Java 中的 ConcurrentHashMap 元素()方法，带示例
原文:https://www . geeksforgeeks . org/concurrenthashmap-elements-method-in-Java-with-examples/
Java 中 ConcurrentHashMap 类的元素()方法用于获取表中存在的值的枚举。
语法:
Enumeration enu = ConcurrentHashMap.elements()
参数:该方法不取任何参数。
返回值:该方法返回哈希表值的枚举。
下面的程序用来说明 elements()方法的工作原理:
程序 1:
// Java code to illustrate the elements() method
import java.util.*;
import java.util.concurrent.*;
public class ConcurrentHashMap_Demo {
public static void main(String[] args)
{
// Creating an empty hash_map
ConcurrentHashMap<Integer, String>
hash_map = new ConcurrentHashMap<Integer,
String>();
// Mapping elements into the map
hash_map.put(10, "Geeks");
hash_map.put(15, "4");
hash_map.put(20, "Geeks");
hash_map.put(25, "Welcomes");
hash_map.put(30, "You");
// Displaying the hash_map
System.out.println("The Map is: " + hash_map);
// Creating an empty enumeration to store
Enumeration enu = hash_map.elements();
System.out.println("The enumeration of values are:");
// Displaying the Enumeration
while (enu.hasMoreElements()) {
System.out.println(enu.nextElement());
}
}
}
Output:
The Map is: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
The enumeration of values are:
Geeks
Welcomes
Geeks
You
4
程序 2:
// Java code to illustrate the elements() method
import java.util.*;
import java.util.concurrent.*;
public class ConcurrentHashMap_Demo {
public static void main(String[] args)
{
// Creating an empty hash_map
ConcurrentHashMap<String, Integer>
hash_map = new ConcurrentHashMap<String,
Integer>();
// Inserting elements into the map
hash_map.put("Geeks", 10);
hash_map.put("4", 15);
hash_map.put("Geeks", 20);
hash_map.put("Welcomes", 25);
hash_map.put("You", 30);
// Displaying the hash_map
System.out.println("The Map is: " + hash_map);
// Creating an empty enumeration to store
Enumeration enu = hash_map.elements();
System.out.println("The enumeration of values are:");
// Displaying the Enumeration
while (enu.hasMoreElements()) {
System.out.println(enu.nextElement());
}
}
}
Output:
The Map is: {4=15, Geeks=20, You=30, Welcomes=25}
The enumeration of values are:
15
20
30
25
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