1. 解释“arraylist cannot be cast to map”错误的含义 这个错误表明你尝试将一个ArrayList对象强制转换(cast)为Map对象,但在Java中,ArrayList和Map是两种完全不同的数据结构,它们之间没有继承关系,因此这种转换是不合法的。这会导致运行时异常ClassCastException。 2. 指出ArrayList和Map数据结构之间的根本区别 ArrayL...
forEach((key, value) -> map.put(key, value)); 在上面的代码中,我们首先创建了一个ArrayList对象,并向其中添加了一些键值对。然后,我们创建了一个HashMap对象,并使用Collections.asMap方法将ArrayList转换为Map。最后,我们使用forEach方法将ArrayList中的键值对添加到Map中。请注意,此方法要求键和值具有相同的顺...
Map<String,Object> map=(Map<String, Object>) itemList.get(j).get(i); } }
If you already have one, you are all set. I am getting a java.util.ArrayList cannot be cast to java.util.Map error when trying to convert to the X12 EDI adapter. I know why, just not sure how to fix this. Below is the dataweave. I have to loop through all the items and create...
java.lang.ClassCastException: java.util.ArrayList cannot be cast to java.util.Map at service.impl.BillServiceImpl.exportBillExcel(BillServiceImpl.java:336) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ...
1、错误描述 java.lang.ClassCastException: java.util.ArrayList cannot be cast to java.util.Map at service.impl.BillServiceImpl.exportBillExcel(BillServiceImpl.java:336) at sun.reflect.NativeMethodAccessor ...
)返回 { "code" : 1,"message" : "java.util.ArrayList cannot be cast to java.util.Map"} ...
it.next()，这里遍历的是List里面的对象，如果没看日志的话，你是list里面放了多个list,那你转化的时候就要转化为你存入List的对象--List
Query:select * from sometable where (d = 153 limit 1 SQLActionException: INTERNAL_SERVER_ERROR 5000 ClassCastException: java.util.ArrayList cannot be cast to java.util.Map at io.crate.types.ObjectType.value(ObjectType.java:59) at io.crate.types.ObjectType.value(ObjectType.java:32) at io...
Exception in thread"main"java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.util.ArrayListat collection.ConvertArray.main(ConvertArray.java:22)。 ~~~ 结语:我只想把我所知道的,尽量简洁清楚地表达出来。