dubbo中關於protocol的配置
protocol 一個項目中可以配置多個，如果未定義port默認爲20880（本人因爲從網上copy了一個
<dubbo:protocol accesslog="true"/>，而且已定義<dubbo:protocol name="dubbo" port="20880" />,當我啓動項目的多個實例時只修改了定義端口的protocol，而默認的未被修改，其他dubbo服務就會報端口已被佔用程序退出的異常）
錯誤代碼片段：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">
<dubbo:application name="demo-provider" />
<dubbo:registry address="zookeeper://localhost:2181"/>
<!-- 用dubbo協議在20880端口暴露服務 -->
<dubbo:protocol name="dubbo" port="20880" />
<dubbo:protocol accesslog="true" />
<dubbo:service interface="com.ssyt.dubbo.demo.DemoService" ref="demoService"/>
<bean id="demoService" class="com.ssyt.dubbo.dome.provider.DemoServiceImpl"/>
</beans>
紅色部分爲衝突代碼，可改爲不同的端口，一個項目中一種協議最好只定義一次
修改後的代碼爲：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">
<dubbo:application name="demo-provider" />
<dubbo:registry address="zookeeper://localhost:2181"/>
<!-- 用dubbo協議在20880端口暴露服務 -->
<dubbo:protocol name="dubbo" port="20880" accesslog="true"/>
<dubbo:service interface="com.ssyt.dubbo.demo.DemoService" ref="demoService"/>
<bean id="demoService" class="com.ssyt.dubbo.dome.provider.DemoServiceImpl"/>
</beans>