Question

I’m currently running a working Spring + Apache Tiles webapp.
I need to show some example code to explain my intention.

Apache Tiles Configuration:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE tiles-definitions PUBLIC
    "-//Apache Software Foundation//DTD Tiles Configuration 2.1//EN"
    "http://tiles.apache.org/dtds/tiles-config_2_1.dtd">

<tiles-definitions>

    <definition name="baseLayout" template="/WEB-INF/layouts/www_base.jsp" />

    <definition name="home" extends="baseLayout">
        <put-attribute name="body" value="/WEB-INF/views/home.jsp" />
    </definition>

</tiles-definitions>

Example Controller:

@Controller
public class ExampleController {
    @RequestMapping("/index.html")
    public String index(Map<String, Object> map) {
        map.put("hello", "world");
        return "home";
    }
}

This would display www_base.jsp with home.jsp as body. I can use variable ${hello} in www_base.jsp as well as in home.jsp.

But I don’t want to set hello in each Controller method to be able to use it in www_base.jsp on each page.

Is there a way to set global variables for www_base.jsp, e.g. in the constructor of ExampleController?

UPDATE
Example Code using a Map

@Controller
@RequestMapping("/")
public class BlogController {
    @ModelAttribute
    public void addGlobalAttr( Map<String, Object> map ) {
        map.put("fooone", "foo1");
    }

    @RequestMapping("/index.html")
    public String posts(Map<String, Object> map) {
        map.put("foothree", "foo3");
        return "posts";
    }
}

Answer 1

Use a method annotated with @ModelAttribute:

An @ModelAttribute on a method indicates the purpose of that method is
to add one or more model attributes. Such methods support the same
argument types as @RequestMapping methods but cannot be mapped
directly to requests. Instead @ModelAttribute methods in a controller
are invoked before @RequestMapping methods, within the same
controller.

@ModelAttribute methods are used to populate the model with commonly
needed attributes for example to fill a drop-down with states or with
pet types, or to retrieve a command object like Account in order to
use it to represent the data on an HTML form.