提供了List转为Map的2种方法,第一种convertOne是常规转换,以key作为map的key,以list中的E作为value;第二种则以key作为map的key,以list作为value @SuppressWarnings("unchecked")final public class MapConverter {    private static final String GET = "get";    private MapConverter() {        throw new AssertionError("Util禁止反射实例化");    }    public static 
     
       Map
      
        convertOne(List
       
         list, String key) {        if (CollectionUtils.isEmpty(list)) {            return null;        }        Map
        
          map = null;        try {            Method getM = getMethod(list.get(0).getClass(), key);            map = new HashMap<>();            for (E en : list) {                K k = (K) getM.invoke(en);                map.put(k, en);            }        } catch (Exception e) {            e.printStackTrace();        }        return map;    }    public static 
         
           Map
          
           > convertList(List
           
             list, String key) { if (CollectionUtils.isEmpty(list)) { return null; } Map
            
             > map = null; try { Method getM = getMethod(list.get(0).getClass(), key); map = new HashMap<>(); for (E en : list) { K k = (K) getM.invoke(en); List
             
               res = map.get(k); if (res != null) { res.add(en); } else { List
              
                l1 = new ArrayList<>(); l1.add(en); map.put(k, l1); } } } catch (Exception e) { e.printStackTrace(); } return map; } private static Method getMethod(Class clazz, String key) throws NoSuchMethodException { if (key.startsWith(GET)) { return clazz.getMethod(key); } if (Character.isUpperCase(key.charAt(0))) { clazz.getMethod(GET + key); } return clazz.getMethod(GET + Character.toUpperCase(key.charAt(0)) + key.substring(1)); }}