Java IdentityHashMap hashCode()用法及代碼示例

Java中的java.util.IdentityHashMap.hashCode()方法用於獲取特定此IdentityHashMap的哈希碼值。映射由多個存儲區組成，用於存儲鍵值對。每個存儲桶都有唯一的標識，當將鍵值對插入存儲桶時，鍵的哈希碼將與存儲桶的標識符匹配，如果匹配，則存儲對成功。哈希碼就是這樣工作的。

用法:

Identity_HashMap.hashCode()

參數：該方法不接受任何參數。

返回值：該方法返回Map的哈希碼值。

以下程序用於說明java.util.IdentityHashMap.hashCode()方法的用法：

示例1:將字符串值映射到整數鍵。

// Java code to illustrate the hashCode() method 
import java.util.*; 
  
public class Identity_Hash_Map_Demo { 
    public static void main(String[] args) 
    { 
  
        // Creating an empty IdentityHashMap 
        IdentityHashMap<Integer, String> identity_hash =  
                   new IdentityHashMap<Integer, String>(); 
  
        // Mapping string values to int keys 
        identity_hash.put(10, "Geeks"); 
        identity_hash.put(15, "4"); 
        identity_hash.put(20, "Geeks"); 
        identity_hash.put(25, "Welcomes"); 
        identity_hash.put(30, "You"); 
  
        // Displaying the IdentityHashMap 
        System.out.println("Initial Mappings are: "
                           + identity_hash); 
  
        // Getting the hashcode value for the map 
        System.out.println("The hashcode value of the map: "
                                + identity_hash.hashCode()); 
    } 
}

輸出：

Initial Mappings are: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
The hashcode value of the map: 2043437408

示例2:將整數值映射到字符串鍵。

// Java code to illustrate the hashCode() method 
import java.util.*; 
  
public class Identity_Hash_Map_Demo { 
    public static void main(String[] args) 
    { 
  
        // Creating an empty IdentityHashMap 
        Map<String, Integer> identity_hash =  
                    new IdentityHashMap<String, Integer>(); 
  
        // Mapping int values to string keys 
        identity_hash.put("Geeks", 10); 
        identity_hash.put("4", 15); 
        identity_hash.put("Geeks", 20); 
        identity_hash.put("Welcomes", 25); 
        identity_hash.put("You", 30); 
  
        // Displaying the IdentityHashMap 
        System.out.println("Initial Mappings are: "
                           + identity_hash); 
  
        // Getting the hashcode value for the map 
        System.out.println("The hashcode value of the map: "
                                + identity_hash.hashCode()); 
    } 
}

輸出：

Initial Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15}
The hashcode value of the map: 751311572

注意：可以對具有不同數據類型的變體和組合的任何類型的映射執行相同的操作。

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 IdentityHashMap hashCode() Method in Java。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。