Java中的java.util.WeakHashMap.entrySet()方法用於根據Map中包含的相同元素創建集合。它本質上返回弱哈希映射的集合視圖,或者我們可以創建一個新集合並將映射元素存儲到其中。
用法:
weak_hash_map.entrySet()
參數:該方法不帶任何參數。
返回值:該方法返回與Map具有相同元素的集合。
以下示例程序旨在說明java.util.WeakHashMap.entrySet()方法:
示例1:將字符串值映射到整數鍵。
// Java code to illustrate the entrySet() method
import java.util.*;
public class Weak_Hash_Map_Demo {
public static void main(String[] args)
{
// Creating an empty WeakHashMap
Map<Integer, String> weak_hash = new WeakHashMap<Integer, String>();
// Mapping string values to int keys
weak_hash.put(10, "Geeks");
weak_hash.put(15, "4");
weak_hash.put(20, "Geeks");
weak_hash.put(25, "Welcomes");
weak_hash.put(30, "You");
// Displaying the WeakHashMap
System.out.println("Initial Mappings are: " + weak_hash);
// Using entrySet() to get the set view
System.out.println("The set is: " + weak_hash.entrySet());
}
}
輸出:
Initial Mappings are: {30=You, 15=4, 10=Geeks, 25=Welcomes, 20=Geeks} The set is: [30=You, 15=4, 10=Geeks, 25=Welcomes, 20=Geeks]
示例2:將整數值映射到字符串鍵。
// Java code to illustrate the entrySet() method
import java.util.*;
public class Weak_Hash_Map_Demo {
public static void main(String[] args)
{
// Creating an empty WeakHashMap
Map<String, Integer> weak_hash = new WeakHashMap<String, Integer>();
// Mapping int values to string keys
weak_hash.put("Geeks", 10);
weak_hash.put("4", 15);
weak_hash.put("Geeks", 20);
weak_hash.put("Welcomes", 25);
weak_hash.put("You", 30);
// Displaying the WeakHashMap
System.out.println("Initial Mappings are: " + weak_hash);
// Using entrySet() to get the set view
System.out.println("The set is: " + weak_hash.entrySet());
}
}
輸出:
Initial Mappings are: {Welcomes=25, 4=15, You=30, Geeks=20} The set is: [Welcomes=25, 4=15, You=30, Geeks=20]
注意:可以對具有不同數據類型的變化和組合的任何類型的映射執行相同的操作。
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注:本文由純淨天空篩選整理自Chinmoy Lenka大神的英文原創作品 WeakHashMap entrySet() Method in Java。非經特殊聲明,原始代碼版權歸原作者所有,本譯文未經允許或授權,請勿轉載或複製。