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;
        }
    }

10-08 06:21
查看更多