Java 企业版教程几乎涵盖了您提出的所有主题;不同类型的 bean 类型的目的是什么,如何实现 Web 服务,如何实现身份验证等。
我强烈建议您花时间构建示例应用程序,特别是如果您对 Java Enterprise Edition (Java EE) 完全陌生。建立对核心概念的良好理解非常重要,因为由于构成 Java EE 的技术和标准的广度和深度,一开始可能很难知道应该关注什么。
需要记住的一件事是,虽然 Java EE 肯定会尝试支持最佳实践并支持设计和开发性能和可扩展性良好的安全企业应用程序,但它并没有规定或限制企业应用程序遵循一种特定的协议、数据格式和企业应用程序设计模式。一些协议和格式可以更好地被核心框架实现开箱即用地支持,并且一些选择取决于供应商,但很少有特定的技术选择被锁定在规范中。
To answer some of your specific questions, Java EE has great support for SOAP, but it does not preference nor limit web services to the SOAP protocol. With JAXB and JAX-RS it is just as easy to develop RESTful web services that accept and return XML or JSON, or both. It's up to you to decide whether you need to use SOAP, REST, or another protocol.
It's also your choice whether you want to use frameworks like JAX-RS or explicitly develop Servlets to handle HTTP requests and responses. In many cases, JAX-RS will have everything you need, meaning you'll be able to implement your web services as plain old Java methods with a few annotations without ever having to bother with marshalling and unmarshalling contents and parameters.
Similarly, with JAXB it's up to you whether you want to use WSDL or not. It's great if you have WSDL definitions, but no problem if you don't.
In many cases you will typically maintain state using the Java Persistence Architecture framework (JPA), and access and manipulate such data through stateless session beans. Developers new to Java EE are often tempted to use stateful session beans to maintain state that is better managed in the persistent storage. The tutorial takes you through the different kinds of bean types and their purpose.