开始创建xml配置文件时，先把标签打出来，就出现了错误：The content of element type “configuration” must match
(properties?,settings?,typeAliases?,typeHandlers?,objectFactory?,objectWrapperFactory?,reflectorFactory?,plugins?,environments?,databaseIdProvider?,mappers?)".
即使全部打完也会提示出错
这是因为标签没有按顺序创建，解决方法：顺序创建标签
