The Xpath's javadoc could be got from the Dom4j's javadoc.
There are some simple regulation you must follow:
1.When you want to use specific single node:
/AAA
/AAA/CCC
2.When you want to use all the nodes which have the same name:
//BBB
//DDD/CCC
3. * represent all the nodes in the specific path:
/AAA/*
//* ---------> all the nodes
4.The expression which has the square brackets could further specify the node. The number in the bracket gives the position you select/
/AAA[1]
//BBB/CCC[last()]
5.The attribute will be got by the @
//@id
/AAA[@id]
But after knowing the regulation , where should we put it?
//Get the document object
SAXReader reader = new SAXReader();
Document document = reader.read("");
//get the data of node via document's selecNodes() or selectSingleNode()
List<Node> nodes = document.selectNodes(" you can set your regulation here!!");
Node node = document.selectSingleNode(" you can set your regulation here!!");