Overview of This Lesson

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You can use special Thymeleaf objects to perform extra tasks like processing strings, formatting numbers, and working with lists.

Helpful Resources

• Thymeleaf Documentation
• Thymeleaf Tutorial
• Launchcode Thymeleaf Tutorial - a very quick tutorial with a few basics to get you started
• Java Guides: Thymeleaf Tutorial

Thymeleaf Objects

Thymeleaf comes with several utility objects that you can use for common tasks such as working with dates and times, formatting numbers, and string operations. There are several objects, but I've only included the ones you might find useful. Feel free to explore the others in the Thymeleaf documentation and tutorials.

• #dates (tutorial) and #calendars (tutorial) - for performing date/calendar operations

  <div th:text="${#dates.format(myDate, 'dd/MMM/yyy HH:mm')}">format myDate using standard 
  date/time format characters</div>
  <div th:text="|${#dates.hour(apptTime)}: ${#dates.minute(apptTime)}|">you can retrieve 
  pieces of a date/time</div>

• #numbers (tutorial) - for formatting of numbers

  <div th:text="${#numbers.formatCurrency(inv.price)}">always formats as $xx.xx</div>
  <div th:text="${#numbers.formatDecimal(eval.weight,2,1)}">2nd arg = # digits on the left;
  3rd arg = # digits on the right</div>

• #strings (tutorial) - for performing string operations

  <div th:text="${#strings.defaultString(appt.topic, 'no topic')}">displays 'no topic' if 
  appt.topic is empty</div>
  <div th:text="${#strings.toUpperCase(book.title)}">upper-case book title</div>
  <div th:if="${#strings.equalsIgnoreCase(book.author, searchAuth)}">just like String.equalsIgnoreCase(), 
  #strings.equals() works, too</div>

• #arrays (tutorial), #lists (tutorial), and #maps (tutorial) - functions useful when working with arrays, lists, and maps

  <div th:text="${#arrays.length(bookArray)}"># elements in bookArray</div>
  <div th:text="${#lists.size(bookList)}"># elements in bookList</div>
  <li th:each="b : ${#lists.sort(bookList)}">iterate through a sorted list of books 
  (Book must implement Comparable interface)</li>
  <div th:if="${#maps.containsKey(courseMap, 'prog10082')}">courseMap is a Map (like HashMap),
  renders this DIV if the map contains an element with the key 'prog10082'</div>
  <div th:if="${#maps.containsValue(courseMap, java3)}">courseMap is a Map (like HashMap),
  renders this DIV if the map contains an element whose value is the object
  referenced by the variable called 'java3'</div>

Exercises

1. Write the code for a paragraph element that displays the year of a date stored in the model attribute that has the key "today".
2. Write the code for any block element that only renders if a string stored in the model attribute "itemId" contains the value "xx". The elment should display the value in the itemId model attribute in all upper-case letters.
3. Write the code that displays a table only if an array stored in the model attribute "bookList" contains elements.
4. Write the code that displays an unordered list of Inventory objects with a list item for each inventory object in a list stored as the model attribute "inventory". The inventory items should be displayed in sorted order (assume the Inventory bean implements Comparable)