WeakHashMap类的java.util.WeakHashMap.size()方法用于获取映射的大小,该大小是指Map中键-值对或映射的数量。
用法:
WeaK_Hash_Map.size()
参数:该方法不带任何参数。
返回值:该方法返回Map的大小,这也意味着Map中存在的键值对的数量。
以下程序说明了java.util.WeakHashMap.size()方法:
示例1::
// Java code to illustrate the size() 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);
// Displaying the size of the map
System.out.println("The size of the map is " +
weak_hash.size());
}
}
输出:
Initial Mappings are: {30=You, 15=4, 10=Geeks, 25=Welcomes, 20=Geeks} The size of the map is 5
示例2:
// Java code to illustrate the size() 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);
// Displaying the size of the map
System.out.println("The size of the map is " +
weak_hash.size());
}
}
输出:
Initial Mappings are: {Welcomes=25, 4=15, You=30, Geeks=20} The size of the map is 4
注意:可以对具有不同数据类型的变化和组合的任何类型的映射执行相同的操作。
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注:本文由纯净天空筛选整理自Chinmoy Lenka大神的英文原创作品 WeakHashMap size() method in Java。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。