java entryset_Java HashMap entrySet（）方法与示例

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]

翻译自: https://www.includehelp.com/java/hashmap-entryset-method-with-example.aspx

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