泛型作用:
泛型:集合类添加对象不用强转
反射机制:将泛型固定的类的所有方法和成员全部显示出来
核心代码:
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ArrayList<Ls> ff= new ArrayList()<Ls>; Ls ls1= new Ls( "薯片" ,5f); ff.add(ls1); Ls cls=ff.get( 0 ); //这里不再需要强转 |
代码实例:
说明:这是非泛型的代码,集合类中调用对象时需要强转
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import java.util.*; public class L4_6 { public static void main(String[] args) { //Hashtable ff=new Hashtable(); ArrayList ff= new ArrayList(); Ls ls1= new Ls( "薯片" ,5f); ff.add(ls1); Ls cls=(Ls)ff.get( 0 ); Yl hyl=(Yl)ff.get( 0 ); //这样显然是不对的 } } class Ls { private String mingcheng; private float jiage; Ls(String mingcheng, float jiage) { this .mingcheng=mingcheng; this .jiage=jiage; } } class Yl { private String mingcheng; private float jiage; private String yanse; Yl(String mingcheng, float jiage,String yanse) { this .mingcheng=mingcheng; this .jiage=jiage; this .yanse=yanse; } } |
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原文链接:https://www.cnblogs.com/cate/java/