Java IdentityHashMap hashCode()用法及代码示例

Java中的java.util.IdentityHashMap.hashCode()方法用于获取特定此IdentityHashMap的哈希码值。映射由多个存储区组成，用于存储键值对。每个存储桶都有唯一的标识，当将键值对插入存储桶时，键的哈希码将与存储桶的标识符匹配，如果匹配，则存储对成功。哈希码就是这样工作的。

用法:

Identity_HashMap.hashCode()

参数：该方法不接受任何参数。

返回值：该方法返回Map的哈希码值。

以下程序用于说明java.util.IdentityHashMap.hashCode()方法的用法：

示例1:将字符串值映射到整数键。

// 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()); 
    } 
}

输出：

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

示例2:将整数值映射到字符串键。

// 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()); 
    } 
}

输出：

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

注意：可以对具有不同数据类型的变体和组合的任何类型的映射执行相同的操作。

相关用法

注：本文由纯净天空筛选整理自Chinmoy Lenka大神的英文原创作品 IdentityHashMap hashCode() Method in Java。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。