泛型作用：
泛型：集合類添加對象不用強轉(zhuǎn)
反射機制：將泛型固定的類的所有方法和成員全部顯示出來
核心代碼：
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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);//這里不再需要強轉(zhuǎn) |
代碼實例：
說明：這是非泛型的代碼，集合類中調(diào)用對象時需要強轉(zhuǎn)
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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);//這樣顯然是不對的 }}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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原文鏈接：https://www.cnblogs.com/cate/java/
