weakhashmap

WeakHashMap類entrySet()方法 (WeakHashMap Class entrySet() method)

• entrySet() method is available in java.util package.

  entrySet()方法在java.util包中可用。

• entrySet() method is used to retrieve the mappings that exist in this map to be viewed in a collection.

  entrySet()方法用于檢索此映射中存在的映射，以在集合中進行查看。

• entrySet() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  entrySet()方法是一個非靜態方法，只能通過類對象訪問，如果嘗試使用類名稱訪問該方法，則會收到錯誤消息。

• entrySet() method does not throw an exception at the time of viewing elements in a collection.

  在查看集合中的元素時， entrySet()方法不會引發異常。

Syntax:

句法：

    public Set entrySet();

Parameter(s):

參數：

• It does not accept any parameter.

  它不接受任何參數。

Return value:

返回值：

The return type of the method is Set, it returns existing mappings in this map in a collection view.

方法的返回類型為Set ，它在集合視圖中返回此映射中的現有映射。

Example:

例：

// Java program to demonstrate the example 
// of Set entrySet() method of WeakHashMap 
import java.util.*;
public class EntrySetOfWeakHashMap {
public static void main(String[] args) {
// Instantiates a WeakHashMap object
Map < Integer, String > map = new WeakHashMap < Integer, String > ();
// By using put() method is to add
// key-value pairs in a WeakHashMap
map.put(10, "C");
map.put(20, "C++");
map.put(50, "JAVA");
map.put(40, "PHP");
map.put(30, "SFDC");
//Display WeakHashMap
System.out.println("WeakHashMap: " + map);
// By using entrySet() method is to
// return the entry exists in this 
// WeakHashMap to be viewed in a Set
Set s = map.entrySet();
// Display set view
System.out.print("map.entrySet(): ");
System.out.println(s);
}
}

Output

輸出量

WeakHashMap: {30=SFDC, 40=PHP, 10=C, 20=C++, 50=JAVA}
map.entrySet(): [30=SFDC, 40=PHP, 10=C, 20=C++, 50=JAVA]

翻譯自: https://www.includehelp.com/java/weakhashmap-entryset-method-with-example.aspx

weakhashmap