/**
* Resolve the given path, replacing placeholders with
corresponding
* system property values if necessary. Applied to config
locations.
* @param path the original file path
* @return the resolved
file path
* @see
org.springframework.util.SystemPropertyUtils#resolvePlaceholders
*/
用系统定义的值，比如: 类路径替换 "java.class.path"
resolvePath(String path)