boolean isEmpty()
描述 (Description)
isEmpty()方法用于测试此向量是否没有组件。
声明 (Declaration)
以下是java.util.Vector.isEmpty()方法的声明
public boolean isEmpty()
参数 (Parameters)
NA
返回值 (Return Value)
当且仅当此向量没有组件时，返回值为true，即它的大小为零。否则返回false。
异常 (Exception)
NA
例子 (Example)
以下示例显示了java.util.Vector.isEmpty（）方法的用法。
package com.iowiki;
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
