Java Properties keys()用法及代码示例

Properties类的keys()方法用于获取此Properties对象中的键的枚举。此枚举可用于顺序遍历和迭代键。

用法:

public Enumeration keys()

参数：此方法不接受任何参数

返回值：此方法顺序返回此Properties对象的键的Enumeration。

下面的程序显示int keys()方法的实现。

示例1:

// Java code to show the implementation of 
// keys() 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()); 
  
        // Creating an empty enumeration to store 
        Enumeration enu = properties.keys(); 
  
        System.out.println("The enumeration of keys are:"); 
  
        // Displaying the Enumeration 
        while (enu.hasMoreElements()) { 
            System.out.println(enu.nextElement()); 
        } 
    } 
}

输出：

Properties: {Book=500, Mobile=5000, Pen=10, Clothes=400}
The enumeration of keys are:
Book
Mobile
Pen
Clothes

示例2:

// Java program to demonstrate 
// keys() 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(); 
  
        // Inserting elements into the properties 
        properties.put("Geeks", 10); 
        properties.put("4", 15); 
        properties.put("Geeks", 20); 
        properties.put("Welcomes", 25); 
        properties.put("You", 30); 
  
        // Print Properties details 
        System.out.println("Current Properties: "
                           + properties.toString()); 
  
        // Creating an empty enumeration to store 
        Enumeration enu = properties.keys(); 
  
        System.out.println("The enumeration of keys are:"); 
  
        // Displaying the Enumeration 
        while (enu.hasMoreElements()) { 
            System.out.println(enu.nextElement()); 
        } 
    } 
}

输出：

Current Properties: {You=30, Welcomes=25, 4=15, Geeks=20}
The enumeration of keys are:
You
Welcomes
4
Geeks

参考：https://docs.oracle.com/javase/9/docs/api/java/util/Properties.html#keys–

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注：本文由纯净天空筛选整理自Kirti_Mangal大神的英文原创作品 Properties keys() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。