java - 如何检查List或Set类型的字段是否为空？

Question

我有这样的代码：

for (final Field field : fields) { 
    if (Collection.class.isAssignableFrom(field.getType())) { 

    } 
} 

如何检查是否领域（可以列出或设置类型）为空或空？

Answer 1

您可以使用此：

for (final Field field : fields) 
{ 
    if (Collection.class.isAssignableFrom(field.getType())) 
    { 
     field.setAccessible(true); // required if the field is not public (that is very likely) 
     if (((Collection) field.get(object)).isEmpty()) // "object" being the object which owns your fields 
     { 
      System.out.println("Field is empty"); 
     } 
    } 
}