<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Apache Dubbo – 广播</title><link>https://chickenlj.github.io/incubator-dubbo-website/cn/java-sdk/reference-manual/registry/multicast/</link><description>Recent content in 广播 on Apache Dubbo</description><generator>Hugo -- gohugo.io</generator><language>en-us</language><atom:link href="https://chickenlj.github.io/incubator-dubbo-website/cn/java-sdk/reference-manual/registry/multicast/index.xml" rel="self" type="application/rss+xml"/><item><title>Java-Sdk: 概述</title><link>https://chickenlj.github.io/incubator-dubbo-website/cn/java-sdk/reference-manual/registry/multicast/overview/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://chickenlj.github.io/incubator-dubbo-website/cn/java-sdk/reference-manual/registry/multicast/overview/</guid><description/></item><item><title>Java-Sdk: 使用说明</title><link>https://chickenlj.github.io/incubator-dubbo-website/cn/java-sdk/reference-manual/registry/multicast/guide/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://chickenlj.github.io/incubator-dubbo-website/cn/java-sdk/reference-manual/registry/multicast/guide/</guid><description>
&lt;p>Multicast 注册中心不需要启动任何中心节点，只要广播地址一样，就可以互相发现。&lt;/p>
&lt;p>&lt;img src="https://chickenlj.github.io/incubator-dubbo-website/imgs/user/multicast.jpg" alt="/user-guide/images/multicast.jpg">&lt;/p>
&lt;ol start="0">
&lt;li>提供方启动时广播自己的地址&lt;/li>
&lt;li>消费方启动时广播订阅请求&lt;/li>
&lt;li>提供方收到订阅请求时，单播自己的地址给订阅者，如果设置了 &lt;code>unicast=false&lt;/code>，则广播给订阅者&lt;/li>
&lt;li>消费方收到提供方地址时，连接该地址进行 RPC 调用。&lt;/li>
&lt;/ol>
&lt;p>组播受网络结构限制，只适合小规模应用或开发阶段使用。组播地址段: 224.0.0.0 - 239.255.255.255&lt;/p>
&lt;h2 id="配置">配置&lt;/h2>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-xml" data-lang="xml">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;dubbo:registry&lt;/span> address=&lt;span style="color:#2aa198">&amp;#34;multicast://224.5.6.7:1234&amp;#34;&lt;/span> &lt;span style="color:#268bd2">/&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>或&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-xml" data-lang="xml">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;dubbo:registry&lt;/span> protocol=&lt;span style="color:#2aa198">&amp;#34;multicast&amp;#34;&lt;/span> address=&lt;span style="color:#2aa198">&amp;#34;224.5.6.7:1234&amp;#34;&lt;/span> &lt;span style="color:#268bd2">/&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>为了减少广播量，Dubbo 缺省使用单播发送提供者地址信息给消费者，如果一个机器上同时启了多个消费者进程，消费者需声明 &lt;code>unicast=false&lt;/code>，否则只会有一个消费者能收到消息; 当服务者和消费者运行在同一台机器上，消费者同样需要声明&lt;code>unicast=false&lt;/code>，否则消费者无法收到消息，导致No provider available for the service异常：&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-xml" data-lang="xml">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;dubbo:application&lt;/span> name=&lt;span style="color:#2aa198">&amp;#34;demo-consumer&amp;#34;&lt;/span>&lt;span style="color:#268bd2">&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dubbo:parameter&lt;/span> key=&lt;span style="color:#2aa198">&amp;#34;unicast&amp;#34;&lt;/span> value=&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span> &lt;span style="color:#268bd2">/&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;/dubbo:application&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>或&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-xml" data-lang="xml">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;dubbo:consumer&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dubbo:parameter&lt;/span> key=&lt;span style="color:#2aa198">&amp;#34;unicast&amp;#34;&lt;/span> value=&lt;span style="color:#2aa198">&amp;#34;false&amp;#34;&lt;/span> &lt;span style="color:#268bd2">/&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;/dubbo:consumer&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div></description></item></channel></rss>