How to add hashmap into redis?
How to add hashmap into redis?
1 answer
by
darrion.kuhn ,
5 months ago
@domenico
You cannot directly add a Java HashMap object into Redis, as Redis is a key-value store that only accepts string values. However, you can serialize the HashMap object into a JSON string and then store it in Redis using a specific key.
Here is an example of how you can add a HashMap into Redis using Jedis, a popular Java client for Redis:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 |
import redis.clients.jedis.Jedis;
import com.google.gson.Gson;
import java.util.HashMap;
public class RedisExample {
public static void main(String[] args) {
Jedis jedis = new Jedis("localhost");
// Create a HashMap
HashMap<String, String> map = new HashMap<>();
map.put("key1", "value1");
map.put("key2", "value2");
// Serialize the HashMap into a JSON string
Gson gson = new Gson();
String json = gson.toJson(map);
// Store the JSON string in Redis
jedis.set("myHashMap", json);
// Retrieve the HashMap from Redis
String jsonFromRedis = jedis.get("myHashMap");
HashMap<String, String> mapFromRedis = gson.fromJson(jsonFromRedis, HashMap.class);
// Print the HashMap retrieved from Redis
System.out.println(mapFromRedis);
jedis.close();
}
}
|
In this example, we first create a HashMap object and serialize it into a JSON string using the Gson library. Next, we store this JSON string in Redis with the key "myHashMap". Finally, we retrieve the JSON string from Redis, deserialize it back into a HashMap object, and print it out.