dubbo-admin部署在tomcat后浏览器报错，什么原因导致的？

我用的虚拟机安装的ubuntu系统，在ubuntu系统中把dubbo-admin部署到tomcat后，用zookeeper管理，结果访问tomcat首页一片空白，f12控制台有错误信息：
The character encoding of the plain text document was not declared. The localhost:8080 document will render with garbled text in some browser configurations if the document contains characters from outside the US-ASCII range. The character encoding of the file needs to be declared in the transfer protocol or file needs to use a byte order mark as an encoding signature.
未添加dubbo之前tomcat启动、访问无任何问题！！！调了好久，也换了jdk版本，就是没解决，挺着急的！！！