KnowForgeStruts 2 Integration
qianmoQ· 更新于 2026-09-23· 阅读 7 分钟· 0 次阅读Struts 2 Integration
Important: The struts2 plugin is only supported up until Guice 6.0. It is not included in Guice 7.0+, because struts2 does not support the jakarta namespaces.
To install the Guice Struts 2 plugin with Struts 2.2 or later, simply include guice-struts2-plugin-<version>.jar in your web application's classpath, create a subclass of GuiceServletContextListener that implements getInjector and adds any servlets and filters (using ServletModule) and the Struts2GuicePluginModule, and a web.xml file that references your GuiceServletContextListener subclass as a listener. For examples, look at the example web.xml and GuiceServletContextListener subclass.
Guice will inject all of your Struts 2 objects including actions and interceptors. You can even scope your actions.
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;
}
public String execute() {
return SUCCESS;
}
public int getCount() {
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.
Struts2 support in earlier versions of Guice
In Guice 1.0, the struts2 extension supports struts 2.0.6 or later, and is included using the guice-struts2-plugin-1.0.jar. The struts2 extension included in Guice 2.0 did not work properly.
You must select Guice as your ObjectFactory implementation in your struts.xml file:
<constant name="struts.objectFactory" value="guice" />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.
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