如何从Java中的对象向量中获取特定的类型对象 [英] How to get a specific type object from an Object Vector in Java

问题描述

我有以下的 Vector ，并且在运行时我要传递一个整数，字符或浮点数：

  public static Vector< Object> interestingValues = new Vector< Object>（）; 
  

同时我想得到整数， Float ，或 Character ，所以有两件事情：

• 它们是否保留了特定的整数 / Float / Character 输入 Object Vector ，或者所有将以 Object ？形式存储。
  

• 如何检索整数从这个 Vector的对象？

$ b

 整数i =（整数）interestingValues.get（ 0）; 
  

如果Vector中有多种类型的对象，可以使用 instanceof ：

  Object o = interestingValues.get（0）; 
 if（o实例的整数）{
整数i =（整数）o; 
} else if（o instanceof Long）{
 Long l =（Long）o; 
 
 
 
 $ b $ p 
 $ b 
你可以做的第三件事是避免需要把对象转换成特定的类型正在使用类型为 Vector ： 
 
 
  Vector< Integer> integerVector = new Vector< Integer>（）; 
 integerVector.add（Integer.MAX_VALUE）; 
 Integer i = integerVector.get（0）; 
  
 
I have the following Vector and at runtime I want to pass it an Integer, Character, or Float: 
public static Vector<Object> interestingValues = new Vector<Object>();
At the same time I want to get an Integer, Float, or Character from it, so there are two things:



Will they retain the specific Integer/Float/Character type in the Object Vector, or they all will be stored in the form of Object?
How can I retrieve Integer objects from this Vector?

解决方案
Casting:
Integer i=(Integer)interestingValues.get(0);
In case you have multiple types of objects inside the Vector you could check the type using instanceof:
Object o=interestingValues.get(0);
 if (o instanceof Integer){
      Integer i=(Integer)o;
 }else if (o instanceof Long){
      Long l=(Long)o;
 }
The third thing you can do to avoid the need ov casting objects to a particular type is using a typed Vector:
Vector <Integer> integerVector=new Vector<Integer>();
integerVector.add(Integer.MAX_VALUE);
Integer i=integerVector.get(0);


                        
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