Java Map Get Value By Key Example

Example 1 : Java Map get Value By Key – Key is present

In this example we will create HashMap with Integer and String mapping . We add element in map using put method . we use java HashMapget method to get value by key . We will try to get value of key 1 and 4 here , because key is present in HashMap, so java HashMap get method returns corresponding values of key .  Let’s see java program for map get value by key java .

import java.util.HashMap;
import java.util.Map;

public class HashMapGetValueBykey {
	
	public static void main(String[] args) {

		Map<Integer,String> hm = new HashMap<Integer,String>();

		hm.put(1,"java");
		hm.put(2, "vogue");
		hm.put(3,"welcomes");
		hm.put(4,"you");

		/*
		* Returns the value to which the specified
		* key is mapped, or null if this map contains
		*  no mapping for the key.
		*/

		System.out.println("get value by key: 1 is  = "+hm.get(1));
		System.out.println("get value by key: 4 is = "+hm.get(4));

		}

}

Output:

get value by key: 1 is  = java
get value by key: 4 is = you

Example 2 : Java Map get Value By Key – Key is not present

Now we will create map and add values in it. In this example we try to get value of key 5 and 10 . because key 5 and 10 is not present in map, So map get method returns null value . Let’s see java get value from map when key is not present .

import java.util.HashMap;
import java.util.Map;

public class HashMapGetValueBykey1 {
   public static void main(String[] args) {
		Map<Integer,String> hm = new HashMap<Integer,String>();

		hm.put(1,"java");
		hm.put(2, "vogue");
		hm.put(3,"welcomes");
		hm.put(4,"you");

		/*
		* Returns the value to which the specified
		* key is mapped, or null if this map contains
		*  no mapping for the key.
		*/

		System.out.println("get value by key: 10 is  = "+hm.get(10));

		System.out.println("get value by key: 5 is = "+hm.get(5));
}
}

Output:

get value by key: 10 is  = null
get value by key: 5 is = null

Example 3 :  Get value Of key in HashMap Using entrySet

We will see how to get value from hashmap in java . In this example we create HashMap using Integer and Sting mapping . We add element in map using put method . We get entrySet from HashMap using entrySet() method.  HashMap entrySet() method return set of Entry . We will iterate this entry set and check key is equal to 3 if key match then print value of key from Entry .

import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

public class HashMapGetValueBykey2 {
	  public static void main(String[] args) {
			Map<Integer,String> hm = new HashMap<Integer,String>();

			hm.put(1,"java");
			hm.put(2, "vogue");
			hm.put(3,"welcomes");
			hm.put(4,"you");
			
			Set<Entry<Integer, String>> entrySet =hm.entrySet();

			for (Entry<Integer, String> entry : entrySet) {
                          if (entry.getKey() == 3) {
		       System.out.println(" value of key 3 is : "+ entry.getValue());
				    }
                          
			}


	}
}

Output:

value of key 3 is : welcomes

In this tutorial we have learned how to get value of key in hashmap . We have given different example of  java get value from map . you can see more java HashMap program for practice .