新一代Web Service 实现包 -- AXIS2 学习笔记 （一）

我比较懒惰，不想把user guide全部翻译，就记录一些点吧。

Axis2是全新设计的，在2004年的“Axis峰会”上，大家决定采用新的架构来让Axis更加的富有弹性，更有效率，并且更加的可配置。Axis2现在具有的一些feature:
Speed
Low memory foot print
AXIOM - AXis Object Model
Hot Deployment
Asynchronous Web Services
MEP Support - Message Exchange Patterns
Flexibility
Stability
Component-oriented deployment
Transport framework
WSDL support

有些feature现在看不懂，还是先动手做一下，感性认识一下吧

第一步：下载AXIS2。http://ws.apache.org/axis2/download.cgi。很有趣，在apache的Web Service 的Project目录下面还看不到AXIS2。要下那个binary的版本，因为里面有例程。
第二步：Copy axis2.war到$TOMCAT_HOME/webapps目录下面。Tomcat好像只能用JDK1.4，我在JDK1.5 用不出来。
第三步：打开 http://localhost:8080/axis2，就可以看到axis2的Welcome页面了。点一下Validate 和Services，看是不是都没有错误。都没有错误的话，就表示deploy成功了。那个adminstration页面可以通过上传文件来hot deploy Web service，可以用来remote deploy。
第四步：研究例程。先从"samples/userguide/src"目录下的例程看起。看到写一个web service很简单嘛:

public class MyService {
public OMElement echo(OMElement element) throws XMLStreamException {
//Praparing the OMElement so that it can be attached to another OM Tree.
//First the OMElement should be completely build in case it is not fully built and still
//some of the xml is in the stream.
element.build();
//Secondly the OMElement should be detached from the current OMTree so that it can be attached
//some other OM Tree. Once detached the OmTree will remove its connections to this OMElement.
element.detach();
return element;
}

public void ping(OMElement element) throws XMLStreamException {
//Do some processing
}
public void pingF(OMElement element) throws AxisFault{
throw new AxisFault("Fault being thrown");
}
}

看得出来，函数统一使用OMElement作为参数。在META-INF目录下面有个services.xml文件：
<service name="MyService">
<description>
This is a sample Web Service with two operations,echo and ping.
</description>
<parameter name="ServiceClass" locked="false">userguide.example1.MyService</parameter>
<operation name="echo">
<messageReceiver class="org.apache.axis2.receivers.RawXMLINOutMessageReceiver"/>
</operation>
<operation name="ping">
<messageReceiver class="org.apache.axis2.receivers.RawXMLINOnlyMessageReceiver"/>
</operation>
</service>
呵呵，也很简单嘛。有返回值的就用RawXMLINOutMessageReceiver，没返回值的就用RawXMLINOnlyMessageReceiver。把它们编译(要把axis2的jar写到classpath里去)打包压到 MyService.aar，包里文件目录如下：
./\META-INF/services.xml
./userguide/example1/MyService.class
把MyService.aar拷贝到$TOMCAT_HOME/webapps/axis2/WEB-INF/services，然后去点一下http: //localhost:8080/axis2页面上的Services，也就是http://localhost: 8080/axis2/listServices.jsp，就可以看到MyService已经被列出来了。