IdentityHashMap类的put()方法 (IdentityHashMap Class put() method)

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

  put()方法在java.util包中可用。

• put() method is used to set the given value element (val_ele) with the given key element (key_ele) when no value element associated previously with the given key otherwise it replaces the old value element with the given new value element (val_ele) for the given key element (key_ele) when any value element associated with the given key previously.

  当以前没有与给定键相关联的值元素时，使用put()方法将给定值元素(val_ele)设置为给定键元素(key_ele)，否则将旧值元素替换为给定新值元素(val_ele)当先前与给定键关联的任何值元素时，给定键元素(key_ele)。

• put() 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.

  put()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。

• put() method does not throw an exception at the time of replacing the value element if exists.

  put()方法在替换value元素(如果存在)时不会引发异常。

Syntax:

句法：

    public Value put(Key key_ele, Value val_ele);

Parameter(s):

参数：

• Key key_ele – represents the key element with which the given value is to be linked.

  Key key_ele –表示与给定值链接的键元素。

• Value val_ele – represents the value element to be linked with the given key element (key_ele).

  值val_ele –表示要与给定键元素(key_ele)链接的value元素。

Return value:

返回值：

The return type of the method is Value, it returns the old value element linked with the given key element (key_ele) when exists otherwise it returns null.

该方法的返回类型为Value ，如果存在则返回与给定键元素(key_ele)链接的旧value元素，否则返回null。

Example:

例：

// Java program to demonstrate the example
// of Value put(Key key_ele, Value val_ele)
// method of IdentityHashMap
import java.util.*;
public class PutOfIdentityHashMap {public static void main(String[] args) {// Instantiates a IdentityHashMap object
Map < Integer, String > 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 put() method is to
// replace the existing value associated
// for the given key element with the
// new value element
map.put(50, "Microservices");
// Display Modified IdentityHashMap
System.out.print("IdentityHashMap: " + map);
}
}

Output

输出量

IdentityHashMap: {20=C++, 40=PHP, 50=JAVA, 30=SFDC, 10=C}
IdentityHashMap: {20=C++, 40=PHP, 50=Microservices, 30=SFDC, 10=C}

翻译自: https://www.includehelp.com/java/identityhashmap-put-method-with-example.aspx