Java中的IdentityHashMap equals()方法

Java中的Java .util.IdentityHashMap.equals() 方法用于检查两个映射之间的相等性。它验证作为参数传递的一个映射的元素是否等于该映射的元素。

句法：

ihashmap1.equals(ihashmap2)

参数：该方法接受一个身份哈希映射类型的参数ihashmap2 ，并引用要与此哈希映射检查其相等性的映射。

返回值：如果相等对两个对象映射都成立，则该方法返回 true，否则返回 false。

下面的程序说明了Java.util.IdentityHashMap.equals() 方法的工作：
方案一：

// Java code to illustrate the equals() method
import java.util.*;
  
public class Identity_Hash_Map_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty IdentityHashMap
        IdentityHashMap identity_hash1 = 
                   new IdentityHashMap();
        IdentityHashMap identity_hash2 = 
                   new IdentityHashMap();
  
        // Mapping string values to int keys
        identity_hash1.put(10, "Geeks");
        identity_hash1.put(15, "4");
        identity_hash1.put(20, "Geeks");
        identity_hash1.put(25, "Welcomes");
        identity_hash1.put(30, "You");
          
        // Mapping string values to int keys
        identity_hash2.put(10, "Geeks");
        identity_hash2.put(15, "4");
        identity_hash2.put(20, "Geeks");
        identity_hash2.put(25, "Welcomes");
        identity_hash2.put(30, "You");
  
        // Displaying the IdentityHashMap
        System.out.println("First Map: "
                        + identity_hash1);
  
        // Displaying the final IdentityHashMap
        System.out.println("Second Map: "
                        + identity_hash2);
                          
        // Displaying the equality
        System.out.println("Equality: "+
                  identity_hash1.equals(identity_hash2));
    }
}

输出：

First Map: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
Second Map: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
Equality: true

方案二：

// Java code to illustrate the equals() method
import java.util.*;
  
public class Identity_Hash_Map_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty IdentityHashMap
        IdentityHashMap identity_hash1 = 
                   new IdentityHashMap();
        IdentityHashMap identity_hash2 = 
                   new IdentityHashMap();
  
        // Mapping string values to int keys
        identity_hash1.put(10, "Geeks");
        identity_hash1.put(15, "4");
        identity_hash1.put(20, "Geeks");
        identity_hash1.put(25, "Welcomes");
        identity_hash1.put(30, "You");
          
        // Mapping string values to int keys
        identity_hash2.put(10, "Geeks");
        identity_hash2.put(15, "4");
        identity_hash2.put(20, "Geek");
        identity_hash2.put(25, "Welcomes");
        identity_hash2.put(30, "You");
  
        // Displaying the IdentityHashMap
        System.out.println("First Map: "
                        + identity_hash1);
  
        // Displaying the final IdentityHashMap
        System.out.println("Second Map: "
                        + identity_hash2);
                          
        // Displaying the equality
        System.out.println("Equality: "+
                  identity_hash1.equals(identity_hash2));
    }
}

输出：

First Map: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
Second Map: {10=Geeks, 30=You, 20=Geek, 25=Welcomes, 15=4}
Equality: false