hashtable put_Java Hashtable put（）方法与示例

爱被打了一巴掌 2023-03-05 12:53 17阅读 0赞

hashtable put

## 哈希表类put()方法 **(**Hashtable 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 put the given key element (key\_ele) to the given value element (val\_ele).
    
    **put()方法**用于将给定的键元素(key\_ele)放入给定的值元素(val\_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** may throw an exception at the time of put key-value pairs.
    
    **put()方法**在放置键/值对时可能会引发异常。
    
    **NullPointerException**: This exception may throw when any of the given parameters is null exists.
    
    **NullPointerException** ：当任何给定参数为null时，可能引发此异常。

**Syntax:**

**句法：**

public Value put(Key key_ele , Value val_ele);

**Parameter(s):**

**参数：**

*  Key key\_ele – represent the key element (key\_ele) in this Hashtable.
    
    Key key\_ele –表示此哈希表中的键元素(key\_ele)。
 *  Value val\_ele – represent the value element (val\_ele) in this Hashtable.
    
    值val\_ele –表示此哈希表中的值元素(val\_ele)。

**Return value:**

**返回值：**

The return type of the method is Value, it returns old value 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)链接的旧值，否则返回null。

**Example:**

**例：**

// Java program to demonstrate the example 
    // of Value put(Key key_ele , Value val_ele)
    // method of Hashtable 
    
    import java.util.*;
    
    public class PutOfHashtable {
        
        public static void main(String[] args) {
        
    
            //Instantiate a hashtable object  
            Hashtable ht = new Hashtable();
    
            // By using put() method is to
            // add the linked values in an
            // Hashtable ht
            ht.put(10, "C");
            ht.put(20, "C++");
            ht.put(30, "JAVA");
            ht.put(40, "PHP");
            ht.put(50, "SFDC");
    
            // Display Hashtable
            System.out.println("Hashtable :" + ht);
    
            // By using put() method is to replace
            // the value element exists on the key
            // element in this Hashtable
            ht.put(30, "Microservices");
    
            // Display Modified Hashtable
            System.out.println("ht.put(30,Microservices) :" + ht);
        }
    }

**Output**

**输出量**

Hashtable :{10=C, 20=C++, 30=JAVA, 40=PHP, 50=SFDC}
    ht.put(30,Microservices) :{10=C, 20=C++, 30=Microservices, 40=PHP, 50=SFDC}

> 翻译自: [https://www.includehelp.com/java/hashtable-put-method-with-example.aspx][https_www.includehelp.com_java_hashtable-put-method-with-example.aspx]

hashtable put

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