Java Web Services Up and Running 2nd阅读笔记

Java Web Services Up and Running 2nd阅读笔记

快速入门

web service是如何发展起来的？

为了解决开发的易用性，轻量级，语言无关性。

1. XML-RPC 基于HTTP传输，XML格式的文本，轻量级

2. 重量级的Distributed Object Architecture 如J2EE, 基于java RMI (远程方法调用) ， import java.util.List; public interface BenefitsService extends java.rmi.Remote { public List getBenefits(Emp emp) throws RemoteException; }
   client端维护一个stub, 客户端需要服务端一样的POJO类， 使用marshaling/unmarshaling

3. Web Service的简化操作
   客户端和服务端基于HTTP协议交换XML数据，不要求相同的语言实现，你可以是面向对象语言，面向过程函数，或者其他方式。

non-java types ---> convert to  XML ---> Convert to Java， 

为何REST-STYLE SERVICES很流行?**

为了降低逐渐增加的SOAP的复杂性
内容载体更丰富
REST and SOAP are quite different. SOAP is a messaging protocol in which the messages
are XML documents, whereas REST is a style of software architecture for distributed
hypermedia systems, or systems in which text, graphics, audio, and other media are
stored across a network and interconnected through hyperlinks.

HTTP既是传输协议，又是消息系统。所负载的消息通过MIME(Multipurpose Internet Mail Extension) type指定不同的格式，如text/html, application/octet-stream, audio/mpeg3等等

HTTP提供返回状态码表明请求的处理结果

对于Rest风格的web service系统，Client端做两件事:
a) 通过URL命名目标资源
b) 指定verb (HTTP method)

Table 1-2. HTTP verbs and their CRUD operations

HTTP verb	CRUD operation
POST	Create
GET	Read
PUT	Update
DELETE	Delete

The Restful web service APIs include:
• HttpServlet and its equivalents (e.g., JSP scripts)
• JAX-RS, which has various implementations
• Restlet, which is similar in style to JAX-RS
• JAX-WS @WebServiceProvider, which is a relatively low-level API

@GET, @POST @PUT @DELETE

JAW-WS is an API used mostly for SOAP-based services but can be used for REST-style
services as well.

annotation	scope
@WebServiceProvider	for both SOAP/RESTFUL, lower-level API
@WebService	for SOAP (JAX-WS) only
@GET, @POST, @PUT, @DELETE	for JAX-RS/ Restlet