Question

Struts2中有一个接口DispatcherListener。文档说

“标记那些想要在init上执行代码的接口 destroy的{{1}}。

但是如何使用这个界面。如果我创建一个实现此接口的类，我应该如何配置它为Struts2？

Answer 1

当Dispatcher被实例化时，它可以在初始化或销毁时向监听器发送通知。参考和代码示例来自here。

简单的用法是通过bean标记通过容器实例化bean，并在init方法中添加自己，并在销毁时将其自身移除，就像ClasspathConfigurationProvider一样。

代码原始只是为了向您展示这个想法

<强> struts.xml

<bean type="com.opensymphony.xwork2.config.PackageProvider" name="myBean" class="jspbean.struts.MyBean" />

<强> MyBean.java

public class MyBean implements ConfigurationProvider, DispatcherListener {
  public MyBean() {
    System.out.println("!!! MyBean !!!");
  }

  @Override
  public void dispatcherInitialized(Dispatcher du) {
    System.out.println("!!! dispatcherInitialized !!!");
  }

  @Override
  public void dispatcherDestroyed(Dispatcher du) {
    System.out.println("!!! dispatcherDestroyed !!!");
  }

  @Override
  public void destroy() {
    System.out.println("!!! destroy !!!");
    Dispatcher.removeDispatcherListener(this);
  }

  @Override
  public void init(Configuration configuration) throws ConfigurationException {
    System.out.println("!!! init !!!");
    Dispatcher.addDispatcherListener(this);
  }

  @Override
  public boolean needsReload() {
    return false;
  }

  @Override
  public void loadPackages() throws ConfigurationException {

  }

  @Override
  public void register(ContainerBuilder builder, LocatableProperties props) throws ConfigurationException {

  }
}

输出：

15:27:50  INFO (org.apache.struts2.spring.StrutsSpringObjectFactory:42) - ... initialized Struts-Spring integration successfully
!!! MyBean !!!
!!! init !!!
jul 18, 2013 3:27:51 PM org.apache.catalina.startup.HostConfig deployDirectory
!!! dispatcherInitialized !!!
[2013-07-18 06:28:11,102] Artifact jspbean:war exploded: Artifact is deployed successfully
INFO: A valid shutdown command was received via the shutdown port. Stopping the Server instance.
INFO: Stopping service Catalina
!!! dispatcherDestroyed !!!

Answer 2

如果您正在使用Spring，那么您可以创建监听器的bean，并在构造函数中将其添加到dispatcherListeners列表。

public YourDispatcherListener () {
  Dispatcher.addDispatcherListener(this);
}

另一种解决方案是创建ServletContextListener，创建您的调度程序侦听器并将其添加到列表中。

如何在Struts 2中使用DispatcherListener

2 个答案: