Java Dictionary get()用法及代碼示例

字典類的get()方法用於檢索或獲取由參數中提到的特定鍵映射的值。當字典中不包含此類鍵的映射時，它將返回NULL。

用法:

DICTIONARY.get(Object key_element)

參數：該方法采用對象類型的一個參數key_element，表示應該獲取其關聯值的鍵。

返回值：該方法返回與參數中的key_element關聯的值。

以下程序用於說明java.util.Dictionary.get()方法的用法：
示例1:

// Java code to illustrate the get() method 
import java.util.*; 
  
public class Dictionary_Demo { 
    public static void main(String[] args) 
    { 
  
        // Creating an empty Dictionary 
        Dictionary<Integer, String> dict 
            = new Hashtable<Integer, String>(); 
  
        // Inserting the values into dictionary 
        dict.put(10, "Geeks"); 
        dict.put(15, "4"); 
        dict.put(20, "Geeks"); 
        dict.put(25, "Welcomes"); 
        dict.put(30, "You"); 
  
        // Displaying the Dictionary 
        System.out.println("Initial Dictionary is: " + dict); 
  
        // Getting the value of 25 
        System.out.println("The Value is: " + dict.get(25)); 
  
        // Getting the value of 10 
        System.out.println("The Value is: " + dict.get(10)); 
    } 
}

輸出：

Initial Dictionary is: {10=Geeks, 20=Geeks, 30=You, 15=4, 25=Welcomes}
The Value is: Welcomes
The Value is: Geeks

示例2:

// Java code to illustrate the get() method 
import java.util.*; 
  
public class Dictionary_Demo { 
    public static void main(String[] args) 
    { 
  
        // Creating an empty Dictionary 
        Dictionary<String, Integer> dict 
            = new Hashtable<String, Integer>(); 
  
        // Inserting the values into dictionary 
        dict.put("Geeks", 10); 
        dict.put("4", 15); 
        dict.put("Geeks", 20); 
        dict.put("Welcomes", 25); 
        dict.put("You", 30); 
  
        // Displaying the Dictionary 
        System.out.println("Initial Dictionary is: "
                           + dict); 
  
        // Getting the value of 25 
        System.out.println("The Value is: "
                           + dict.get("Geeks")); 
  
        // Getting the value of 10 
        System.out.println("The Value is: "
                           + dict.get(20)); 
    } 
}

輸出：

Initial Dictionary is: {You=30, Welcomes=25, 4=15, Geeks=20}
The Value is: 20
The Value is: null

相關用法

注：本文由純淨天空篩選整理自Chinmoy Lenka大神的英文原創作品 Dictionary get() 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。