EVCache缓存在 Spring Boot中的实战
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实践一下 EVCache + memcached 缓存如何应用于 Spring Boot应用之中。
文章共 727字,阅读大约需要 2分钟 !
概 述
EVCache 是 Netflix 开源的分布式缓存系统,基于 Memcached缓存和 Spymemcached客户端实现,其用在了大名鼎鼎的 AWS亚马逊云上,并且为云计算做了优化,提供高效的缓存服务。
本文利用 Memcached作为后端缓存实例服务器,并结合 Spring Boot,来实践一下 EVCache客户端的具体使用。
注:本文首发于 My Personal Blog:CodeSheep·程序羊 ,欢迎光临 小站
编译 EVCache
- 第一步:Clone
git clone [email protected]:Netflix/EVCache.git
- 第二步:编译构建
./gradlew build Downloading https://services.gradle.org/distributions/gradle-2.10-bin.zip ................................................................................................................................. ... :evcache-client:check :evcache-client:build :evcache-client-sample:writeLicenseHeader :evcache-client-sample:licenseMain Missing header in: evcache-client-sample/src/main/java/com/netflix/evcache/sample/EVCacheClientSample.java :evcache-client-sample:licenseTest UP-TO-DATE :evcache-client-sample:license :evcache-client-sample:compileTestJava UP-TO-DATE :evcache-client-sample:processTestResources UP-TO-DATE :evcache-client-sample:testClasses UP-TO-DATE :evcache-client-sample:test UP-TO-DATE :evcache-client-sample:check :evcache-client-sample:build BUILD SUCCESSFUL Total time: 22.866 secs
- 第三步:得到构建生成物
同时 ~/EVCache/evcache-client/build/reports
目录下会生成相应构建报告:
接下来我们结合 Spring工程,来实战一下 EVCache Client的具体使用。
环境准备 / 工程搭建
首先准备好两台 memcached实例:
- 192.168.199.77:11211
- 192.168.199.78:11211
接下来搭建一个SpringBoot工程,过程不再赘述,需要注意的一点是 pom中需加入 EVCache的依赖支持
<dependency> <groupId>com.netflix.evcache</groupId> <artifactId>evcache-client</artifactId> <version>4.137.0-SNAPSHOT</version> </dependency>
注:我将 Spring工程设置在 8899端口启动
EVCache Client导入
- 编写 EVCache Client包装类
public class EVCacheClient { private final EVCache evCache; // 关键角色在此 public EVCacheClient() { String deploymentDescriptor = System.getenv("EVC_SAMPLE_DEPLOYMENT"); if ( deploymentDescriptor == null ) { deploymentDescriptor = "SERVERGROUP1=192.168.199.77:11211;SERVERGROUP2=192.168.199.78:11211"; } System.setProperty("EVCACHE_APP1.use.simple.node.list.provider", "true"); System.setProperty("EVCACHE_APP1-NODES", deploymentDescriptor); evCache = new EVCache.Builder().setAppName("EVCACHE_APP1").build(); } public void setKey(String key, String value, int timeToLive) throws Exception { try { Future<Boolean>[] _future = evCache.set(key, value, timeToLive); for (Future<Boolean> f : _future) { boolean didSucceed = f.get(); // System.out.println("per-shard set success code for key " + key + " is " + didSucceed); // 此处可以针对 didSucceed做相应判断 } System.out.println("finished setting key " + key); } catch (EVCacheException e) { e.printStackTrace(); } } public String getKey(String key) { try { String _response = evCache.<String>get(key); return _response; } catch (Exception e) { e.printStackTrace(); return null; } } }
很明显上述类主要提供了两个关键工具函数: setKey
和 getKey
- EVCache Config 配置导入
我们将 EVCacheClient 注入到Spring容器中
@Configuration public class EVCacheConfig { @Bean public EVCacheClient evcacheClient() { EVCacheClient evCacheClient = new EVCacheClient(); return evCacheClient; } }
编写 EVCache Service
上面几步完成之后,Service的编写自然顺理成章,仅仅是一层封装而已
@Service public class EVCacheService { @Autowired private EVCacheClient evCacheClient; public void setKey( String key, String value, int timeToLive ) { try { evCacheClient.setKey( key, value, timeToLive ); } catch (Exception e) { e.printStackTrace(); } } public String getKey( String key ) { return evCacheClient.getKey( key ); } }
编写测试 Controller
我们编写一个方便用于测试的控制器,里面进行一系列对于缓存的 set
和 get
,从而便于观察实验结果
@RestController public class EVCacheTestController { @Autowired private EVCacheService evCacheService; @GetMapping("/testevcache") public void testEvcache() { try { for ( int i = 0; i < 10; i++ ) { String key = "key_" + i; String value = "data_" + i; int ttl = 180; // 此处将缓存设为三分钟(180s)生存期,时间一过,缓存即会失效 evCacheService.setKey(key, value, ttl); } for (int i = 0; i < 10; i++) { String key = "key_" + i; String value = evCacheService.getKey(key); System.out.println("Get of " + key + " returned " + value); } } catch (Exception e) { e.printStackTrace(); } } }
实验验证
工程启动后,我们调用 Rest接口: localhost:8899/testevcache
,观察控制台中对于 key_0
到 key_9
等十个缓存 key的操作细节如下:
- 在 memcached集群中插入十条数据:
key_0
到key_9
注意此处是向每个后端 memcached缓存实例中都写入了 10条测试数据
- 从后端 memcached集群中读取刚插入的 10条数据
- 为了验证数据确实写入到后端 memcached,我们可以 telnet到后端 memcached中进行一一验证
而且这些数据的有效时间仅3分钟,3分钟后再次验证会发现数据已过期
[root@localhost ~]# telnet 127.0.0.1 11211 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. get key_0 VALUE key_0 0 6 data_0 END get key_1 VALUE key_1 0 6 data_1 END get key_2 VALUE key_2 0 6 data_2 END get key_3 VALUE key_3 0 6 data_3 END get key_4 VALUE key_4 0 6 data_4 END get key_5 VALUE key_5 0 6 data_5 END get key_6 VALUE key_6 0 6 data_6 END get key_7 VALUE key_7 0 6 data_7 END get key_8 VALUE key_8 0 6 data_8 END get key_9 VALUE key_9 0 6 data_9 END
本文扩展
当然本文所演示的 EVCache配合 memcached使用时,memcached被硬编码进代码,实际过程中使用,可以将其与 ZK等服务发现服务进行一个结合,实现灵活运用,这就不在本文进行赘述。
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