2022-08-19 Java数组转HashMap

public class SelfTest {
    public static void main(String[] args) {
        FoodCategory[] arr = new FoodCategory[] {
                new FoodCategory(1,0,"素食"),
                new FoodCategory(2,1,"蔬菜"),
                new FoodCategory(3,1,"韭菜"),

                new FoodCategory(4,0,"肉食"),
                new FoodCategory(5,4,"香肠"),
                new FoodCategory(6,4,"鸡腿"),
        };
        Map<Integer, FoodCategory> result = Arrays.stream(arr)
                .collect(Collectors.toMap(FoodCategory::getId,  t->t));
        System.out.println(result);
    }
}

{1=素食, 2=蔬菜, 3=韭菜, 4=肉食, 5=香肠, 6=鸡腿}

class FoodCategory {
    private Integer id;
    private Integer parentId;
    private String nickname;

    public FoodCategory(Integer id, Integer parentId, String nickname) {
        this.id = id;
        this.parentId = parentId;
        this.nickname = nickname;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getParentId() {
        return parentId;
    }

    public void setParentId(Integer parentId) {
        this.parentId = parentId;
    }

    public String getNickname() {
        return nickname;
    }

    public void setNickname(String nickname) {
        this.nickname = nickname;
    }

    @Override
    public String toString() {
        return nickname;
    }
}