JbossCache使用

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附录：

1 在实际工作中的应用

看了上面的说明，是不是对Jboss Cache有了一定的了解了哪？

在数据库缓存的实际应用中，Jboss Cache一般用来缓存两种类型的数据，一种是频繁变化的数据，比如说证券业的行情，1秒钟更新一次，要读取N多次，放到数据库中根本不可行。

一种是不太变化的数据，比说如用户，组织，权限的数据，不会经常变化，但是会经常check用户的权限，这类表也适合放入到缓存中保存。

2 JbossCache的用法

1 下载JbossCache的包

2 配置JbossCache.xml文件，例子如下：

<?xmlversion="1.0"encoding="UTF-8"?>

<jbosscachexmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns="urn:jboss:jbosscache-core:config:3.0">

<!--

isolation levels supported: READ_COMMITTED and REPEATABLE_READ

nodeLockingSchemes: mvcc, pessimistic (deprecated), optimistic (deprecated)

-->

<locking

isolationLevel="REPEATABLE_READ"

lockParentForChildInsertRemove="false"

lockAcquisitionTimeout="20000"

nodeLockingScheme="mvcc"

writeSkewCheck="false"

concurrencyLevel="500"/>

<!--

Used to register a transaction manager and participate in ongoing transactions.

-->

<!-- <transaction

transactionManagerLookupClass="org.jboss.cache.transaction.GenericTransactionManagerLookup"

syncRollbackPhase="false"

syncCommitPhase="false"/>

-->

<!--

Used to register JMX statistics in any available MBean server

-->

<jmxStatistics

enabled="false"/>

<!--

If region based marshalling is used, defines whether new regions are inactive on startup.

-->

<startup

regionsInactiveOnStartup="true"/>

<!--

Used to register JVM shutdown hooks.

hookBehavior: DEFAULT, REGISTER, DONT_REGISTER

-->

<shutdown

hookBehavior="DEFAULT"/>

<!--

Used to define async listener notification thread pool size

-->

<listeners

asyncPoolSize="1"

asyncQueueSize="1000000"/>

<!--

Used to enable invocation batching and allow the use of Cache.startBatch()/endBatch() methods.

-->

<invocationBatching

enabled="true"/>

</jbosscache>

3 在启动时加载JbossCache，可以放到Listener中启动，示例程序如下：

/**

*loadtheConsttabletomemorywhenappserverstart

privatevoid initConstTableToMemory() {

// init the jboss cache

CacheFactory factory =new DefaultCacheFactory();

Cache cache = factory.createCache("JBossCache.xml");

cache.create();

cache.start();

WebContextHolder.getInstence().setJbossCache(cache);

RefreshConstToMemory memory =new RefreshConstToMemory();

memory. refreshPdmmthdToMemory ();

}

4 RefreshConstToMemory是存放Jboss Cache数据的例子：

publicvoidrefreshPdmmthdToMemory() {

Cache cache = WebContextHolder.getInstence().getJbossCache();

Node rootNode = cache.getRoot();

Node node = null;

Fqn fqn = null;

//从数据库中取出pdmmthd表的内容，放到Jboss Cache中。

PdmmthdDAO pdmmthdDAO = (PdmmthdDAO) BeanUtil.getBean("pdmmthdDAO");

List<Pdmmthd> pdmmthdList = pdmmthdDAO.getAllMethodFromDatabase();

node = cache.getNode("/pdmmthd");

if (node ==null) {

fqn = Fqn.fromString("/pdmmthd");

node = rootNode.addChild(fqn);

}

node.put("/pdmmthd", pdmmthdList);

for (Pdmmthd pdmmthd : pdmmthdList) {

node.put(pdmmthd.getMtcode(), pdmmthd);

}

在数据库第一次启动，在数据更新以后，都需要手工调用上述的refreshALLMemory()方法。

为了保险起见，对于不支持Jboss Cache的情况，或者Jboss Cache出现故障，我们可以在查询时增加出错处理，示例程序如下：

public List<Pdmmthd> getAllMethodFromMemory() {

// try the Exception in case of can't find 'method' in memory

try {

Cache cache = WebContextHolder.getInstence().getJbossCache();

Node node = cache.getNode("/pdmmthd");

List list = (List) node.get("/pdmmthd");

// return a new List,cause the user need change the list.

// For example,It will add "All" method to the list.

List dest = new ArrayList();

dest.addAll(list);

returndest;

} catch (Exception e) {

return getAllMethodFromDatabase();

}

转自：http://blog.csdn.net/hobbypei/article/details/4417825

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