list轉map

public class Apple {
    private Integer id;
    private String name;
    private BigDecimal money;
    private Integer num;
   /*構造函數*/
}

 

List<Apple> appleList = new ArrayList<>();//存放apple對象集合
Apple apple1 =  new Apple(1,"蘋果1",new BigDecimal("3.25"),10);
Apple apple12 = new Apple(1,"蘋果2",new BigDecimal("1.35"),20);
Apple apple2 =  new Apple(2,"香蕉",new BigDecimal("2.89"),30);
Apple apple3 =  new Apple(3,"荔枝",new BigDecimal("9.99"),40);
appleList.add(apple1);
appleList.add(apple12);
appleList.add(apple2);
appleList.add(apple3);

 

Map<Integer, Apple> appleMap = appleList.stream().collect(Collectors.toMap(Apple::getId, a -> a,(k1,k2)->k1));

做者：Tommmmm
連接：https://www.jianshu.com/p/ae14101989f2
來源：簡書
簡書著做權歸做者全部，任何形式的轉載都請聯繫做者得到受權並註明出處。