3

Struts2中有一个接口DispatcherListener。文档说

“一个接口,用于标记那些想要在init和 上执行代码destroy的人Dispatcher。”

但是如何使用这个接口。如果我创建一个实现这个接口的类,我应该如何将它配置为 Struts2?

4

2 回答 2

2

当 aDispatcher被实例化时,它可以在初始化或销毁时向侦听器发送通知。参考和代码示例来自这里

简单的用法是容器通过bean标签实例化一个 bean,并将它们自己添加到init方法中,并在销毁时将它们自己移除,就像ClasspathConfigurationProvider.

代码是原始的,只是为了向您展示这个想法

struts.xml

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

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 !!!
于 2013-07-17T13:15:07.877 回答
1

如果您使用的是 Spring,那么您可以创建侦听器的 bean,并在构造函数中将其添加到dispatcherListeners列表中。

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

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

于 2013-07-17T13:31:59.120 回答