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Ehcache Demo
转自:
https://my.oschina.net/zb0423/blog/60957
http://www.cnblogs.com/fsjin/articles/3521261.html
Ehcache 是现在最流行的纯Java开源缓存框架,配置简单、结构清晰、功能强大。
- 下载jar包 ehcache-core-2.3.0.jar
- maven 仓库代理 https://repository.jboss.org/nexus/content/groups/developer/
- 新搭建一个Maven项目
- 配置jar包到pom文件中
- 编写ehcache.xml缓冲配置文件 可以放在src的任何目录下
pom文件:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.lzyan.ehcache.demo</groupId> <artifactId>EhcacheDemo</artifactId> <version>v0.1</version> <name>EhcacheDemo</name> <dependencies> <dependency> <groupId>net.sf.ehcache</groupId> <artifactId>ehcache-core</artifactId> <version>2.6.6</version> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.14</version> <scope>compile</scope> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.6.6</version> </dependency> </dependencies> </project>
ehcache.xml文件:
<ehcache updateCheck="false" dynamicConfig="false"> <!-- Sets the path to the directory where cache .data files are created. If the path is a Java System Property it is replaced by its value in the running VM. The following properties are translated: user.home - User‘s home directory user.dir - User‘s current working directory java.io.tmpdir - Default temp file path --> <diskStore path="D:/tmp/test/ehcache"/> <cacheManagerEventListenerFactory class="" properties=""/> <!--Default Cache configuration. These will applied to caches programmatically created through the CacheManager. The following attributes are required for defaultCache: maxInMemory - Sets the maximum number of objects that will be created in memory eternal - Sets whether elements are eternal. If eternal, timeouts are ignored and the element is never expired. timeToIdleSeconds - Sets the time to idle for an element before it expires. Is only used if the element is not eternal. Idle time is now - last accessed time timeToLiveSeconds - Sets the time to live for an element before it expires. Is only used if the element is not eternal. TTL is now - creation time overflowToDisk - Sets whether elements can overflow to disk when the in-memory cache has reached the maxInMemory limit. --> <defaultCache maxElementsInMemory="1000" eternal="false" timeToIdleSeconds="1200000" timeToLiveSeconds="1200000" overflowToDisk="true" /> <cache name="icache-global" maxElementsInMemory="1000" eternal="true" timeToIdleSeconds="1800" timeToLiveSeconds="1800" overflowToDisk="true" /> <cache name="SimplePageCachingFilter" maxElementsInMemory="10000" maxElementsOnDisk="1000" eternal="false" overflowToDisk="true" timeToIdleSeconds="300" timeToLiveSeconds="600" memoryStoreEvictionPolicy="LFU" /> </ehcache>
编写测试类:
import java.net.URL; import java.util.concurrent.TimeUnit; import net.sf.ehcache.Cache; import net.sf.ehcache.CacheManager; import net.sf.ehcache.Element; public class EhCache_v2 { public static void main(String[] args) throws Exception { System.out.println("main(): begin ..."); ClassLoader loader = Thread.currentThread().getContextClassLoader(); URL url = loader.getResource("ehcache.xml"); //创建一个缓存管理器 CacheManager manager = CacheManager.create(url); String names[] = manager.getCacheNames(); System.out.println("Available caches list: \n---------"); for (int i = 0; i < names.length; i++) { System.out.println(names[i]); } System.out.println("---------"); if(names.length > 0){ System.out.println("Selected_CacheName=" + names[0]); } Cache cache = manager.getCache(names[0]); cache.put(new Element("name", "admin")); Element element = cache.get("name"); System.out.println("getValue()=" + element.getValue()); Object obj = element.getObjectValue(); System.out.println("getObjectValue()=" + obj); TimeUnit.SECONDS.sleep(3); ThreadAction action = new ThreadAction(); action.setCacheName(cache.getName()); action.setManager(manager); action.start(); System.out.println("=== main thread is return! ==="); } } class ThreadAction extends Thread{ private String cacheName; private CacheManager manager ; @Override public void run() { try { Thread.sleep(3000); Cache cache = manager.getCache(cacheName); Element element = cache.get("name"); System.out.println("run(): 从缓存中取得数据:" + element.getObjectValue()); } catch (InterruptedException e) { e.printStackTrace(); } } public CacheManager getManager() { return manager; } public void setManager(CacheManager manager) { this.manager = manager; } public String getCacheName() { return cacheName; } public void setCacheName(String cacheName) { this.cacheName = cacheName; } }
测试出缓存起作用:
需要设置配置文件中缓存名 name="SimplePageCachingFilter" 的存活时间
eternal="false" timeToIdleSeconds="1" timeToLiveSeconds="1"
不知道什么缓存管理器读取配置文件的规则,取出的 name[0] 是文件最后一个配置的缓存
然后再试运行 发现抛出空指针异常,说明从缓存中取不到数据了,说明这个测试可以测试出缓存是否起作用。
Demo2:
import net.sf.ehcache.Cache; import net.sf.ehcache.CacheManager; import net.sf.ehcache.Element; public class EhCache { public static void main(String[] args) { System.out.println("main(): begin ..."); // CacheManager manager = new CacheManager(); //创建一个缓存管理器 CacheManager singletonManager = CacheManager.create(); //建立一个缓存实例 Cache memoryOnlyCache = new Cache("testCache", 5000, false, false, 5, 2); //在内存管理器中添加缓存实例 singletonManager.addCache(memoryOnlyCache); Cache cache = singletonManager.getCache("testCache"); //使用缓存 Element element = new Element("key1", "value1"); cache.put(element); cache.put(new Element("key1", "value2")); element = cache.get("key1"); Object value = element.getObjectValue(); System.out.println(value); int elementsInMemory = cache.getSize(); System.out.println(elementsInMemory); long elementsInMemory2 = cache.getMemoryStoreSize(); System.out.println(elementsInMemory2); Object obj = element.getObjectValue(); cache.remove("key1"); System.out.println(obj); singletonManager.shutdown(); // manager.shutdown(); System.out.println("main(): over ..."); } }
Ehcache Demo
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