Java 8 - 如何将多个字段合并为一个dto? [英] Java 8 - how sum many fields into a dto?
本文介绍了Java 8 - 如何将多个字段合并为一个dto?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
假设我有一个类似的项目:
Let's say I have a class Item like this:
class Item {
private long id;
private BigDecimal value1;
private BigDecimal value2;
private BigDecimal value3;
}
然后我有一个包含许多itens的列表,我想知道总和每个值:
Then I have a list with many itens, I want to know the sum of each of the values:
所以,我知道我可以做类似的事情
So, I know I could do something like
BigDecimal v1 = list.stream().map(Item::value1).reduce(BigDecimal.ZERO, BigDecimal::add);
但是,这样我需要为每个值做同样的事情,我想知道如果有某种方法可以将每个属性总结为只有一个Dto:
However, this way I would need to do the same for each value, I'd like to know if there's some way of summing each attribute into only one Dto like:
class TotalItem {
private BigDecimal value1;
private BigDecimal value2;
private BigDecimal value3;
}
TotalItem t = list.stream().map(???).reduce(BigDecimal.ZERO, BigDecimal::add);
这可能吗?
谢谢提前。
推荐答案
我没有测试它,但我认为你可以在项目上实现添加功能
喜欢:
I didn't test it but I think that you can implement add function on Item
like:
public Item add(Item other) {
Item newItem = new Item(this.value1 + other.value1,
this.value2 + other.value2,
this.value3 + other.value3);
return newItem;
}
然后执行:
Item t = list.stream().reduce(BigDecimal.ZERO, Item::add);
这篇关于Java 8 - 如何将多个字段合并为一个dto?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文