在数据传递和远程调用过程中，有时候调用者传递错误的数据和是调用的方法错误。在Web Service中，不可避免地也会出现这些异常信息，那么我们怎样处理这些异常信息呢?本文就向大家介绍下Web Service处理异常信息方法。
1、编写服务器端的异常类，在远处调用中(WebService)异常类继承RemoteException，记得要序列化下，代码如下：
package com.hoo.exception;
import java.rmi.RemoteException;
/**
* function:定制服务器端异常信息
* @author hoojo
* @createDate Dec 17, 2010 00:00:52 AM
* @file RemoteServerException.java
* @package com.hoo.exception
* @project AxisWebService
* @blog http://blog.csdn.net/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
public class RemoteServerException extends RemoteException {
private static final long serialVersionUID = 1L;
private String message;
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public RemoteServerException() {
System.out.println("Remote Servier Exception ");
}
public void showMessage() {
System.out.println(this.message);
}
}
2、编写客户端的异常信息类，和前面远程传递对象一样。因为我们并不知道服务器端的异常信息类代码，但是通过wsdl的xml文件的描述我们可以知道远程异常类的基本信息：方法、方法参数、返回值等信息，下面是客户端的异常信息类代码：
package com.hoo.exception;
import java.rmi.RemoteException;
/**
* function:本地客户端异常信息
* @author hoojo
* @createDate Dec 17, 2010 00:05:30 AM
* @file LocalClientException.java
* @package com.hoo.exception
* @project AxisWebService
* @blog http://blog.csdn.net/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
public class LocalClientException extends RemoteException {
private static final long serialVersionUID = 3;
private String message;
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public LocalClientException() {
System.out.println("Local Client Exception ");
}
public void showMessage() {
System.out.println(this.message);
}
}
内容几乎一样，就是类名称不同。
3、编写触发异常的WebService服务器端代码
package com.hoo.service;
import com.hoo.exception.RemoteServerException;
/**
* function:发出异常信息
* @author hoojo
* @createDate Dec 17, 2010 00:08:07 AM
* @file ThrowException.java
* @package com.hoo.service
* @project AxisWebService
* @blog http://blog.csdn.net/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
public class ThrowException {
public void doException() throws RemoteServerException {
RemoteServerException rse = new RemoteServerException();
rse.setMessage("服务器端出现异常");
throw rse;
}
}
4、定制wsdd文件，发布当前WebService。
xmlns:java="http://xml.apache.org/axis/wsdd/providers/java">
deserializer="org.apache.axis.encoding.ser.BeanDeserializerFactory" encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"/>
5、用定制好的wsdd文件发布我们的WebService，依旧是命令行：
C:\SoftWare\tomcat-5.0.28\tomcat-5.0.28\webapps\AxisWebService\WEB-INF>java -Djava.ext.dirs=lib org.apache.axis.client.AdminClient -lhttp://localhost:8080/AxisWebService/services/AdminService deployException.wsdd
发布完成后，在浏览器中输入：
http://localhost:8080/AxisWebService/servlet/AxisServlet
即可查看刚才发布的服务信息，但是你点击wsdl链接的时候并不能看到xml的内容，那是因为服务器端抛出了异常导致的。这个不是错误是正常的，不过你可以在web.xml中配置异常的信息页面。
6、编写客户端代码，这里的代码和传递对象的WebService也很类似
package com.hoo.client;
import java.rmi.RemoteException;
import javax.xml.namespace.QName;
import javax.xml.rpc.ServiceException;
import org.apache.axis.client.Call;
import org.apache.axis.client.Service;
import org.apache.axis.encoding.ser.BeanDeserializerFactory;
import org.apache.axis.encoding.ser.BeanSerializerFactory;
import com.hoo.exception.LocalClientException;
import com.hoo.exception.RemoteServerException;
public class TryExceptionClient {
/**
* function:捕捉服务器端异常信息的WebService的客户端
* @author hoojo
* @createDate Dec 17, 2010 00:12:56 AM
* @param args
* @throws ServiceException
* @throws RemoteException
*/
public static void main(String[] args) {
String url = "http://localhost:8080/AxisWebService/services/ThrowException";
Service service = new Service();
try {
Call call = (Call) service.createCall();
/**
* 注册异常类信息和序列化类
* ns:CustomException 和 wsdd 配置文件中的typeMapping中的xmlns:myNSD="ns:CustomException"的对应
* Exception 和 wsdd 配置文件中的typeMapping中的qname="myNSD:Exception"的Exception对应
*/
QName qn = new QName("ns:CustomException", "Exception");
/**
* 这里配置的LocalClientException，会将服务器端的RemoteServerException转换成本地的异常信息LocalClientException
*/
call.registerTypeMapping(LocalClientException.class, qn,
new BeanSerializerFactory(LocalClientException.class,qn),
new BeanDeserializerFactory(LocalClientException.class, qn));
call.setOperationName(new QName(url, "doException"));
call.setTargetEndpointAddress(url);
call.invoke(new Object[]{});
} catch (RemoteServerException e) {
e.showMessage();
System.out.println("RemoteServerException:" e.getMessage());
e.printStackTrace();
} catch (LocalClientException e) {
e.showMessage();
System.out.println("LocalClientException:" e.getMessage());
e.printStackTrace();
} catch (RemoteException e) {
System.out.println("RemoteException:" e.getMessage());
e.printStackTrace();
} catch (ServiceException e) {
System.out.println("ServiceException:" e.getMessage());
e.printStackTrace();
}
}
}
看上面的registerTypeMapping和wsdd文件中的typeMapping有些相同之处吧，下面运行下上面的代码，结果如下：
Local Client Exception
服务器端出现异常
LocalClientException:服务器端出现异常
com.hoo.exception.LocalClientException: 服务器端出现异常
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at org.apache.axis.encoding.ser.BeanDeserializer.(BeanDeserializer.java:104)
at org.apache.axis.encoding.ser.BeanDeserializerFactory.getGeneralPurpose(BeanDeserializerFactory.java:89)
at org.apache.axis.encoding.ser.BaseDeserializerFactory.getDeserializerAs(BaseDeserializerFactory.java:89)
at org.apache.axis.encoding.DeserializationContext.getDeserializer(DeserializationContext.java:464)
at org.apache.axis.encoding.DeserializationContext.getDeserializerForType(DeserializationContext.java:547)
at org.apache.axis.message.SOAPFaultDetailsBuilder.onStartChild(SOAPFaultDetailsBuilder.java:157)
at org.apache.axis.encoding.DeserializationContext.startElement(DeserializationContext.java:1035)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.startElement(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)
at javax.xml.parsers.SAXParser.parse(Unknown Source)
at org.apache.axis.encoding.DeserializationContext.parse(DeserializationContext.java:227)
at org.apache.axis.SOAPPart.getAsSOAPEnvelope(SOAPPart.java:696)
at org.apache.axis.Message.getSOAPEnvelope(Message.java:435)
at org.apache.axis.handlers.soap.MustUnderstandChecker.invoke(MustUnderstandChecker.java:62)
at org.apache.axis.client.AxisClient.invoke(AxisClient.java:206)
at org.apache.axis.client.Call.invokeEngine(Call.java:2784)
at org.apache.axis.client.Call.invoke(Call.java:2767)
at org.apache.axis.client.Call.invoke(Call.java:2443)
at org.apache.axis.client.Call.invoke(Call.java:2366)
at org.apache.axis.client.Call.invoke(Call.java:1812)
at com.hoo.client.TryExceptionClient.main(TryExceptionClient.java:44)
服务器端控制台会输出：Remote Servier Exception
这是在创建异常的时候，在构造函数中输出的。
相信小伙伴们在看完本文后，能够掌握这些Web Service处理异常信息方法，能够更好地处理在使用Web Service时的一些日常异常问题，得到更好的编程体验。
,
