How to set thymeleaf th:field value from other variable

Question

I have a simple text input field where i have to set default value from one object and save its final value in other. The following code is not working.

<div th:object="${form}">
    <input class="form-control"
           type="text"
           th:value="${client.name}"  //this line is ignored
           th:field="*{clientName}"/>
</div>

form is DTO object and client is Entity object from database.

What is the correct way to solve this situation?

By not working I mean - lets say that initial values are client.name="Foo" and form.clientName=null. I need that input field display value is "Foo" and after form submission form.clientName value to become "Foo". But the input field displays nothing and on submission form.clientName value still is null;

If anyone is interested, solved this issue using following structure (found the answer in another question).

th:attr="value = ${client.name}"

Solution 1

You could approach this method.

Instead of using th:field use html id & name. Set value using th:value

<input class="form-control"
           type="text"
           th:value="${client.name}" id="clientName" name="clientName" />

Hope this will help you

Solution 2

The correct approach is to use preprocessing

For example

th:field="*{__${myVar}__}"

Solution 3

If you don't have to come back on the page with keeping form's value, you can do that :

<form method="post" th:action="@{''}" th:object="${form}">
    <input class="form-control"
           type="text"
           th:field="${client.name}"/>

It's some kind of magic :

• it will set the value = client.name
• it will send back the value in the form, as 'name' field. So you would have to change your form field, 'clientName' to 'name'

If you matter keeping you form's input values, like a back on the page with an user input mistake, then you will have to do that :

<form method="post" th:action="@{''}" th:object="${form}">
    <input class="form-control"
           type="text"
           th:name="name"
           th:value="${form.name != null} ? ${form.name} : ${client.name}"/>

That means :

• The form field name is 'name'
• The value is taken from the form if it exists, else from the client bean. Which matches the first arrival on the page with initial value, then the forms input values if there is an error.

Without having to map your client bean to your form bean. And it works because once you submitted the form, the value arn't null but "" (empty)

Comments

[Avery]

Define "is not working". What exactly is happening and what should be happening?

[geoand]

Why not populate the model with default value - thus moving logic away from the template and into the controller where it is probably better suited?

[ziuu]

I think i answered simillar problem here stackoverflow.com/questions/25808433/…

[Justin Smith]

Pointing out that this will ignore the bean binding.

[Antoniossss]

So in general this is how-not-to-do things.

[want2learn]

@JustinSmith Can you elaborate why this solution is not a correct way.

[Justin Smith]

This was a while ago, so it may no longer apply or be relevant, but to elaborate, th:value will set the value attribute of the input element. It does not bind the form to the bean, so if you change that field, then submit, the form data will ignore the binding. I wound up using the th:field attribute, and setting a default value from the controller.

[Tamb]

This is incorrect, it totally voids the effect of binding values

[RiZKiT]

For more informations see thymeleaf.org/doc/tutorials/3.0/…