java.util.Vector.isEmpty()



描述

所述isEmpty()方法被用来测试该向量没有组件。

声明

以下是java.util.Vector.isEmpty()方法的声明

public boolean isEmpty()

参数

NA

返回值

当且仅当此向量没有组件时,返回值为true,即其大小为零。否则返回false。

异常

NA

实例

以下示例显示了java.util.Vector.isEmpty()方法的用法。

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