dubbo 常见错误

目录

• 1. Caused by: java.lang.reflect.MalformedParameterizedTypeException
• 2. Caused by: java.lang.IllegalStateException: Context namespace element 'annotation-config' and its parser class [org.springframework.context.annotation.AnnotationConfigBeanDefinitionParser] are only available on JDK 1.5 and higher
• 3. Caused by: org.xml.sax.SAXParseException; lineNumber: 9; columnNumber: 46; cvc-complex-type.2.4.c: 通配符的匹配很全面, 但无法找到元素 'dubbo:application' 的声明。
• 4. Unsupported major.minor version 52.0 (unable to load class

1. Caused by: java.lang.reflect.MalformedParameterizedTypeException

启动时报错，原因是dubbo 依赖 spring 2.5.6.SEC03，而我项目中有用spring 3.2.4.RELEASE，所以导致冲突。 在maven中把dubbo中的spring依赖去除就可以了。

如果你们项目中也报这个错，很可能也是因为jar包冲突造成的

<dependency>
 <groupId>com.alibaba</groupId>
 <artifactId>dubbo</artifactId>
 <exclusions> 
     <exclusion> 
         <artifactId>spring</artifactId> 
         <groupId>org.springframework</groupId> 
     </exclusion> 
 </exclusions> 
</dependency>

2. Caused by: java.lang.IllegalStateException: Context namespace element 'annotation-config' and its parser class [org.springframework.context.annotation.AnnotationConfigBeanDefinitionParser] are only available on JDK 1.5 and higher

at org.springframework.context.config.ContextNamespaceHandler$1.parse(ContextNamespaceHandler.java:65)
at org.springframework.beans.factory.xml.NamespaceHandlerSupport.parse(NamespaceHandlerSupport.java:69)
at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseCustomElement(BeanDefinitionParserDelegate.java:1297)
at org.springframework.beans.factory.xml.BeanDefinitionParserDelegate.parseCustomElement(BeanDefinitionParserDelegate.java:1287)
at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.parseBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:135)
at org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.registerBeanDefinitions(DefaultBeanDefinitionDocumentReader.java:92)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.registerBeanDefinitions(XmlBeanDefinitionReader.java:507)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:398)
... 22 more

错误原因：http://stackoverflow.com/questions/23813369/spring-java-error-namespace-element-annotation-config-on-jdk-1-5-and-high

因为使用了 jdk1.8, 而dubbo 依赖 Spring 2.5 ，而Spring2.5仅仅支持 jdk1.5 到 jdk 1.7, 所以jdk 1.8 不被识别，所以报错。

3. Caused by: org.xml.sax.SAXParseException; lineNumber: 9; columnNumber: 46; cvc-complex-type.2.4.c: 通配符的匹配很全面, 但无法找到元素 'dubbo:application' 的声明。

该错误是因为没有引入 dubbo jar包。加上依赖就行了：

   <!-- dubbo相关 -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>dubbo</artifactId>
      <!-- 排除依赖 -->
      <exclusions>
        <exclusion>
          <groupId>org.springframework</groupId>
          <artifactId>spring</artifactId>
        </exclusion>
        <exclusion>
          <groupId>org.jboss.netty</groupId>
          <artifactId>netty</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
    <dependency>
      <groupId>org.apache.zookeeper</groupId>
      <artifactId>zookeeper</artifactId>
    </dependency>
    <dependency>
      <groupId>com.github.sgroschupf</groupId>
      <artifactId>zkclient</artifactId>
    </dependency>

4. Unsupported major.minor version 52.0 (unable to load class

出现该错误是由于class编译器的JDK版本高于运行期的JDK版本。

比如我在运行Tomcat servlet时出现该错误，是由于tomcat运行时是1.7的JDK，Eclipse编译时则是1.8

修改方法：保证编译器和运行期的JDK版本一致。