在不知道xml文件结构的情况下解析xml文件内容

I've been working on learning some new tech using java to parse files and for the msot part it's going well. However, I'm at a lost as to how I could parse an xml file to where the structure is not known upon receipt. Lots of examples of how to do so if you know the structure (getElementByTagName seems to be the way to go), but no dynamic options, at least not that I've found.I've been working on learning some new tech usi