java - Thymeleaf construct URL with variable

Question

I have the following code setting a variable in my controller:

model.set("type", type);

In the thymeleaf view I want to construct a form with action url:

/mycontroller/{type}

Any ideas how to achieve this? I've read thymeleaf documentation with no luck.

Answer 1

As user482745 suggests in the comments (now deleted), the string concatenation I previously suggested

<form th:action="@{/mycontroller/} + ${type}">

will fail in some web contexts.

Thymeleaf uses LinkExpression that resolves the @{..} expression. Internally, this uses HttpServletResponse#encodeURL(String). Its javadoc states

For robust session tracking, all URLs emitted by a servlet should be run through this method. Otherwise, URL rewriting cannot be used with browsers which do not support cookies.

In web applications where the session tracking is done through the URL, that part will be appended to the string emitted for @{..} before the ${..} is appended. You don't want this.

Instead, use path variables as suggested in the documentation

You can also include parameters in the form of path variables similarly to normal parameters but specifying a placeholder inside your URL’s path:

<a th:href="@{/order/{id}/details(id=3,action='show_all')}">

So your example would look like

<form th:action="@{/mycontroller/{path}(path=${type})}"> //adding ending curly brace