很多人在專案中使用Webservice，只是知道如何釋出Webservice，如何呼叫Webservice，但真要論其來龍去脈，還真不一定清楚。

一切一切還要從我們偉大的sun公司規範說起。

JAVA 中共有三種WebService 規範，分別是JAXM&SAAJ、JAX-WS（JAX-RPC）、JAX-RS。

下面來分別簡要的介紹一下這三個規範。針對JDK 1.6以下版本，新的還沒研究過

(1.)JAX-WS：

JAX-WS（Java API For XML-WebService），JDK1.6 自帶的版本為JAX-WS2.1，其底層支持為JAXB。早期的基於SOAP 的JAVA 的Web 服務規範JAX-RPC（Java API For 

(2.)JAXM&SAAJ：

JAXM（JAVA API For XML Message）主要定義了包含了傳送和接收訊息所需的API，相當於Web 服務的伺服器端，其API 位於javax.messaging.*包，它是JAVA EE 的可選包，因此你需要單獨下載。
SAAJ（SOAP With Attachment API For Java，JSR 67）是與JAXM 搭配使用的API，為構建SOAP 包和解析SOAP 包提供了重要的支援，支援附件傳輸，它在伺服器端、客戶端都需要使用。這裡還要提到的是SAAJ 規範，其API 位於javax.xml.soap.*包。

JAXM&SAAJ 與JAX-WS 都是基於SOAP 的Web 服務，相比之下JAXM&SAAJ 暴漏了SOAP更多的底層細節，編碼比較麻煩，而JAX-WS 更加抽象，隱藏了更多的細節，更加面向物件，實現起來你基本上不需要關心SOAP 的任何細節。那麼如果你想控制SOAP 訊息的更多細節，可以使用JAXM&SAAJ。

(3.)JAX-RS：
JAX-RS 是JAVA 針對REST(Representation State Transfer)風格制定的一套Web 服務規範，由於推出的較晚，該規範（JSR）並未隨JDK1.6 一起發行，你需要到JCP （Java Community Process) 上單獨下載JAX-RS 規範的介面，其API 位於javax.ws.rs.*包。

對AXIS沒有太大發言權，因為用得少，這裡還是說一點關於CXF的吧。（參考官方文件）

Apache CXF is an open source services framework.CXF helps you build and develop services using frontend programming APIs, likeJAX-WS and JAX-RS. These services can speak a variety of protocols such asSOAP, XML/HTTP, RESTful HTTP, or CORBA and work over a variety of transportssuch as HTTP, JMS or JBI.

如果你想在maven中使用cxf，那麼要在pom中宣告maven依賴。

<dependency>

                    <groupId>org.apache.cxf</groupId>

                    <artifactId>cxf-distribution-manifest</artifactId>

                    <version>2.5.9</version>

                    <scope>provided</scope>

</dependency>

最後說下，Cxf_home 2.5.9版本的lib下jar的作用：

The following jars are required for all CXFusage:

- cxf.jar

- commons-logging.jar

- geronimo-activation.jar (Or the Sunequivalent) [6]

- geronimo-annotation.jar (Or the Sunequivalent) [6]

- geronimo-javamail.jar (Or the Sunequivalent) [6]

 (MAY be able to remove javamail if you don't use any MTOM/SAAJ typethings)

- geronimo-stax-api.jar (Or the Sunequivalent) [6]

- neethi.jar

- jaxb-api.jar  [6]

- jaxb-impl.jar (this is a [6] for normalruntime, but is required for

                 tooling and the dynamicclients)

- XmlSchema.jar

- woodstox-core-asl.jar  [6] or another StAX implementation

- stax2-api-3.0.1.jar [6] for woodstoxabove

- wsdl4j.jar

The following jars are required for XMLcatalog support:

- xml-resolver.jar

For Java2WSDL and WSDL2Java:

- The above jars

- jaxb-xjc.jar

- velocity.jar

- commons-collections.jar

- commons-lang.jar

- cxf-xjc*.jar (optional, these are xjcextensions for providing enhanced

       JAXB code generation)

For JAX-WS support:

- geronimo-ws-metadata.jar [6]

- geronimo-jaxws_2.2_spec-1.0.jar (Or theSun equivalent) [6]

- saaj-api.jar [6]

- saaj-impl.jar [6]

- asm.jar (semi-optional, helps withperformance of wrapper types and is

       required when adding JAXB annotations onto the SEI methods and

         parameters.)

For XML Configuration support:

- aopalliance.jar

- spring-beans.jar

- spring-context.jar

- spring-core.jar

- spring.web.jar

- FastInfoset.jar

For standalone HTTP support:

- geronimo-servlet.jar

- jetty-*.jar

- sl4j.jar & sl4j-jdk14.jar (optional -but improves logging)

For Aegis support:

- jdom.jar (optional, if you want to mapxsd:anyType to JDOM)

For XmlBeans databinding support:

- xmlbeans.jar

For WS-Security support:

- bcprov-jdk15.jar

- xalan.jar

- serializer.jar

- wss4j.jar

- xmlsec.jar

- ehcache-core.jar

For SAML support in WS-Security

- joda-time.jar

- opensaml.jar

- openws.jar

- xmltooling.jar

For HTTP Binding support:

- jra.jar

- jettison.jar (Needed for JSON servicesonly)

For JAX-RS support:

- abdera* (optional: for AtomPub support, but also needed for the

           Management log browser console)

- commons-codec.jar (Needed for Abdera)

- jaxen.jar (Needed for Abdera)

- axiom* (Needed for Abdera)

- jsr311-api.jar

- jettison.jar (Needed for JSON servicesonly)

- oauth*.jar (Needed for OAuth support)

For JMS transport

- geronimo-jms.jar (Or the Sun equivalent)

- spring-jms.jar

- spring-tx.jar

For CORBA support:

- antlr.jar

For JavaScript functionality:

- js.jar

For schema validation with the Aegis databinding.

 -msv-core.jar (version 2010.1)

 -xsdlib:jar (version 2010.1)

 -isorelax.jar (version 20030108)

 -relaxngDatatype.jar (version 20020414)

For the WS-Notification Service:

 -cxf-services-wsn-api.jar

 -cxf-services-wsn-core.jar 

For the CXF Security Token Service:

人家官方文件，寫得那麼好，我就不再嚼舌頭了，大家去官網看吧。

瞭解了java Webservice這塊的規範和實現，相信你再次在java中使用Webservice就不會那麼糊塗了，該怎麼做，出了問題怎麼辦，心中有數了吧。