您似乎添加了对 Paypal 库的依赖，但未在您的项目中包含该库:

It looks like you added a dependency on a Paypal library but did not include that library in your project:

Caused by: java.lang.ClassNotFoundException: com.paypal.exception.SSLConfigurationException

我不确定是哪个 jar，但很可能是 paypal-core.jar.尝试将其添加到 WEB-INF/lib 下.

I'm not sure which jar, but it is most likely paypal-core.jar. Try adding it under WEB-INF/lib.