Spring Boot-Embedded Tomcat-@WebListener，由@ServletComponentScan扫描，添加一个过滤器并获取java.lang.UnsupportedOperationException

假设我们可以使用

@ServletComponentScan

添加带有

@WebListener

、

@WebFilter

等注释的标准servlet组件

在我的例子中，我有一个动态添加过滤器的

@WebListener

：

@WebListener
public class FilterConfigurerListener implements ServletContextListener{

    @Override
    public void contextInitialized(ServletContextEvent sce) {   
        try{
            ...
            ServletContext sc = sce.getServletContext();
            Dynamic rcf = sc.addFilter("myFilter", MyFilter.class);

    @Override
    public javax.servlet.FilterRegistration.Dynamic addFilter(
            String filterName, Class<? extends Filter> filterClass) {
        throw new UnsupportedOperationException(
                sm.getString("noPluggabilityServletContext.notAllowed"));
    }

addFilter（）

调用引发以下异常：

java.lang.UnsupportedOperationException: Section 4.4 of the Servlet 3.0 specification does not permit this method to be called from a ServletContextListener that was not defined in web.xml, a web-fragment.xml file nor annotated with @WebListener
    at org.apache.catalina.core.StandardContext$NoPluggabilityServletContext.addFilter(StandardContext.java:6639)
    at com.whatever.FilterConfigurerListener.contextInitialized(FilterConfigurerListener.java:44)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4743)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5207)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1419)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:748)

我的Spring Boot应用程序的注释如文档中所述：

@ServletComponentScan(basePackageClasses=FilterConfigurerListener.class)
@SpringBootApplication
public class MySpringBootApplication {

查看一下

org.apache.catalina.core.StandardContext

，我可以看到此实现不允许添加过滤器：

@WebListener
public class FilterConfigurerListener implements ServletContextListener{

    @Override
    public void contextInitialized(ServletContextEvent sce) {   
        try{
            ...
            ServletContext sc = sce.getServletContext();
            Dynamic rcf = sc.addFilter("myFilter", MyFilter.class);

    @Override
    public javax.servlet.FilterRegistration.Dynamic addFilter(
            String filterName, Class<? extends Filter> filterClass) {
        throw new UnsupportedOperationException(
                sm.getString("noPluggabilityServletContext.notAllowed"));
    }

@覆盖
public javax.servlet.FilterRegistration.Dynamic addFilter(
String filterName，Class为什么不在您的Spring Boot应用程序中作为bean添加过滤器呢？因为
FilterConfigurerListener
包含一些可重用的逻辑。它是Spring Boot应用程序和普通JEE应用程序中都使用的库的一部分。我怀疑自动检测不会起作用，您可能会
EmbeddedServletContainerCustomizer
将其添加到容器中，而不是自动检测它。您可能需要将其包装在
ServletContainerInitializer
中以执行它。对于您的spring应用程序，可以扩展
FilterConfigurerListener
，以便以“spring方式”使用它并完成吗？