Java Properties getProperty(key)用法及代碼示例

Properties類的getProperty(key)方法用於獲取映射到此鍵的值，該鍵作為參數傳遞到此Properties對象中。如果存在，此方法將獲取與此鍵對應的值，然後將其返回。如果沒有這樣的映射，則返回null。

用法:

public Object getProperty(String key)

參數：此方法接受參數鍵，該參數鍵的映射將在此Properties對象中檢查。

返回值：如果存在，此方法將返回與此鍵對應的取值。如果沒有這樣的映射，則返回null。

以下示例程序旨在說明getProperty(key)方法：

示例1:

// Java program to demonstrate 
// getProperty(key) 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")); 
  
        // Getting the value of Phone 
        System.out.println("Value of Phone: "
                           + properties 
                                 .getProperty("Phone")); 
    } 
}

輸出：

Properties: {Book=500, Mobile=5000, Pen=10, Clothes=400}
Value of Pen: null
Value of Phone: null

示例2:

// Java program to demonstrate 
// getProperty(key) 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")); 
  
        // Getting the value of 5 
        System.out.println("Value of 5: "
                           + properties 
                                 .getProperty("5")); 
    } 
}

輸出：

Current Properties: {3=1000RS, 2=500RS, 1=100RS}
Value of 1: null
Value of 5: null

參考：https://docs.oracle.com/javase/9/docs/api/java/util/Properties.html#getProperty-java.lang.String-

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注：本文由純淨天空篩選整理自Kirti_Mangal大神的英文原創作品 Properties getProperty(key) method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。