMM dd, yyyy");

        System.out.printf("%-15s | %-15s%n", "Event", "Date");
        System.out.println("-------------------------------");
        for (int i = 0; i < eventNames.length; i++) {
            String formattedDate = eventDates[i].format(dateFormatter);
            System.out.printf("%-15s | %-15s%n", eventNames[i], formattedDate);
        }
    }
}

When mixing different data types like dates, numbers, and strings in a table, it is important to apply formatting consistently to each type. Use DateTimeFormatter for dates to ensure a uniform appearance, and String.format() or printf to control column widths and alignment for all values. Set clear column widths and choose patterns that suit your data, so your table remains readable even as the content changes. Always convert complex data types—such as LocalDate or numeric values—into strings that fit the table's layout before printing. This approach prevents misalignment and keeps your output looking professional.

Main.java


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// File: EventReport.java
package com.example;

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

public class Main {
    public static void main(String[] args) {
        String[] eventNames = {"Conference", "Workshop", "Meetup"};
        LocalDate[] eventDates = {
            LocalDate.of(2024, 7, 10),
            LocalDate.of(2024, 8, 5),
            LocalDate.of(2024, 9, 15)
        };
        int[] attendance = {150, 80, 40};

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

        System.out.printf("%-15s | %-12s | %10s%n", "Event", "Date", "Attendance");
        System.out.println("---------------------------------------------------");
        for (int i = 0; i < eventNames.length; i++) {
            String formattedDate = eventDates[i].format(dateFormatter);
            System.out.printf("%-15s | %-12s | %10d%n", eventNames[i], formattedDate, attendance[i]);
        }
    }
}

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Sezione 3. Capitolo 5

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Main.java


              12345678910111213141516171819202122232425
            
package com.example;

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

public class Main {
    public static void main(String[] args) {
        String[] eventNames = {"Conference", "Workshop", "Meetup"};
        LocalDate[] eventDates = {
            LocalDate.of(2024, 7, 10),
            LocalDate.of(2024, 8, 5),
            LocalDate.of(2024, 9, 15)
        };

        DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("MMM dd, yyyy");

        System.out.printf("%-15s | %-15s%n", "Event", "Date");
        System.out.println("-------------------------------");
        for (int i = 0; i < eventNames.length; i++) {
            String formattedDate = eventDates[i].format(dateFormatter);
            System.out.printf("%-15s | %-15s%n", eventNames[i], formattedDate);
        }
    }
}

Main.java


              123456789101112131415161718192021222324252627
            
// File: EventReport.java
package com.example;

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

public class Main {
    public static void main(String[] args) {
        String[] eventNames = {"Conference", "Workshop", "Meetup"};
        LocalDate[] eventDates = {
            LocalDate.of(2024, 7, 10),
            LocalDate.of(2024, 8, 5),
            LocalDate.of(2024, 9, 15)
        };
        int[] attendance = {150, 80, 40};

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

        System.out.printf("%-15s | %-12s | %10s%n", "Event", "Date", "Attendance");
        System.out.println("---------------------------------------------------");
        for (int i = 0; i < eventNames.length; i++) {
            String formattedDate = eventDates[i].format(dateFormatter);
            System.out.printf("%-15s | %-12s | %10d%n", eventNames[i], formattedDate, attendance[i]);
        }
    }
}

Tutto è chiaro?

Grazie per i tuoi commenti!

Sezione 3. Capitolo 5

Combining Date and Table Formatting

1. How can you ensure dates are consistently formatted in a table?

2. What is a good approach for mixing different data types in a formatted table?

3. Why is it beneficial to use both DateTimeFormatter and String.format() together?

Combining Date and Table Formatting

1. How can you ensure dates are consistently formatted in a table?

2. What is a good approach for mixing different data types in a formatted table?

3. Why is it beneficial to use both DateTimeFormatter and String.format() together?