Lettuce guide (Java) on Docs

Connect to the server

Mon, 01 Jan 0001 00:00:00 +0000

Start by creating a connection to your Redis server. There are many ways to achieve this using Lettuce. Here are a few.

Basic connection

import io.lettuce.core.*;
import io.lettuce.core.api.StatefulRedisConnection;
import io.lettuce.core.api.sync.RedisCommands;

public class ConnectBasicTest {

    public void connectBasic() {
        RedisURI uri = RedisURI.Builder
                .redis("localhost", 6379)
                .withAuthentication("default", "yourPassword")
                .build();
        RedisClient client = RedisClient.create(uri);
        StatefulRedisConnection<String, String> connection = client.connect();
        RedisCommands<String, String> commands = connection.sync();

        commands.set("foo", "bar");
        String result = commands.get("foo");
        System.out.println(result); // >>> bar

        connection.close();

        client.shutdown();
    }
}

Connect to a Redis cluster

To connect to a Redis cluster, use RedisClusterClient.

Connect to Azure Managed Redis

Mon, 01 Jan 0001 00:00:00 +0000

The redis-authx-entraid package lets you authenticate your app to Azure Managed Redis (AMR) using Microsoft Entra ID. You can authenticate using a system-assigned or user-assigned managed identity or a service principal, letting redis-authx-entraid fetch and renew the authentication tokens for you automatically.

See Use Microsoft Entra for cache authentication in the Microsoft docs to learn how to configure Azure to use Entra ID authentication.

Install

Install Lettuce first, if you have not already done so.

Index and query documents

Mon, 01 Jan 0001 00:00:00 +0000

This example shows how to create a search index for JSON documents and run queries against the index. It then goes on to show the slight differences in the equivalent code for hash documents.

Initialize

Make sure that you have Redis Open Source or another Redis server available. Also install the Lettuce client library if you haven't already done so.

Index and query vectors

Mon, 01 Jan 0001 00:00:00 +0000

Redis Query Engine lets you index vector fields in hash or JSON objects (see the Vectors reference page for more information). Among other things, vector fields can store text embeddings, which are AI-generated vector representations of the semantic information in pieces of text. The vector distance between two embeddings indicates how similar they are semantically. By comparing the similarity of an embedding generated from some query text with embeddings stored in hash or JSON fields, Redis can retrieve documents that closely match the query in terms of their meaning.

Vector set embeddings

Mon, 01 Jan 0001 00:00:00 +0000

A Redis vector set lets you store a set of unique keys, each with its own associated vector. You can then retrieve keys from the set according to the similarity between their stored vectors and a query vector that you specify.

You can use vector sets to store any type of numeric vector but they are particularly optimized to work with text embedding vectors (see Redis for AI to learn more about text embeddings). The example below shows how to generate vector embeddings and then store and retrieve them using a vector set with Lettuce.

Production usage

Mon, 01 Jan 0001 00:00:00 +0000

This guide offers recommendations to get the best reliability and performance in your production environment.

Checklist

Each item in the checklist below links to the section for a recommendation. Use the checklist icons to record your progress in implementing the recommendations.