How to format Dates in Thymeleaf

Question

I've tried this:

<p class="post-date">
                    <time datetime="2023-01-01" th:text="${#temporals.format(item.getCreatedDate(), 'dd-MM-yyyy HH:mm')}">Oct 5, 2023</time>
                  </p>

where createdDate is a java.util.Date

but I am getting this error:

2024-03-30 17:15:58.620 ERROR [] o.a.c.c.C.[.[.[.[dispatcherServlet]@log(175) - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed: org.thymeleaf.exceptions.TemplateProcessingException: Exception evaluating SpringEL expression: "#temporals.format(item.getCreatedDate(), 'dd-MM-yyyy HH:mm')" (template: "blog-details" - line 109, col 49)] with root cause
org.springframework.expression.spel.SpelEvaluationException: EL1004E: Method call: Method format(java.sql.Timestamp,java.lang.String) cannot be found on type org.thymeleaf.expression.Temporals
    at org.springframework.expression.spel.ast.MethodReference.findAccessorForMethod(MethodReference.java:237)
    at org.springframework.expression.spel.ast.MethodReference.getValueInternal(MethodReference.java:147)
    at org.springframework.expression.spel.ast.MethodReference$MethodValueRef.getValue(MethodReference.java:400)

Answer 1

How about trying this one?

<p class="post-date">
  <time datetime="2023-01-01" th:text="${#dates.format(item.getCreatedDate(), 'dd-MM-yyyy HH:mm')}">Oct 5, 2023</time>
</p>

Explaination:

I saw that the error said the method format of org.thymeleaf.expression.Temporals does not have the prototype of (java.sql.Timestamp, java.lang.String). So I can understand that your item.getCreatedDate() is java.sql.Timestamp class:

package java.sql;

public class Timestamp extends java.util.Date {
   ...
}

This class is extends of java.util.Date, so you can use org.thymeleaf.expression.Dates instead:

package org.thymeleaf.expression;

public final class Dates {
    public String format(final Date target, final String pattern) {
       ...
    }
}

Answer 2

Your method item.getCreatedDate() returns an Instant.

This means a few things:

• That's a horrible name. You really should rename that method. That, or, make it return a LocalDate instead, then the name is fine. dates aren't timestamps. Confusion in what kind of temporal concept is being returned is pernicious: Many places allow implicit conversion between types that cannot actually be implicitly converted, resulting in bugs. The kinds of bugs you don't find with tests because they only occur during timezone or daylight saving time mismatches.
• temporals can't format Instant because you're not supposed to: Instants are a moment in time, as the universe measures it: It is not meant to represent, interact, or be suitable for any operation that is based on human reckoning of time (days/months/years/hours/timezones: That's human reckoning. 'millis since epoch', that's computer reckoning). For example, Instants do not encode a timezone at all. They just encode a moment in time. Hence, it is not possible to render it in human terms! To do that, you must first have a timezone; "What month is that instant in time in?" cannot be answered. Only questions like: "What month is that instant in time in... in Amsterdam?" - that can be answered. You must specify a timezone for it to do its job - which you do by converting your Instant to e.g. a ZonedDateTime. That does contain all required info to render it in human reckoning terms, and, indeed, temporals's format can deal with ZDTs (or LocalDateTime instances, your choice) just fine.

Either fix your getCreatedDate() method to return something more appropriate for the job, or, convert the Instant that it returns into a ZDT using:

.getCreatedInstant().atZone(ZoneId.of("Europe/Amsterdam"));

// or
.getCreatedInstant().atZone(ZoneOffset.UTC);