泛型超类和超类类之间的区别 [英] Difference between generic super class and super class type

问题描述

我无法理解下面两个代码片段之间的区别。有人可以帮我解释一下吗？

首先，我必须说我有很多类来扩展名为 BaseEntity ，那么以下代码片段的区别，优点和缺点是什么？

  // 1 
 public< T扩展BaseEntity> T getName（T t）{
 return t; 
} 
 
 // 2 
 public BaseEntity getName（BaseEntity t）{
 return t; 
 
  

解决方案

第一个片段更加灵活因为它保留了 T 的实际类型。假设您有一个子类：

  class SubEntity extends BaseEntity {} 
   
 
 $ b 
在第一种情况下，您可以编写： 
 
 
  SubEntity结果= getName（new SubEntity（））; 
  
但在第二种情况下，您需要投射： 
 
 
  SubEntity result =（SubEntity）getName（new SubEntity（））; 
  
 
I can't understand the difference between the two code snippets below. Can someone help me with a simple explanation?


First of all, I have to say that I have a lot of classes that extend a super class named BaseEntity, so what are the differences, benefits and drawbacks of the following snippets?
// 1
public <T extends BaseEntity> T getName(T t) {
    return t;
}

// 2
public BaseEntity getName(BaseEntity t) {
    return t;
}

解决方案
The first snippet is more flexible as it preserves the actual type of T. Suppose you have a subclass:
class SubEntity extends BaseEntity {}
In the first case you can write:
SubEntity result = getName(new SubEntity());
But in the second case you will need a cast:
SubEntity result = (SubEntity)getName(new SubEntity());


                        
这篇关于泛型超类和超类类之间的区别的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！