Java中的属性 isEmpty() 方法及示例

Properties 类的isEmpty()方法用于检查此 Properties 对象是否为空。

句法：

public boolean isEmpty()

参数：此方法不接受任何参数

返回：此方法返回一个布尔值，说明此 Properties 对象是否为空。

下面的程序显示了 int isEmpty() 方法的实现。

方案一：

// Java code to show the implementation of
// isEmpty method
  
import java.util.*;
public class GfG {
  
    // Main method
    public static void main(String[] args)
    {
  
        // Create a properties and add some values
        Properties properties = new Properties();
        properties.put("Pen", 10);
        properties.put("Book", 500);
        properties.put("Clothes", 400);
        properties.put("Mobile", 5000);
  
        // Print Properties details
        System.out.println("Properties: "
                           + properties.toString());
  
        // Checking if the Properties is empty
        System.out.println("Is Properties empty: "
                           + properties.isEmpty());
    }
}

输出：

Properties: {Book=500, Mobile=5000, Pen=10, Clothes=400}
Is Properties empty: false

方案二：

// Java program to demonstrate
// isEmpty() method.
  
import java.util.*;
  
public class GFG {
  
    // Main method
    public static void main(String[] args)
    {
  
        // Create a properties and add some values
        Properties properties = new Properties();
  
        // Print Properties details
        System.out.println("Current Properties: "
                           + properties.toString());
  
        // Checking if the Properties is empty
        System.out.println("Is Properties empty: "
                           + properties.isEmpty());
    }
}

输出：

Current Properties: {}
Is Properties empty: true

参考资料：https://docs.oracle.com/javase/9/docs/api/ Java/util/Properties.html#isEmpty–