Struts 2 Integration
To install the Guice Struts 2 plugin with Struts 2.0.6 or later, simply include guice-struts2-plugin-1.0.jar in your web application's classpath and select Guice as your ObjectFactory implementation in your struts.xml file:
<constant name="struts.objectFactory" value="guice" />
Guice will inject all of your Struts 2 objects including actions and interceptors. You can even scope your actions. You can optionally specify a Module for Guice to install in your struts.xml file:
<constant name="guice.module" value="mypackage.MyModule"/>
If all of your bindings are implicit, you can get away without defining a module at all. A Counting Example
Say for example that we want to count the number of requests in a session. Define a Counter object which will live on the session:
@SessionScoped public class Counter {
- int count = 0;
/** Increments the count and returns the new value. */ public synchronized int increment() {
- return count++;
}
Next, we can inject our counter into an action:
public class Count {
- final Counter counter; @Inject public Count(Counter counter) {
- this.counter = counter;
- return SUCCESS;
- return counter.increment();
}
Then create a mapping for our action in our struts.xml file:
<action name="Count"
class="mypackage.Count">
<result>/WEB-INF/Counter.jsp</result>
</action>
And a JSP to render the result:
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<body>
<h1>Counter Example</h1> <h3><b>Hits in this session:</b>
<s:property value="count"/></h3>
</body>
</html>
We actually made this example more complicated than necessary in an attempt to illustrate more concepts. In reality, we could have done away with the separate Counter object and applied @SessionScoped to our action directly.