Java 中的属性 getProperty(key,defaultValue)方法,示例
原文:https://www . geesforgeks . org/properties-getpropertykey-defaultvalue-method-in-Java-with-examples/
属性类 的 getProperty(key,defaultValue) 方法用于获取映射到这个 key 的值,作为参数传递到这个 Properties 对象中。此方法将获取该键的相应值(如果存在),并返回它。如果没有这样的映射,那么它返回缺省值。
语法:
公共字符串 getProperty(String key,String defaultValue)
参数:该方法接受两个参数:
- 键:要在该属性对象中检查其映射。
- 默认值:这是键的默认映射
返回:该方法返回与该键对应的值(如果存在)。如果没有这样的映射,那么它返回缺省值。
下面的程序说明了 getProperty(键,默认值)方法:
程序 1:
// Java program to demonstrate
// getProperty(key, defaultValue) 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());
// Getting the value of Pen
System.out.println("Value of Pen: "
+ properties
.getProperty("Pen", 200));
// Getting the value of Phone
System.out.println("Value of Phone: "
+ properties
.getProperty("Phone", 200));
}
}
输出:
Properties: {Book=500, Mobile=5000, Pen=10, Clothes=400}
Value of Pen: 10
Value of Phone: 200
程序二:
// Java program to demonstrate
// getProperty(key, defaultValue) 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(1, "100RS");
properties.put(2, "500RS");
properties.put(3, "1000RS");
// Print Properties details
System.out.println("Current Properties: "
+ properties.toString());
// Getting the value of 1
System.out.println("Value of 1: "
+ properties
.getProperty(1, "200RS"));
// Getting the value of 5
System.out.println("Value of 5: "
+ properties
.getProperty(5, "200RS"));
}
}
输出:
Current Properties: {3=1000RS, 2=500RS, 1=100RS}
Value of 1: 100RS
Value of 5: 200RS
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