我正在使用spring-boot 2.0和Spring security 5.0+创建一个基于oauth2.0的授权服务器。当Tomcat启动时，即使spring-security-oauth2-client位于如下类路径中，我也会收到以下错误。

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.security.oauth.boot</groupId>
<artifactId>spring-security-oauth2-autoconfigure</artifactId>
<version>2.0.0.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.security.oauth</groupId>
<artifactId>spring-security-oauth2</artifactId>
<version>2.3.0.RELEASE</version>
</dependency> 
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-oauth2-client</artifactId>
</dependency>

Caused by: java.lang.ClassNotFoundException: org.springframework.security.oauth2.client.web.OAuth2LoginAuthenticationFilter
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[?:1.8.0_111]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_111]
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) ~[?:1.8.0_111]
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_111]
    at org.springframework.security.config.annotation.web.builders.HttpSecurity.oauth2Login(HttpSecurity.java:991) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at com.oauth.oauthserver.DemoSecurityConfig.configure(DemoSecurityConfig.java:39) ~[classes/:?]
    at org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter.getHttp(WebSecurityConfigurerAdapter.java:230) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter.init(WebSecurityConfigurerAdapter.java:321) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter.init(WebSecurityConfigurerAdapter.java:92) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at com.oauth.oauthserver.DemoSecurityConfig$$EnhancerBySpringCGLIB$$34fbb215.init(<generated>) ~[classes/:?]
    at org.springframework.security.config.annotation.AbstractConfiguredSecurityBuilder.init(AbstractConfiguredSecurityBuilder.java:371) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.security.config.annotation.AbstractConfiguredSecurityBuilder.doBuild(AbstractConfiguredSecurityBuilder.java:325) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.security.config.annotation.AbstractSecurityBuilder.build(AbstractSecurityBuilder.java:41) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration.springSecurityFilterChain(WebSecurityConfiguration.java:104) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration$$EnhancerBySpringCGLIB$$581ced26.CGLIB$springSecurityFilterChain$4(<generated>) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration$$EnhancerBySpringCGLIB$$581ced26$$FastClassBySpringCGLIB$$3be2fd03.invoke(<generated>) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228) ~[spring-core-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:361) ~[spring-context-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration$$EnhancerBySpringCGLIB$$581ced26.springSecurityFilterChain(<generated>) ~[spring-security-config-5.0.4.RELEASE.jar:5.0.4.RELEASE]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_111]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_111]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_111]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_111]
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:579) ~[spring-beans-5.0.5.RELEASE.jar:5.0.5.RELEASE]
    ... 20 more

此异常的原因可能是什么？
谢谢五十铃