Java Properties clear()用法及代码示例

Java.util.Properties.clear()方法用于从此Properties实例中删除所有元素。使用clear()方法只能从属性中清除所有元素，而不会删除属性。换句话说，可以说clear()方法仅用于清空现有属性。

用法:

public void clear()

参数：该方法不带任何参数

返回值：该函数不返回任何值。

以下示例程序旨在说明Java.util.Properties.clear()方法。

示例1:

// Java code illustrating clear() method 
  
import java.util.*; 
  
class PropertiesDemo { 
    public static void main(String arg[]) 
    { 
        Properties gfg = new Properties(); 
        Set URL; 
        String str; 
  
        gfg.put("ide", 
                "ide.geeksforgeeks.org"); 
        gfg.put("contribute", 
                "contribute.geeksforgeeks.org"); 
        gfg.put("quiz", 
                "quiz.geeksforgeeks.org"); 
  
        // checking what's in table 
        System.out.println("Current Properties: "
                           + gfg.toString()); 
  
        System.out.println("\nClearing the Properties"); 
        gfg.clear(); 
  
        // checking what's in table now 
        System.out.println("New Properties: "
                           + gfg.toString()); 
    } 
}

输出：

Current Properties: {contribute=contribute.geeksforgeeks.org, quiz=quiz.geeksforgeeks.org, ide=ide.geeksforgeeks.org}

Clearing the Properties
New Properties: {}

示例2:

// Java code illustrating clear() method 
  
import java.util.*; 
  
class PropertiesDemo { 
    public static void main(String arg[]) 
    { 
        Properties gfg = new Properties(); 
        Set URL; 
        String str; 
  
        gfg.put(1, "Geeks"); 
        gfg.put(2, "GeeksforGeeks"); 
        gfg.put(3, "Geek"); 
  
        // checking what's in table 
        System.out.println("Current Properties: "
                           + gfg.toString()); 
  
        System.out.println("\nClearing the Properties"); 
        gfg.clear(); 
  
        // checking what's in table now 
        System.out.println("New Properties: "
                           + gfg.toString()); 
    } 
}

输出：

Current Properties: {3=Geek, 2=GeeksforGeeks, 1=Geeks}

Clearing the Properties
New Properties: {}

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

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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 clear() 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。