java treemap

TreeMap類putAll()方法 (TreeMap 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 the key-value pairs from the given map (m) and paste it into this map.

  putAll()方法用于復制給定映射(m)中的所有鍵值對，并將其粘貼到此映射中。

• 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 replacing mappings.

  putAll()方法可能會在替換映射處引發異常。

  • ClassCastException: This exception may throw when the given map (m) elements protect it from being saved in this Map.ClassCastException ：當給定的map(m)元素防止將其保存在此Map中時，可能會拋出此異常。
  • 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 mappings to be saved in this TreeMap.

  映射m –表示要保存在此TreeMap中的映射。

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 TreeMap import java.util.*;public class PutAllOfTreeMap {public static void main(String[] args) {// Instantiates two TreeMapTreeMap < Integer, String > tm1 = new TreeMap < Integer, String > ();TreeMap < Integer, String > tm2 = new TreeMap < Integer, String > ();// By using put() method is// to put the key-value pairs in// treemap tm1tm1.put(1, "C");tm1.put(4, "C++");tm1.put(3, "Java");tm1.put(2, "Php");// By using put() method is// to put the key-value pairs in// treemap tm2tm2.put(1, "SQL");tm2.put(2, "DBMS");// Display TreeMap tm1System.out.println("tm1: " + tm1);// By using putAll() method is to// put all the elements of tm2 in tm1tm1.putAll(tm2);// Display updated TreeMap tm1System.out.println("tm1.putAll(tm2): " + tm1);} }

Output

輸出量

tm1: {1=C, 2=Php, 3=Java, 4=C++} tm1.putAll(tm2): {1=SQL, 2=DBMS, 3=Java, 4=C++}

翻譯自: https://www.includehelp.com/java/treemap-putall-method-with-example.aspx

java treemap

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