&引用;“不兼容类型”;将收集和映射与java流一起使用时出错
我有这门课:&引用;“不兼容类型”;将收集和映射与java流一起使用时出错,java,stream,Java,Stream,我有这门课: public class AirbnbListing { ... private int price ... public int getPrice() { return price; } 我尝试使用java流从AirbnbListing对象的ArrayList中收集整数价格: ArrayList<AirbnbListing> properties = dataParser.getNeighbourhoodProperties(neighbourhood, 0, -1
public class AirbnbListing {
...
private int price
...
public int getPrice() { return price; }
我尝试使用java流从AirbnbListing对象的ArrayList中收集整数价格:
ArrayList<AirbnbListing> properties = dataParser.getNeighbourhoodProperties(neighbourhood, 0, -1, 0, "All");
ArrayList<Integer> prices =
properties.stream()
.map(AirbnbListing::getPrice)
.collect(Collectors.toList());
arraylistproperties=dataParser.getNeighboryProperties(neighbory,0,-1,0,“All”);
ArrayList价格=
properties.stream()
.map(AirbnbListing::getPrice)
.collect(Collectors.toList());
但我得到了“不兼容类型:推断变量R有不兼容的边界”。不确定问题出在哪里。通过像这样传递参数来创建
ArrayList
ArrayList<Integer> prices =
properties.stream()
.map(AirbnbListing::getPrice)
.collect(Collectors.toCollection(ArrayList::new));//<------- this
ArrayList价格=
properties.stream()
.map(AirbnbListing::getPrice)
.collect(收集器.toCollection(ArrayList::new))//将arraylistprices
更改为List prices