72 lines
4.0 KiB
XML
72 lines
4.0 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!-- ============================================================================= -->
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<!-- Copyright © 2009 Red Hat, Inc. and others. -->
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<!-- -->
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<!-- The text of and illustrations in this document are licensed by Red Hat under -->
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<!-- a Creative Commons Attribution–Share Alike 3.0 Unported license ("CC-BY-SA"). -->
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<!-- -->
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<!-- An explanation of CC-BY-SA is available at -->
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<!-- -->
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<!-- http://creativecommons.org/licenses/by-sa/3.0/. -->
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<!-- -->
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<!-- In accordance with CC-BY-SA, if you distribute this document or an adaptation -->
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<!-- of it, you must provide the URL for the original version. -->
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<!-- -->
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<!-- Red Hat, as the licensor of this document, waives the right to enforce, -->
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<!-- and agrees not to assert, Section 4d of CC-BY-SA to the fullest extent -->
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<!-- permitted by applicable law. -->
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<!-- ============================================================================= -->
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<chapter id="intercepting-operations">
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<title>拦截操作</title>
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<para>ActiveMQ支持<emphasis>拦截器</emphasis>。拦截器可以拦截进入服务器的数据包。每进入服务器
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一个数据包，拦截器就被调用一次，允许一些特殊和处理，例如对包的审计、过滤等。拦截器可以对数据包
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进行改动。</para>
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<section>
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<title>实现拦截器</title>
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<para>拦截器必须要实现<literal>Interceptor接口</literal>：</para>
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<programlisting>
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package org.apache.activemq.api.core.interceptor;
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public interface Interceptor
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{
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boolean intercept(Packet packet, RemotingConnection connection)
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throws ActiveMQException;
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}
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</programlisting>
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<para>它的方法的返回值是很重要的：</para>
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<itemizedlist>
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<listitem>
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<para>如果返回<literal>true</literal>，处理正常进行下去。</para>
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</listitem>
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<listitem>
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<para>如果返回<literal>false</literal>，则处理被中断，其它的拦截器将不会被调用，数据包将不会
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被服务器所处理。</para>
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</listitem>
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</itemizedlist>
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</section>
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<section>
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<title>配置拦截器</title>
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<para>拦截器的配置在<literal>activemq-configuration.xml</literal>文件中：</para>
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<programlisting>
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<remoting-interceptors>
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<class-name>org.apache.activemq.jms.example.LoginInterceptor</class-name>
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<class-name>org.apache.activemq.jms.example.AdditionalPropertyInterceptor</class-name>
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</remoting-interceptors>
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</programlisting>
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<para>拦截器的类（以及它们依赖的类）必须要在服务器的classpath中，否则不能被正常初始化及调用。</para>
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</section>
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<section>
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<title>客户端拦截器</title>
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<para>在客户端也可以有拦截器来拦截<emphasis>来自服务器</emphasis>的数据包。<code>ClientSessionFactory</code>
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的<code>addInterceptor()</code>方法可以用来添加拦截器。</para>
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<para>同样拦截器的类（以及它们依赖的类）必须要在客户端的classpath中，否则它们不能被正常初始化及调用。</para>
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</section>
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<section>
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<title>例子</title>
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<para>参见<xref linkend="examples.interceptor" />。这个例子中展示了如何使用拦截器向发往服务器的消息中
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添加属性。</para>
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</section>
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</chapter>
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