BeanUtils.copyProperties 大家都知道是用來作為屬性複製的工具，最近在專案遇到了一個坑

class A{
    private String name;
    private List<Cat> cats;
    private String age;
}
class Cat{
    private String color;
    private String price;
    private String count;

}


class A1{
    private String name;
    private List<Cat> cats;
}
class Cat1{
    private String color;
    private String price;

}

//開始複製
A a=new A();
a.setName("cd");
a.setAge("11");
Cat cat=new Cat();
cat.setColor("red");
cat.setPrice("200");
cat.setCount("20");
a.setCat(cat);

A1 a1=new A1();
BeanUtils.copyProperties(a1,a);
//我們想得到的a1為
a1:{"name":"cd","cat":{"price":"200","color":"red"}}
//實際的結果為
a1:{"name":"cd","cat":{"price":"200","color":"red","count":"20"}}
//所以大家進行屬性複製的時候注意List，當有List的時候我們要取出來一個一個複製