HashMap类entrySet()方法 (HashMap 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 return an entry (key-value pairs) that exists in this HashMap to be viewed in a Set.

  entrySet()方法用于返回此HashMap中存在的条目(键值对)，以在Set中进行查看。

• 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()方法是一个非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。

• entrySet() method does not throw an exception at the time of returning entry set.

  返回条目集时， entrySet()方法不会引发异常。

Syntax:

句法：

public Set entrySet();

Parameter(s):

参数：

• It does not accept any parameter.

  它不接受任何参数。

Return value:

返回值：

The return type of the method is Set, it returns mappings exist in this HashMap to be viewed in a Set.

方法的返回类型为Set ，它返回此HashMap中存在的映射以在Set中进行查看。

Example:

例：

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

Output

输出量

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

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