CXF之Interceptors

 

1.  Interceptors and Phases(拦截器与阶段)

Interceptors是CXF内部的根本处理单元。当服务被调用时，一个InterceptorChain被创建并调用。

每一个interceptor都有机会做他们想要处理的消息。包括：读取，转化，处理头部，验证消息 ，等。

 

Interceptors可以用于CXF的客户端和服务端。当一个CXF客户端调用一个CXF服务端的时候，

客户端有一个传出的interceptor链，服务端有一个传入的interceptor链。当服务端发送响应给

客户端时，服务端有一个传出的interceptor链，客户端有一个传入的interceptor链。此外，在

SOAPFaults情况下，一个CXF web服务将创建单独的对外输出错误处理链，客户端将创建一个

传入的错误处理链。

 

InterceptorChains被划分成阶段。每个阶段可以包含许多interceptors. 在传入链中，你将有以下几个阶段：

Phase---------------------------------------------Functions

-----------------------------------------------------------------------------------------------------------------

RECEIVE------------------------------------------Transport level processing

(PRE/USER/POST)_STREAM--------------------Stream level processing/transformations

READ----------------------------------------------This is where header reading typically occurs.

(PRE/USER/POST)_PROTOCOL----------------Protocol processing, such as JAX-WS SOAP handlers

UNMARSHAL--------------------------------------Unmarshalling of the request

(PRE/USER/POST)_LOGICAL-------------------Processing of the umarshalled request

PRE_INVOKE--------------------------------------Pre invocation actions

INVOKE--------------------------------------------Invocation of the service

POST_INVOKE------------------------------------Invocation of the outgoing chain if there is one

 

传出链中，也有几个阶段:

Phase Functions

----------------------------------------------------------------------------------------------------------------

SETUP----------------------------------------------Any set up for the following phases

(PRE/USER/POST)_LOGICAL-------------------Processing of objects about to marshalled

PREPARE_SEND----------------------------------Opening of the connection

PRE_STREAM 

PRE_PROTOCOL----------------------------------Misc protocol actions.

WRITE----------------------------------------------Writing of the protocol message, such as the SOAP Envelope.

MARSHAL-------------------------------------------Marshalling of the objects

(USER/POST)_PROTOCOL-----------------------Processing of the protocol message.

(USER/POST)_STREAM---------------------------Processing of the byte level message

SEND------------------------------------------------Final sending of message and closing of transport stream

 

2. InterceptorProviders

CXF包含的几个不同的组件可以提供将interceptors放到InterceptorChain中. 它们实现了InterceptorProvider接口：

public interface InterceptorProvider { List<Interceptor> getInInterceptors(); List<Interceptor> getOutInterceptors(); List<Interceptor> getOutFaultInterceptors(); List<Interceptor> getInFaultInterceptors();} 

添加一个interceptor到一个interceptor链，你只需要把它添加到一个InterceptorProviders：

MyInterceptor interceptor = new MyInterceptor();provider.getInInterceptors().add(interceptor); 

 

CXF包含的一些InterceptorProviders是：

. Client

. Endpoint

. Service

. Bus

. Binding

 

 

 

 

3. 编写并配置一个Interceptor

 

编写一个Interceptor

 

写一个拦截器是相对简单的。你的interceptor需要继承AbstractPhaseInterceptor或者它的许多子类，例如AbstractSoapInterceptor.

从AbstractPhaseInterceptor继承，允许你的interceptor访问消息接口的方法 。如例：

import java.io.IOException;import org.apache.cxf.attachment.AttachmentDeserializer;import org.apache.cxf.message.Message;import org.apache.cxf.phase.AbstractPhaseInterceptor;import org.apache.cxf.phase.Phase;public class AttachmentInInterceptor extends AbstractPhaseInterceptor<Message> { public AttachmentInInterceptor() { super(Phase.RECEIVE); } public void handleMessage(Message message) { String contentType = (String) message.get(Message.CONTENT_TYPE); if (contentType != null && contentType.toLowerCase().indexOf("multipart/related") != -1) { AttachmentDeserializer ad = new AttachmentDeserializer(message); try { ad.initializeAttachments(); } catch (IOException e) { throw new Fault(e); } } } public void handleFault(Message messageParam) { }} 

 

 

继承自AbstractPhaseInterceptor的子类，允许你的interceptor访问比在Message接口中更多的信息。

AbstractSoapInterceptor是AbstractPhaseInterceptor的子类。继承自这个类，允许你的interceptor

访问SoapMessage类的SOAP头和版本消息。如例：

import java.util.Collection;import java.util.List;import java.util.Map;import org.apache.cxf.binding.soap.Soap11;import org.apache.cxf.binding.soap.Soap12;import org.apache.cxf.binding.soap.SoapMessage;import org.apache.cxf.binding.soap.model.SoapOperationInfo;import org.apache.cxf.endpoint.Endpoint;import org.apache.cxf.helpers.CastUtils;import org.apache.cxf.interceptor.Fault;import org.apache.cxf.message.Exchange;import org.apache.cxf.message.Message;import org.apache.cxf.phase.Phase;import org.apache.cxf.service.model.BindingOperationInfo;import org.apache.cxf.service.model.OperationInfo;public class SoapActionInInterceptor extends AbstractSoapInterceptor { public SoapActionInInterceptor() { super(Phase.READ); addAfter(ReadHeadersInterceptor.class.getName()); addAfter(EndpointSelectionInterceptor.class.getName()); } public void handleMessage(SoapMessage message) throws Fault { if (message.getVersion() instanceof Soap11) { Map<String, List<String>> headers = CastUtils.cast((Map)message.get(Message.PROTOCOL_HEADERS)); if (headers != null) { List<String> sa = headers.get("SOAPAction"); if (sa != null && sa.size() > 0) { String action = sa.get(0); if (action.startsWith("/"")) { action = action.substring(1, action.length() - 1); } getAndSetOperation(message, action); } } } else if (message.getVersion() instanceof Soap12) { ........... } } private void getAndSetOperation(SoapMessage message, String action) { if ("".equals(action)) { return; } Exchange ex = message.getExchange(); Endpoint ep = ex.get(Endpoint.class); BindingOperationInfo bindingOp = null; Collection<BindingOperationInfo> bops = ep.getBinding().getBindingInfo().getOperations(); for (BindingOperationInfo boi : bops) { SoapOperationInfo soi = (SoapOperationInfo) boi.getExtensor(SoapOperationInfo.class); if (soi != null && soi.getAction().equals(action)) { if (bindingOp != null) { //more than one op with the same action, will need to parse normally return; } bindingOp = boi; } } if (bindingOp != null) { ex.put(BindingOperationInfo.class, bindingOp); ex.put(OperationInfo.class, bindingOp.getOperationInfo()); } }} 

注意，你需要指定这阶段要包含进来的interceptor. 这是在拦截器的构造器上进行：

public class MyInterceptor extends AbstractSoapInterceptor{public MyInterceptor(){super(Phase.USER_PROTOCOL);}...} 

你还可以在拦截器运行前/后在同一阶段定义某些其它拦截器:

public class MyInterceptor extends AbstractSoapInterceptor { public MyInterceptor() { super(Phase.USER_PROTOCOL); // MyInterceptor needs to run after SomeOtherInterceptor getAfter().add(SomeOtherInterceptor.class.getName()); // MyInterceptor needs to run before YetAnotherInterceptor getBefore().add(YetAnotherInterceptor.class.getName()); } ...} 

你可以添加interceptors到interceptor链中，通过编程方式 或 配置方式. ----略。