我想像这段代码一样详细了解Java7的这个特性publicStringgetPostcode(Personperson){if(person!=null){Addressaddress=person.getAddress();if(address!=null){returnaddress.getPostcode();}}returnnull;}可以做这样的事情publicStringgetPostcode(Personperson){returnperson?.getAddress()?.getPostcode();}但坦率地说，我不太清楚。请解释一下？ 最