如何使用Spring将依赖项注入HttpSessionListener？

Question

如何使用Spring和没有调用将依赖项注入HttpSessionListener,如context.getBean("foo-bar")？

Answer 1

由于Servlet 3.0 ServletContext具有"addListener"方法,因此您可以通过以下代码添加侦听器,而不是在web.xml文件中添加侦听器:

@Component
public class MyHttpSessionListener implements javax.servlet.http.HttpSessionListener, ApplicationContextAware {

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        if (applicationContext instanceof WebApplicationContext) {
            ((WebApplicationContext) applicationContext).getServletContext().addListener(this);
        } else {
            //Either throw an exception or fail gracefully, up to you
            throw new RuntimeException("Must be inside a web application context");
        }
    }           
}

这意味着您可以正常注入"MyHttpSessionListener",只需在应用程序上下文中存在bean将导致监听器向容器注册

Answer 2

您可以HttpSessionListener在Spring上下文中将您声明为bean,并将委托代理注册为实际的侦听器web.xml,如下所示:

public class DelegationListener implements HttpSessionListener {
    public void sessionCreated(HttpSessionEvent se) {
        ApplicationContext context = 
            WebApplicationContextUtils.getWebApplicationContext(
                se.getSession().getServletContext()
            );

        HttpSessionListener target = 
            context.getBean("myListener", HttpSessionListener.class);
        target.sessionCreated(se);
    }

    ...
}