我有这样的代码:
List<TRt> listTrt;
List<TRtKuesioner> listTrtKuesioner;
List<TArtKuesioner> listTArtKuesioner;
Object[] objects = new Object[] {
listTrt, listTrtKuesioner,listTArtKuesioner
};
我怎样才能像我下面的愿望那样工作:
for(Object o :objects){
if(o instanceof List<TRt>){
}else if(o instanceof List<TRtKuesioner>){
}else if(o instanceof List<TArtKuesioner>){
}
}
我怎样才能做到这一点?
最佳答案
您可以使用isAssignableFrom
进行模拟,以检查第一个元素,然后转换整个List。
例如:
public static void main(String[] args) throws Exception {
List<String> strings = new ArrayList<String>();
strings.add("jora string");
List<Integer> ints = new ArrayList<Integer>();
ints.add(345);
Object[] objs = new Object[]{strings,ints};
for (Object obj : objs){
if (isListInstanceOf(obj, String.class)){
List<String> strs = castListTo(obj, String.class);
for (String str : strs){
System.out.println(str);
}
}else if (isListInstanceOf(obj, Integer.class)){
List<Integer> inList = castListTo(obj, Integer.class);
for (Integer integ : inList){
System.out.println("Int: "+integ);
}
}
}
}
public static boolean isListInstanceOf(Object list, Class clazz){
return (list instanceof List && ((List)list).size() > 0) ? ((List)list).get(0).getClass().isAssignableFrom(clazz) : false;
}
public static <T> List<T> castListTo(Object list, Class<T> clazz){
try{
return (List<T>)list;
}catch(ClassCastException exc){
System.out.println("can't cast to that type list");
return null;
}
}