Java中的WeakHashMap get（）方法-yiteyi-C++库

爪哇。util。WeakHashMap。WeakHashMap类的get（）方法用于检索或获取由参数中提到的特定键映射的值。当映射不包含密钥的此类映射时，它返回NULL。

null

语法：

WeakHashMap.get(Object key_element)

参数： 该方法采用一个参数 关键元素 对象类型，并指其关联值应被提取的键。

返回值： 该方法返回与 关键元素 在参数中。

下面的程序演示了java的工作原理。util。WeakHashMap。get（）方法：

项目1：

                     // Java code to illustrate the get() 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);                   
                             
                                         // Getting the value of 25                   
                                         System.out.println(                               "The Value is: "                               + weak_hash.get(                               25                               ));                   
                             
                                         // Getting the value of 10                   
                                         System.out.println(                               "The Value is: "                               + weak_hash.get(                               10                               ));                   
                                         }                   
                     }                   

输出：

Initial Mappings are: {30=You, 15=4, 10=Geeks, 25=Welcomes, 20=Geeks}
The Value is: Welcomes
The Value is: Geeks

项目2：

                     // Java code to illustrate the get() 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);                   
                             
                                         // Getting the value of "Geeks"                   
                                         System.out.println(                               "The Value is: "                               + weak_hash.get(                               "Geeks"                               ));                   
                             
                                         // Getting the value of "You"                   
                                         System.out.println(                               "The Value is: "                               + weak_hash.get(                               "You"                               ));                   
                                         }                   
                     }                   

输出：

Initial Mappings are: {Welcomes=25, 4=15, You=30, Geeks=20}
The Value is: 20
The Value is: 30

注：相同的操作可以在不同数据类型的变化和组合的任何类型的映射中执行。

文章版权归作者所有，未经允许请勿转载。

THE END

Java