泛型无法转换错误java List
即使泛型无法转换错误java List,java,generics,Java,Generics,即使List是列表如果您使用的是java 7+,您只需执行new HashMap() List<? extends Number> ls = new ArrayList<Number>(); //(1) Map <String,List<? extends Number>> mp = new HashMap<String,List<Number>>(); //(2) Map <String,List<? exte
List
是列表如果您使用的是java 7+,您只需执行new HashMap()代码>
List<? extends Number> ls = new ArrayList<Number>(); //(1)
Map <String,List<? extends Number>> mp = new HashMap<String,List<Number>>(); //(2)
Map <String,List<? extends Number>> mp = new HashMap<String,List<? extends Number>>(); //(3)
Map <String,List<? extends Number>> mp = new HashMap<String,List<Number>>();
Map <String, ? extends List<? extends Number>> mp = new HashMap<String,List<Number>>();