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;