java 实例化泛型且赋值
实例化泛型
Class <T> clazz = (Class <T>) ((ParameterizedType) new Entity().getClass().getGenericSuperclass()).getActualTypeArguments()[0]; T dto = clazz.newInstance();
泛型方法
/** * * @param clazz * @param book * @param sheetIndex * @param <T> * @return * @throws IllegalAccessException * @throws InstantiationException */ public static <T> List<T> toEntity(Class<T> clazz,Workbook book, int sheetIndex) throws IllegalAccessException, InstantiationException { List<T> list = new ArrayList<>(); // Class <T> clazz = (Class <T>) ((ParameterizedType) entity.getClass().getGenericSuperclass()).getActualTypeArguments()[0]; T dto = clazz.newInstance(); T dto2 = clazz.newInstance(); Field[] fields = clazz.getDeclaredFields(); Map<String, Field> fieldMap = new LinkedHashMap<>(); for (Field field : fields) { String mod = Modifier.toString(field.getModifiers()); System.out.println("mod = " + mod); // 跳过静态属性 if (mod.indexOf("static") != -1) { continue; } // 取得注解的设置的属性值 Description setField = field.getAnnotation(Description.class); if (setField != null) { String fieldName = setField.key(); String fieldType = setField.value(); // 必须,不然赋值会出现异常 field.setAccessible(true); fieldMap.put(fieldType, field); System.out.println("注解的属性 fieldName = " + fieldName); System.out.println("注解的属性 fieldType = " + fieldType); } } int num = 0; for (String key : fieldMap.keySet()) { num++; fieldMap.get(key).set(dto, "dto1:" + key + num); fieldMap.get(key).set(dto2, "dto2:" + key + num); } list.add(dto); return list; }