【JAVA】java中将一个list进行拆解重新组装

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于 2025-01-03 10:53:28 发布

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分类专栏： java 文章标签： java list windows

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一、使用场景

1、当需要对一个list中的元素属性进行重新赋值，比如一个list中存储了订单数据，我们需要改变list中每个订单的id，然后再重新输出订单list

if(CollectionUtils.isNotEmpty(orderList)){
orderList.forEach(p->{
PointsExchangeOrderItem item = new PointsExchangeOrderItem();
item.setOrderId(p.getId());
List<PointsExchangeOrderItem> itemList = item.select();
if (CollectionUtils.isNotEmpty(itemList)){
List<String> collects = itemList.stream().map(PointsExchangeOrderItem::getExchangeId).collect(Collectors.toList());
String exchangeIdStr = String.join(",", collects);
p.setExchangeInPointsId(exchangeIdStr);
p.setExchangeOutPointsId(exchangeIdStr);

}

});
}

return orderList;

      if(CollectionUtils.isNotEmpty(orderList)){
            orderList.forEach(p->{
                PointsExchangeOrderItem item = new PointsExchangeOrderItem();
                item.setOrderId(p.getId());
                List<PointsExchangeOrderItem> itemList = item.select();
                if (CollectionUtils.isNotEmpty(itemList)){
                    List<String> collects = itemList.stream().map(PointsExchangeOrderItem::getExchangeId).collect(Collectors.toList());
                    String exchangeIdStr = String.join(",", collects);
                    p.setExchangeInPointsId(exchangeIdStr);
                    p.setExchangeOutPointsId(exchangeIdStr);

                }


            });
        }

        return orderList;