IdentityHashMap類putAll()方法 (IdentityHashMap Class putAll() method)
putAll() method is available in java.util package.
putAll()方法在java.util包中可用。
putAll() method is used to copy all of the entry (key-value pairs) that exists from the given map (m) and paste it into this IdentityHashMap.
putAll()方法用于復制給定映射(m)中存在的所有條目(鍵值對)，并將其粘貼到此IdentityHashMap中。
putAll() 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.
putAll()方法是一種非靜態方法，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。
putAll() method may throw an exception at the time of copying key-value pairs.
在復制鍵值對時， putAll()方法可能會引發異常。
NullPointerException: This exception may throw when the given parameter is null exists.
NullPointerException ：當給定參數為null時，可能引發此異常。
Syntax:
句法：
public void putAll(Map m);
Parameter(s):
參數：
Map m – represents the Map object that contains key-value pairs to be copied from.
Map m –表示Map對象，其中包含要從中復制的鍵/值對。
Return value:
返回值：
The return type of the method is void, it returns nothing.
該方法的返回類型為void ，不返回任何內容。
Example:
例：
// Java program to demonstrate the example
// of void putAll(Map m) method of IdentityHashMap
import java.util.*;
public class PutAllOfIdentityHashMap {
public static void main(String[] args) {
// Instantiates a IdentityHashMap object
Map < Integer, String > map = new IdentityHashMap < Integer, String > ();
Map < Integer, String > put_map = new IdentityHashMap < Integer, String > ();
// By using put() method is to add
// key-value pairs in a IdentityHashMap
map.put(10, "C");
map.put(20, "C++");
map.put(50, "JAVA");
map.put(40, "PHP");
map.put(30, "SFDC");
// Display IdentityHashMap
System.out.println("IdentityHashMap: " + map);
// By using putAll() method is to
// copy all of the elements of the given
// object and paste it in an another object
put_map.putAll(map);
// Display put_map IdentityHashMap
System.out.print("put_map.putAll(map): " + put_map);
}
}
Output
輸出量
IdentityHashMap: {20=C++, 40=PHP, 50=JAVA, 30=SFDC, 10=C}
put_map.putAll(map): {20=C++, 40=PHP, 50=JAVA, 30=SFDC, 10=C}
翻譯自: https://www.includehelp.com/java/identityhashmap-putall-method-with-example.aspx
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