Java 中的属性键()方法，示例
原文:https://www . geesforgeks . org/properties-keys-method-in-Java-with-examples/
属性类 的键()方法用于获取该属性对象中键的枚举。此枚举可用于顺序遍历和迭代键。
语法:
public Enumeration keys()
参数:该方法不接受参数
返回:该方法依次返回该属性对象的键的 枚举 。
下面的程序展示了 int keys()方法的实现。
程序 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
程序二:
// 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
参考文献:https://docs . Oracle . com/javase/9/docs/API/Java/util/properties . html # keys–
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