How to retrieve Time value from JSP form and"inject it" into db entity object

Question

One of entities in my application has Time member (TIME column in mysql db). I'd like to be able to read that time value from jstl form (just like any other string), so Spring can inject it into that time member using setter (as for other members). Moreover, i'd like to be able to apply some filtering to it, so i can enter both 01:00 and 1:00, and transform it to 01:00.

What Time class should I use? LocalTime, java.sql.Time or any other?

How do I apply pattern to value read? Should I do it in controller, or can I do it inside setter or so?

I've come across multiple ways of reading time from jsp, but i can't seem to find solution for applying pattern.

Answer 1

1. Since you want to save time in a custom format, I suggest you change the column type to a character type (e.g. CHAR or VARCHAR).
2. Next, you can define formats for input (from JSP) and output (to DB) strings using DateTimeFormatter.

Demo:

import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.util.Locale;

public class Main {
    public static void main(String[] args) {
        // Test strings
        String[] times = { "1:00", "01:00", "1:00 pm", "1:00 am", "01:00 am", "01:00 pm" };

        // Define the formatter
        DateTimeFormatter inputFormatter = new DateTimeFormatterBuilder()
                                                .parseCaseInsensitive()
                                                .appendPattern("[h:m a][H:m]")
                                                .toFormatter(Locale.ENGLISH);

        DateTimeFormatter outputFormatter = DateTimeFormatter.ofPattern("HH:mm");

        for (String strTime : times) {
            LocalTime lt = LocalTime.parse(strTime, inputFormatter);

            // String to be saved to the database
            String formattedTime = lt.format(outputFormatter);
            System.out.println(formattedTime);
        }
    }
}

Output:

01:00
01:00
13:00
01:00
01:00
13:00

Notes:

1. You can add more patterns by putting them inside [ ] as shown above.
2. For this demo, I've assumed that you want to save the time in HH:mm (i.e. 24-hour) format.