本文介紹瞭如何使用註解的方式,將Redis快取整合到你的Spring專案。

首先我們將使用jedis驅動，進而開始配置我們的Gradle。

group 'com.gkatzioura.spring'
version '1.0-SNAPSHOT'
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'idea'
apply plugin: 'spring-boot'
buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:1.2.5.RELEASE")
    }
}
jar {
    baseName = 'gs-serving-web-content'
    version =  '0.1.0'
}
sourceCompatibility = 1.8
repositories {
    mavenCentral()
}
dependencies {
    compile "org.springframework.boot:spring-boot-starter-thymeleaf"
    compile 'org.slf4j:slf4j-api:1.6.6'
    compile 'ch.qos.logback:logback-classic:1.0.13'
    compile 'redis.clients:jedis:2.7.0'
    compile 'org.springframework.data:spring-data-redis:1.5.0.RELEASE'
    testCompile group: 'junit', name: 'junit', version: '4.11'
}
task wrapper(type: Wrapper) {
    gradleVersion = '2.3'
}
 

緊接著我們將使用Spring註解，繼續執行Redis裝載配置。

package com.gkatzioura.spring.config;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
@Configuration
@EnableCaching
public class RedisConfig extends CachingConfigurerSupport {
    @Bean
    public JedisConnectionFactory redisConnectionFactory() {
        JedisConnectionFactory jedisConnectionFactory = new JedisConnectionFactory();
        jedisConnectionFactory.setUsePool(true);
        return jedisConnectionFactory;
    }
    @Bean
    public RedisSerializer redisStringSerializer() {
        StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
        return stringRedisSerializer;
    }
    @Bean(name="redisTemplate")
    public RedisTemplate<String, String> redisTemplate(RedisConnectionFactory cf,RedisSerializer redisSerializer) {
        RedisTemplate<String, String> redisTemplate = new RedisTemplate<String, String>();
        redisTemplate.setConnectionFactory(cf);
        redisTemplate.setDefaultSerializer(redisSerializer);
        return redisTemplate;
    }
    @Bean
    public CacheManager cacheManager() {
        return new RedisCacheManager(redisTemplate(redisConnectionFactory(),redisStringSerializer()));
    }
}
 

下一步將建立快取介面CacheService。

package com.gkatzioura.spring.cache;
import java.util.Date;
import java.util.List;
public interface CacheService {
    public void addMessage(String user,String message);
    public List<String> listMessages(String user);
}

當然使用者既可以增加一條訊息也能取回一條訊息。因此，在實現過程中，使用者相關資訊的存在時間將預設設為一分鐘。

我們用Redis來繼承實現CacheService介面。

package com.gkatzioura.spring.cache.impl;
import com.gkatzioura.spring.cache.CacheService;
import org.springframework.data.redis.core.ListOperations;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.SetOperations;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.time.ZonedDateTime;
import java.time.temporal.ChronoUnit;
import java.util.Date;
import java.util.List;
@Service("cacheService")
public class RedisService implements CacheService {
    @Resource(name = "redisTemplate")
    private ListOperations<String, String> messageList;
    @Resource(name = "redisTemplate")
    private RedisOperations<String,String> latestMessageExpiration;
    @Override
    public void addMessage(String user,String message) {
        messageList.leftPush(user,message);
        ZonedDateTime zonedDateTime = ZonedDateTime.now();
        Date date = Date.from(zonedDateTime.plus(1, ChronoUnit.MINUTES).toInstant());
        latestMessageExpiration.expireAt(user,date);
    }
    @Override
    public List<String> listMessages(String user) {
        return messageList.range(user,0,-1);
    }
}

我們的快取機制將保留每個使用者傳送的訊息列表。為了實現這個功能我們將呼叫ListOperations介面，同時將每個user作為一個key鍵值。通過RedisOperations介面，我們可以為key設定特定存在時長。在本例中，主要使用的是 user key。

下一步我們將建立一個controller注入快取服務。

package com.gkatzioura.spring.controller;
import com.gkatzioura.spring.cache.CacheService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
@RestController
public class MessageController {
    @Autowired
    private CacheService cacheService;
    @RequestMapping(value = "/message",method = RequestMethod.GET)
    @ResponseBody
    public List<String> greeting(String user) {
        List<String> messages = cacheService.listMessages(user);
        return messages;
    }
    @RequestMapping(value = "/message",method = RequestMethod.POST)
    @ResponseBody
    public String saveGreeting(String user,String message) {
        cacheService.addMessage(user,message);
        return "OK";
    }
}

最後完成類Application的建立。

package com.gkatzioura.spring;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

經過如上步驟，接下來直接執行Application即可。

原文連結：Integrate Redis into a Spring Project（ 譯者/丘志鵬 審校/朱正貴 責編/仲浩）

譯者簡介：邱志鵬，關注大資料、機器學習。