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等价性。它验证作为参数传递的一个映射的元素是否等于此映射的元素。

语法：

ihashmap1.equals(ihashmap2)

参数： 该方法接受一个标识哈希 map 类型的参数 ihashmap2，并引用其与此哈希 map 要检查等价性的映射。

返回值： 如果两个对象映射的等价性成立，该方法返回 true，否则返回 false。

以下程序说明了 java.util.IdentityHashMap.equals() 方法的工作原理：
程序 1：

// 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<Integer, String> identity_hash1 = 
                   new IdentityHashMap<Integer, String>();
        IdentityHashMap<Integer, String> identity_hash2 = 
                   new IdentityHashMap<Integer, String>();
  
        // 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));
    }
}

第一张地图：{10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
第二张地图：{10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
平等：真

程序 2：

// Java代码演示equals()方法
import java.util.*;
  
public class Identity_Hash_Map_Demo {
    public static void main(String[] args)
    {
  
        // 创建一个空的IdentityHashMap
        IdentityHashMap<Integer, String> identity_hash1 = 
                   new IdentityHashMap<Integer, String>();
        IdentityHashMap<Integer, String> identity_hash2 = 
                   new IdentityHashMap<Integer, String>();
  
        // 将字符串值映射到int键上
        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");
          
        // 将字符串值映射到int键上
        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");
  
        // 显示IdentityHashMap
        System.out.println("第一张地图："
                        + identity_hash1);
  
        // 显示最终的IdentityHashMap
        System.out.println("第二张地图："
                        + identity_hash2);
                          
        // 显示相等性
        System.out.println("相等性：" +
                  identity_hash1.equals(identity_hash2));
    }
}

第一张地图：{10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
第二张地图：{10=Geeks, 30=You, 20=Geek, 25=Welcomes, 15=4}
相等性：false