如何用instanceof關鍵字來顯示Object類？

解決方法

這個例子讓displayObjectClass()方法來顯示類，傳遞到這個方法的對象作為參數。

import java.util.ArrayList;
import java.util.Vector;

public class Main {

public static void main(String[] args) {
   Object testObject = new ArrayList();
      displayObjectClass(testObject);
   }
   public static void displayObjectClass(Object o) {
      if (o instanceof Vector)
      System.out.println("Object was an instance 
      of the class java.util.Vector");
      else if (o instanceof ArrayList)
      System.out.println("Object was an instance of 
      the class java.util.ArrayList");
      else
      System.out.println("Object was an instance of the " 
      + o.getClass());
   }
}

結果

上麵的代碼示例將產生以下結果。

Object was an instance of the class java.util.ArrayList