从svn上拉过来一个使用了dubbo的项目，一套流程走出来，xml中始终有鲜艳的红叉叉，错误原因：
Multiple annotations found at this line:
- schema_reference.4: Failed to read schema document 'http://code.alibabatech.com/schema/dubbo/dubbo.xsd', because 1) could not find the
document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
- cvc-complex-type.2.4.c: The matching wildcard is strict, but no declaration can be found for element 'dubbo:reference'.
http://code.alibabatech.com已经停止服务，所以需要自己改一下配置
从maven库里面找到dubbo.jar，解压得到dubbo.xsd，
window>preferences>xml>xml catalog>add