java.util.Vector.isEmpty() 方法

描述

isEmpty() 方法用于测试该向量是否没有分量。

声明

以下是 java.util.Vector.isEmpty() 方法的声明

public boolean isEmpty()

参数

NA

返回值

当且仅当这个向量没有分量，即它的大小为零时，返回值为真。否则返回假。

异常

NA

示例

下面的例子展示了 java.util.Vector.isEmpty() 方法的使用。

package com.tutorialspoint;

import java.util.Vector;

public class VectorDemo {
   public static void main(String[] args) {

      // create an empty Vector vec with an initial capacity of 4      
      Vector<Integer> vec = new Vector<Integer>(4);

      // let us test the vector
      System.out.println("The vector does not have any element"); 
      System.out.println("The vector is empty: "+vec.isEmpty()); 

      // use add() method to add elements in the vector
      vec.add(4);
      vec.add(3);
      vec.add(2);
      vec.add(1);

      // let us test the vector again
      System.out.println("The vector has elements"); 
      System.out.println("The vector is empty: "+vec.isEmpty()); 
   }     
}

让我们编译并运行上面的程序，这将产生以下结果.

The vector does not have any element
The vector is empty: true
The vector has elements
The vector is empty: false