DelegatingFilterProxyRegistrationBean
package org.springframework.boot.web.servlet;
import javax.servlet.Filter;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.util.Assert;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.filter.DelegatingFilterProxy;
/**
* A ServletContextInitializer to register DelegatingFilterProxys in a
* Servlet 3.0+ container. Similar to the ServletContext#addFilter(String, Filter)
* registration features provided by ServletContext but with a Spring Bean
* friendly design.
*
* The bean name of the actual delegate Filter should be specified using the
* targetBeanName constructor argument. Unlike the FilterRegistrationBean,
* referenced filters are not instantiated early. In fact, if the delegate filter bean is
* marked @Lazy it won't be instantiated at all until the filter is called.
*
* Registrations can be associated with #setUrlPatterns URL patterns and/or
* servlets (either by #setServletNames name or via a
* #setServletRegistrationBeans ServletRegistrationBeans. When no URL pattern or
* servlets are specified the filter will be associated to '/*'. The targetBeanName will
* be used as the filter name if not otherwise specified.
*
* @author Phillip Webb
* @since 1.4.0
* @see ServletContextInitializer
* @see ServletContext#addFilter(String, Filter)
* @see FilterRegistrationBean
* @see DelegatingFilterProxy
*/
public class DelegatingFilterProxyRegistrationBean extends AbstractFilterRegistrationBean
implements ApplicationContextAware {
private ApplicationContext applicationContext;
private final String targetBeanName;
/**
* Create a new DelegatingFilterProxyRegistrationBean instance to be
* registered with the specified ServletRegistrationBeans.
* @param targetBeanName name of the target filter bean to look up in the Spring
* application context (must not be null).
* @param servletRegistrationBeans associate {@link ServletRegistrationBean}s
*/
public DelegatingFilterProxyRegistrationBean(String targetBeanName,
ServletRegistrationBean... servletRegistrationBeans) {
super(servletRegistrationBeans);
Assert.hasLength(targetBeanName, "TargetBeanName must not be null or empty");
this.targetBeanName = targetBeanName;
setName(targetBeanName);
}
@Override
public void setApplicationContext(ApplicationContext applicationContext)
throws BeansException {
this.applicationContext = applicationContext;
}
protected String getTargetBeanName() {
return this.targetBeanName;
}
@Override
public Filter getFilter() {
return new DelegatingFilterProxy(this.targetBeanName,
getWebApplicationContext()) {
@Override
protected void initFilterBean() throws ServletException {
// Don't initialize filter bean on init()
}
};
}
private WebApplicationContext getWebApplicationContext() {
Assert.notNull(this.applicationContext, "ApplicationContext be injected");
Assert.isInstanceOf(WebApplicationContext.class, this.applicationContext);
return (WebApplicationContext) this.applicationContext;
}
}