list转map

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

 

List<Apple> appleList = new ArrayList<>();//存放apple对象集合
Apple apple1 =  new Apple(1,"苹果1",new BigDecimal("3.25"),10);
Apple apple12 = new Apple(1,"苹果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
连接：https://www.jianshu.com/p/ae14101989f2
來源：简书
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