EhCache之初试_JAVA_编程开发_程序员俱乐部

EhCache 是一个纯Java的进程内缓存框架，具有快速、精干等特点，是Hibernate中默认的CacheProvider。

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详情参见其官网站：http://ehcache.org/ ?

具体文件下载网站：http://sourceforge.net/projects/ehcache/files/

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下面将用实际的Demo分类演示介绍EhCache的初步使用：

• 单例CacheManager 创建
• 多个CacheManager 创建
• Cache的多种创建方式
• 对Cache的CRUD的操作
• Cache的统计信息

[一]、单例CacheManager 创建

????? 1.代码示例：

 /**
     * @blog http://sjsky.iteye.com <br>
     *       单例CacheManager 创建
     */
    public static void testCreateSingleton() {
        // Create a singleton CacheManager using defaults
        System.out.println("Create a singleton CacheManager using defaults");
        // CacheManager.create();
        System.out.println("CacheManager.create()     :="
                + CacheManager.getInstance());
        System.out.println("cacheNames length := "
                + CacheManager.getInstance().getCacheNames().length);
        CacheManager.getInstance().shutdown();

        System.out.println("=======================================");

        // Create a singleton CacheManager using a configuration file
        System.out
                .println("Create a singleton CacheManager using a configuration file");
        CacheManager singletonManager2 = CacheManager
                .create("src/main/java/michael/hibernate/cache/ehcache/ehcache.xml");
        System.out.println("CacheManager.create(file) :=" + singletonManager2);
        System.out.println("cacheNames length := "
                + singletonManager2.getCacheNames().length);
        System.out
                .println("CacheManager.getInstance() == singletonManager2 :: "
                        + (CacheManager.getInstance() == singletonManager2));
        singletonManager2.shutdown();
        // CacheManager.getInstance().shutdown();

        System.out.println("=======================================");

        // Create a singleton CacheManager from a configuration resource in the
        // classpath.
        URL configurl = Thread.currentThread().getContextClassLoader()
                .getResource("michael/hibernate/cache/ehcache/ehcache.xml");
        CacheManager singletonManager3 = CacheManager.create(configurl);
        System.out.println("CacheManager.create(url)  :=" + singletonManager3);

        String[] cacheNames = singletonManager3.getCacheNames();
        System.out.println("cacheNames length := " + cacheNames.length);
        for (String name : cacheNames) {
            System.out.println("name := " + name);
        }
        singletonManager3.shutdown();
        // CacheManager.getInstance().shutdown();
    }

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????? 2.运行结果：

Create a singleton CacheManager using defaults
CacheManager.create() :=net.sf.ehcache.CacheManager@e80842
cacheNames length := 4
=======================================
Create a singleton CacheManager using a configuration file
CacheManager.create(file) :=net.sf.ehcache.CacheManager@1bbf1ca
cacheNames length := 6
CacheManager.getInstance() == singletonManager2 :: true
=======================================
CacheManager.create(url) :=net.sf.ehcache.CacheManager@f9c40
cacheNames length := 6
name := sampleRepicatedCache2
name := sampleReplicatedCache1
name := sampleCache2
name := sampleCache1
name := sampleReplicatedCache3
name := sampleCache3

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[二]、多个CacheManager 创建

????? 1.代码示例：

/**
     * @blog http://sjsky.iteye.com <br>
     *       CacheManager 创建
     */
    public static void testCreateManager() {

        // Create a CacheManager instance using defaults
        CacheManager manager1 = new CacheManager();
        System.out.println("new CacheManager()     := " + manager1);
        String[] cacheNames = manager1.getCacheNames();
        System.out.println("cacheNames length := " + cacheNames.length);
        for (String name : cacheNames) {
            System.out.println("name := " + name);
        }
        manager1.shutdown();

        System.out.println("=======================================");

        // Create a CacheManager instance using a configuration file
        CacheManager manager2 = new CacheManager(
                "src/main/java/michael/hibernate/cache/ehcache/ehcache.xml");
        System.out.println("new CacheManager(file) := " + manager2);
        System.out.println("cacheNames length := "
                + manager2.getCacheNames().length);
        manager2.shutdown();

        System.out.println("=======================================");
        // Create a singleton CacheManager from a configuration resource in the
        // classpath.
        URL configurl = Thread.currentThread().getContextClassLoader()
                .getResource("michael/hibernate/cache/ehcache/ehcache.xml");
        CacheManager manager3 = new CacheManager(configurl);
        System.out.println("new CacheManager(url)  := " + manager3);
        System.out.println("cacheNames length := "
                + manager3.getCacheNames().length);
        for (String name : manager3.getCacheNames()) {
            System.out.println("name := " + name);
        }
        manager3.shutdown();

    }

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????? 2.运行结果：

new CacheManager() := net.sf.ehcache.CacheManager@17653ae
cacheNames length := 4
name := sampleCache2
name := org.hibernate.cache.UpdateTimestampsCache
name := sampleCache1
name := org.hibernate.cache.StandardQueryCache
=======================================
new CacheManager(file) := net.sf.ehcache.CacheManager@1ff0dde
cacheNames length := 6
=======================================
new CacheManager(url) := net.sf.ehcache.CacheManager@db4fa2
cacheNames length := 6
name := sampleRepicatedCache2
name := sampleReplicatedCache1
name := sampleCache2
name := sampleCache1
name := sampleReplicatedCache3
name := sampleCache3 ?

[三]、Cache的多种创建方式

????? 1.代码示例：?

    /**
     * @blog http://sjsky.iteye.com <br>
     *       Create Cache
     */
    public static void testCreateCache() {

        System.out.println("add cache with defaults:");
        CacheManager singletonManager = CacheManager.create();
        singletonManager.addCache("myCache1");
        Cache myCache1 = singletonManager.getCache("myCache1");
        System.out.println(myCache1);

        System.out.println("add cache with new Cache(arg1,arg2...):");
        Cache myMemoryCache = new Cache("myMemoryCache", 5000, false, false, 5,
                2);
        singletonManager.addCache(myMemoryCache);
        System.out.println(singletonManager.getCache("myMemoryCache"));

        System.out.println("Create a Cache specifying its configuration:");
        // Create a Cache specifying its configuration.
        int maxElements = 100;
        Cache myConfigCahce = new Cache(new CacheConfiguration("myConifgCahce",
                maxElements).memoryStoreEvictionPolicy(
                MemoryStoreEvictionPolicy.LFU).overflowToDisk(true).eternal(
                false).timeToLiveSeconds(60).timeToIdleSeconds(30)
                .diskPersistent(false).diskExpiryThreadIntervalSeconds(0));
        singletonManager.addCache(myConfigCahce);
        System.out.println(singletonManager.getCache("myConifgCahce"));

        singletonManager.shutdown();

    }

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????? 2.运行结果：

add cache with defaults:
[ name = myCache1 status = STATUS_ALIVE eternal = false overflowToDisk = true maxElementsInMemory = 100 maxElementsOnDisk = 100 memoryStoreEvictionPolicy = LRU timeToLiveSeconds = 120 timeToIdleSeconds = 120 diskPersistent = false diskExpiryThreadIntervalSeconds = 120 cacheEventListeners: net.sf.ehcache.statistics.LiveCacheStatisticsWrapper hitCount = 0 memoryStoreHitCount = 0 diskStoreHitCount = 0 missCountNotFound = 0 missCountExpired = 0 overflowToOffHeap = false maxMemoryOffHeap = null ]
add cache with new Cache(arg1,arg2...):
[ name = myMemoryCache status = STATUS_ALIVE eternal = false overflowToDisk = false maxElementsInMemory = 5000 maxElementsOnDisk = 0 memoryStoreEvictionPolicy = LRU timeToLiveSeconds = 5 timeToIdleSeconds = 2 diskPersistent = false diskExpiryThreadIntervalSeconds = 120 cacheEventListeners: net.sf.ehcache.statistics.LiveCacheStatisticsWrapper hitCount = 0 memoryStoreHitCount = 0 diskStoreHitCount = 0 missCountNotFound = 0 missCountExpired = 0 overflowToOffHeap = false maxMemoryOffHeap = null ]
Create a Cache specifying its configuration:
[ name = myConifgCahce status = STATUS_ALIVE eternal = false overflowToDisk = true maxElementsInMemory = 100 maxElementsOnDisk = 0 memoryStoreEvictionPolicy = LFU timeToLiveSeconds = 60 timeToIdleSeconds = 30 diskPersistent = false diskExpiryThreadIntervalSeconds = 120 cacheEventListeners: net.sf.ehcache.statistics.LiveCacheStatisticsWrapper hitCount = 0 memoryStoreHitCount = 0 diskStoreHitCount = 0 missCountNotFound = 0 missCountExpired = 0 overflowToOffHeap = false maxMemoryOffHeap = null ]
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[四]、对Cache的CRUD的操作

????? 1.代码示例：

   /**
     * @blog http://sjsky.iteye.com <br>
     *       CRUD operations
     */
    public static void testCacheElementCRUD() {
        CacheManager manager = null;
        try {
            manager = new CacheManager();
            manager.addCache("MichaelInfo");

            Cache myCache = manager.getCache("MichaelInfo");
            System.out.println("manager.getCache :" + myCache);

            Element element = new Element("blog", "http://sjsky.javaeye.com");
            myCache.put(element);
            System.out.println("cache put Element");
            System.out.println("get Element value:= "
                    + myCache.get("blog").getValue());
            System.out.println("get Element objectvalue:= "
                    + myCache.get("blog").getObjectValue());

            System.out.println("update the Element");
            myCache.put(new Element("blog", "http://sjsky.iteye.com"));
            System.out.println("get Element value:= "
                    + myCache.get("blog").getValue());
            System.out.println("get Element objectvalue:= "
                    + myCache.get("blog").getObjectValue());

            myCache.put(new Element("array", new String[] { "test", "array" }));
            System.out.println("array value:= "
                    + myCache.get("array").getValue());
            myCache.remove("array");
            if (null == myCache.get("array")) {
                System.out.println("remove Element 'array' successful.");
            }
        } catch (Exception e) {
            e.printStackTrace(System.out);
        } finally {
            if (null != manager) {
                manager.shutdown();
            }
        }
    }

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????? 2.运行结果：

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manager.getCache :[ name = MichaelInfo status = STATUS_ALIVE eternal = false overflowToDisk = true maxElementsInMemory = 100 maxElementsOnDisk = 100 memoryStoreEvictionPolicy = LRU timeToLiveSeconds = 120 timeToIdleSeconds = 120 diskPersistent = false diskExpiryThreadIntervalSeconds = 120 cacheEventListeners: net.sf.ehcache.statistics.LiveCacheStatisticsWrapper hitCount = 0 memoryStoreHitCount = 0 diskStoreHitCount = 0 missCountNotFound = 0 missCountExpired = 0 overflowToOffHeap = false maxMemoryOffHeap = null ]
cache put Element
get Element value:= http://sjsky.javaeye.com
get Element objectvalue:= http://sjsky.javaeye.com
update the Element
get Element value:= http://sjsky.iteye.com
get Element objectvalue:= http://sjsky.iteye.com
array value:= [Ljava.lang.String;@ec4a87
remove Element 'array' successful. ?

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[五]、Cache的统计信息

????? 1.代码示例：

    /**
     * @blog http://sjsky.iteye.com <br>
     *       cache 信息统计
     */
    public static void testCacheStatistics() {
        CacheManager manager = null;
        try {
            manager = new CacheManager();
            manager.addCache("MichaelInfo");

            Cache myCache = manager.getCache("MichaelInfo");

            myCache.put(new Element("username", "Michael"));
            myCache.put(new Element("sex", "男"));
            myCache.put(new Element("date", new Date()));
            myCache.put(new Element("height", 172));
            myCache.put(new Element("position", "cto"));
            myCache.put(new Element("blog", "http://sjsky.iteye.com"));

            System.out.println("cache size := " + myCache.getSize());
            System.out.println("MemoryStoreSize := "
                    + myCache.getMemoryStoreSize());
            System.out
                    .println("DiskStoreSize := " + myCache.getDiskStoreSize());

            myCache.getStatistics().getDiskStoreObjectCount();
            System.out.println("Caceh getStatistics:");
            Statistics statistics = myCache.getStatistics();
            System.out.println("CacheHits := " + statistics.getCacheHits());
            System.out.println("CacheMisses := " + statistics.getCacheMisses());
            System.out.println("InMemoryHits := "
                    + statistics.getInMemoryHits());
            System.out.println("InMemoryMisses := "
                    + statistics.getInMemoryMisses());
            System.out.println("OnDiskHits := " + statistics.getOnDiskHits());
            System.out.println("OnDiskMisses := "
                    + statistics.getOnDiskMisses());
            System.out.println("MemoryStoreObjectCount := "
                    + statistics.getMemoryStoreObjectCount());
            System.out.println("DiskStoreObjectCount := "
                    + statistics.getDiskStoreObjectCount());

            Element element = myCache.get("username");
            System.out.println("Element HitCount := " + element.getHitCount());

        } catch (Exception e) {
            e.printStackTrace(System.out);
        } finally {
            if (null != manager) {
                manager.shutdown();
            }
        }
    }

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????? 2.运行结果：

cache size := 6
MemoryStoreSize := 6
DiskStoreSize := 0
Caceh getStatistics:
CacheHits := 0
CacheMisses := 0
InMemoryHits := 0
InMemoryMisses := 0
OnDiskHits := 0
OnDiskMisses := 0
MemoryStoreObjectCount := 6
DiskStoreObjectCount := 0
Element HitCount := 1

?这次初步的简单使用就讲到这，下面一节讲EhCache和Hibernate的集成应用。

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本文连接：http://sjsky.iteye.com/blog/1288257

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转载请注明来自：Michael's blog @ http://sjsky.iteye.com

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