Java中的属性 keys() 方法及示例
Properties 类的keys()方法用于获取此 Properties 对象中键的枚举。此枚举可用于按顺序遍历和迭代键。
句法:
public Enumeration keys()
参数:此方法不接受任何参数
返回:此方法按顺序返回此 Properties 对象的键的枚举。
下面的程序显示了 int keys() 方法的实现。
方案一:
// 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
方案二:
// 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
参考资料:https://docs.oracle.com/javase/9/docs/api/ Java/util/Properties.html#keys–