Java中的java.util.IdentityHashMap.entrySet()方法用于创建映射中包含的相同元素的集合。它基本上返回了哈希映射的map集合，或者我们可以创建一个新集合并将地图元素存储到它们中。
句法：
Identity_HashMap.entrySet()
参数：该方法不带任何参数。
返回值：该方法返回一个具有与map相同元素的集合。
下面的程序说明了java.util.IdentityHashMap.entrySet（）方法
程序1：将字符串值映射到整数键。
// Java code to illustrate the entrySet() 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);
// Using entrySet() to get the set view
System.out.println("The set is: " +
identity_hash.entrySet());
}
}
输出：
Initial Mappings are: {10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4}
The set is: [10=Geeks, 30=You, 20=Geeks, 25=Welcomes, 15=4]
程序2：将整数值映射到字符串键。
// Java code to illustrate the entrySet() method
import java.util.*;
public class Identity_Hash_Map_Demo {
public static void main(String[] args)
{
// Creating an empty IdentityHashMap
IdentityHashMap<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);
// Using entrySet() to get the set view
System.out.println("The set is: " +
identity_hash.entrySet());
}
}
输出：
Initial Mappings are: {Geeks=20, Welcomes=25, You=30, 4=15}
The set is: [Geeks=20, Welcomes=25, You=30, 4=15]