您需要确保正确编译了类文件并将其放置在webapp的运行时类路径中.例如.在WAR中为/WEB-INF/classes/fr/epsi/utils/ConstantsPages.class.

You need to make sure that the class file is properly compiled and placed in webapp's runtime classpath. E.g. as /WEB-INF/classes/fr/epsi/utils/ConstantsPages.class inside the WAR.

此异常表明并非如此.确实没有其他原因.如果您使用的是IDE，请确保该类文件位于Web项目的Java源文件夹中，并且已清理，重建和重新部署了该项目并重新启动了服务器.

This exception says that it is not. There's really no other cause. If you're using an IDE, make sure that the class file is inside Java source folder of the web project and that you've cleaned, rebuilt and redeployed the project and restarted the server.