Rtu obj=new Rtu();
List<Cargo> cargos = obj.getCargos();
cargos.add(new Cargo());
cargos.add(new Cargo());
cargos.add(new Cargo());
obj.setCargos(cargos);
Field[] fields = obj.getClass().getDeclaredFields();//Object是已经被赋值的对象实例
for (Field field : fields) {
if (!field.isAccessible()) {
field.setAccessible(true);
}
if (List.class.isAssignableFrom(field.getType())) {
Method m = List.class.getDeclaredMethod("size");
int size = (Integer) m.invoke(field.get(obj));//调用list的size方法，得到list的长度
System.out.println(size);
}
}
}
