For instance, Listing 6 shows how a regular expression can be used to extract the date of the firstorder in a customer's order History.
例如，清单6显示了如何用正则表达式从顾客的订单历史中提取第一笔订单的日期。
2
First off, in order to form a legal new expression on a type parameter, such as new T(), it's necessary to make sure that we're calling a constructor that is valid for every instantiation of T.
首先， 为了对类型参数构造合法的 new 表达式（如 new T() ）， 必须确保我们调用的构造函数对于 T 的每个实例化都有效。
3
If the XPath expression does return more than one node and you've specified XPathConstants.NODE, then evaluate returns the first node in document order.