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 ...");
} }