Spring 에서 Redis 사용하기

✏️ 환경설정

• dependencies

implementation 'org.springframework.boot:spring-boot-starter-data-redis'
implementation 'it.ozimov:embedded-redis:0.7.2'

• application.yml
  • test 파일에도 동일하게 입력해주면 된다.

spring:
  data:
    redis:
      port: 6379
      host: localhost
      password:

✏️ Redis 적용

📍 Embedded redis 적용

• Embedded redis 는 개발 및 테스트를 위해 사용되는 인메모리 형태의 Redis DB 를 뜻한다.
  • 별도의 Redis DB 를 실행시키지 않아도 되기 때문에 어떤 환경에서든 Redis 와 상호작용 할 수 있다.

import io.micrometer.common.util.StringUtils;
import jakarta.annotation.PostConstruct;
import jakarta.annotation.PreDestroy;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Profile;
import redis.embedded.RedisServer;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

@Slf4j
@Profile("!prod")
@Configuration
public class EmbeddedRedisConfig {

    @Value("${spring.data.redis.port}")
    private int redisPort;
    private RedisServer redisServer;

    @PostConstruct
    public void redisServer() throws IOException {
        int port = isRedisRunning() ? findAvailablePort() : redisPort;
        redisServer = RedisServer.builder()
                .port(port)
                .setting("maxmemory 128M")
                .build();
        redisServer.start();
    }

    @PreDestroy
    public void stopRedis() {
        if (redisServer != null)
            redisServer.stop();
    }

    private boolean isRedisRunning() throws IOException {
        return isRunning(executeGrepProcessCommand(redisPort));
    }

    private int findAvailablePort() throws IOException {
        for (int port = 10000; port <= 65535; port++) {
            Process process = executeGrepProcessCommand(port);
            if (!isRunning(process))
                return port;
        }
        throw new IllegalArgumentException("Redis 가 실행할 수 있는 port 가 없음 : 10000 ~ 65535");
    }

    private Process executeGrepProcessCommand(int port) throws IOException {
        String OS = System.getProperty("os.name").toLowerCase();
        if (OS.contains("win")) {
            log.info("OS os {} {}", OS, port);
            String command = String.format("netstat -nao | find \"LISTEN\" | find \"%d\"", port);
            String[] shell = {"cmd.exe", "/y", "/c", command};
            return Runtime.getRuntime().exec(shell);
        }
        String command = String.format("netstat -nat | grep LISTEN|grep %d", port);
        String[] shell = {"/bin/sh", "-c", command};
        return Runtime.getRuntime().exec(shell);
    }

    private boolean isRunning(Process process) {
        String line;
        StringBuilder pidInfo = new StringBuilder();

        try (BufferedReader input = new BufferedReader(new InputStreamReader(process.getInputStream()))) {

            while ((line = input.readLine()) != null)
                pidInfo.append(line);

        } catch (Exception e) {
        }
        return !StringUtils.isEmpty(pidInfo.toString());
    }
}

📍 Redis 적용

• 위 방법은 인메모리 방식으로 Redis 를 실행하는 방법으로 배포 후 실제 운영에서 쓰기엔 무리가 있기 때문에 Redis DB 를 별도로 띄우고 연결하는 방식도 필요하다.

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.RedisPassword;
import org.springframework.data.redis.connection.RedisStandaloneConfiguration;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.serializer.StringRedisSerializer;

@Configuration
public class RedisConfig {

    @Value("${spring.data.redis.host}")
    private String host;

    @Value("${spring.data.redis.port}")
    private int port;

    @Value("${spring.data.redis.password}")
    private String password;

    @Bean
    public RedisConnectionFactory redisConnectionFactory() {
        RedisStandaloneConfiguration config = new RedisStandaloneConfiguration(host, port);
        config.setPassword(RedisPassword.of(password));
        return new LettuceConnectionFactory(config);
    }

    @Bean
    @Primary
    public RedisTemplate<String, String> redisTemplate() {
        RedisTemplate<String, String> redisTemplate = new StringRedisTemplate();
        redisTemplate.setConnectionFactory(redisConnectionFactory());
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setValueSerializer(new StringRedisSerializer());
        return redisTemplate;
    }
}

✏️ Redis util 생성

• 위와 같은 방식으로 Config 객체를 생성하면 Redis 와 연결이 된다.
  • Redis 를 조작하기 위해서 Redis Template 을 사용해 메서드를 만들어주면된다.

import lombok.RequiredArgsConstructor;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;

import static java.util.concurrent.TimeUnit.MILLISECONDS;

@Service
@RequiredArgsConstructor
public class RedisUtil {

    private final RedisTemplate<String, String> redisTemplate;

    public void setData(String key, String value, long timeout) {
        ValueOperations<String, String> valueOperations = redisTemplate.opsForValue();
        valueOperations.set(key, value, timeout, MILLISECONDS);
    }

    public String getValue(String key) {
        ValueOperations<String, String> valueOperations = redisTemplate.opsForValue();
        return valueOperations.get(key);
    }

    public void deleteData(String key) {
        redisTemplate.delete(key);
    }
}