hibernate 二快取 + cluster
原文出自：http://mmmmtodd.blogspot.com/2012/03/hibernate-cluster.html
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result as below我相同 ? true 我是一快取
果示 : from 良格葛 -- 第二次查料，在快取中找到料物件，於是直接返回，第一次查到的料物件是同一例，所以示 true 的果。
那要怎快取清掉呢?
可以透evict()某物件快取中移去，或使用clear()清除快取中的所有物件，
例如 :
public String firstCache() { Users userA = usersService.getById(1L); // session.clear() || session.evict(userA); Users userB = usersService.getById(1L); System.out.println("我相同 ? " + (userA == userB)); System.out.println("我是一快取"); return SUCCESS; }答案就成 false
我相同 ? false 我是一快取
小：取的料很大，每一次 request 就去取一次，造成相的，所以有了二快取西。
就是料有修改，不管次，只要有定二快取，session 就算了以後，二快取如果有的，也不 DB select。
以下始介二快取：
首先，先看一下程式片段：
public String noCache() { Users uA = usersService.getByAccount("markyeh"); System.out.println("我有 快取 : " + uA.getUpdateTime()); return SUCCESS; }然後我了次 http://localhost:8080/Cache/noCache.doresult as below：
Hibernate: /* FROM Users WHERE account = ? */ select users0_.id as id0_, users0_.account as account0_, users0_.address as address0_, users0_.area1 as area4_0_, users0_.area2 as area5_0_, users0_.create_time as create6_0_, users0_.email as email0_, users0_.icon as icon0_, users0_.mobile as mobile0_, users0_.name as name0_, users0_.password as password0_, users0_.reg_ip as reg12_0_, users0_.reg_random_code as reg13_0_, users0_.roc_id as roc14_0_, users0_.score as score0_, users0_.state as state0_, users0_.update_time as update17_0_ from users users0_ where users0_.account=?我有 快取 : 2012-03-15 10:37:41.395Hibernate: /* FROM Users WHERE account = ? */ select users0_.id as id0_, users0_.account as account0_, users0_.address as address0_, users0_.area1 as area4_0_, users0_.area2 as area5_0_, users0_.create_time as create6_0_, users0_.email as email0_, users0_.icon as icon0_, users0_.mobile as mobile0_, users0_.name as name0_, users0_.password as password0_, users0_.reg_ip as reg12_0_, users0_.reg_random_code as reg13_0_, users0_.roc_id as roc14_0_, users0_.score as score0_, users0_.state as state0_, users0_.update_time as update17_0_ from users users0_ where users0_.account=?我有 快取 : 2012-03-15 10:37:41.395行果：hibernate db 行了次的 select，但明明相同的西，怎做才能只 db select 一次就好呢？
就始明如何定 hibernate 的二快取：
我的境如下
struts2 + hibernate + spring + ehcache(第三方作 cache 的套件)
1. 在 spring 定中，在 hibernate 注入的 bean ，增加二快取的定
<bean id="sessionFactory" ref="ihergoSqlDataSource" /> <property name="hibernateProperties"> <props> <!-- <prop key="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</prop> --> <prop key="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</prop> <prop key="hibernate.connection.characterEncoding">utf-8</prop> <prop key="hibernate.show_sql">true</prop> <prop key="hibernate.format_sql">true</prop> <prop key="hibernate.use_sql_comments">true</prop> <prop key="hibernate.cache.use_second_level_cache">true</prop> <!-- 要不要使用二快取 --> <prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</prop> <!-- 指定 EHCache --> <prop key="hibernate.cache.region.factory_class">net.sf.ehcache.hibernate.SingletonEhCacheRegionFactory</prop> <prop key="hibernate.cache.use_query_cache">true</prop> <!-- query 也要快取--> <prop key="hibernate.hbm2ddl.auto">update</prop> </props> </property> <property name="packagesToScan"> <list> <value>mt.buyer.db.entity</value> </list> </property> </bean>2. 定 entity (以 annotation 例)
@Entity@Cache(usage = CacheConcurrencyStrategy.READ_WRITE) // <---, 只定 read_write@Table(name = "users")public class Users implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private long id; /** * */ @Column(name = "account", length = 20, nullable = false) private String account; ...}3. dao // 快取 public Users getByAccountUserCache(final String account) { final String hql = "FROM Users WHERE account = :account "; List memberList = getHibernateTemplate().executeFind( new HibernateCallback>() { public List doInHibernate(Session hbmSs) throws HibernateException, SQLException { // TODO Auto-generated method stub Query query = hbmSs.createQuery(hql); query.setString("account", account); query.setCacheable(true); // <---- return query.list(); } }); if (memberList != null && memberList.size() > 0) { return (Users) memberList.get(0); } return null; } // 有快取 public Users getByAccount(String account) { final String hql = "FROM Users WHERE account = ?"; List memberList = getHibernateTemplate().find(hql, account); if (memberList != null && memberList.size() > 0) { return (Users) memberList.get(0); } return null; }4. 增加定 ehcache.xml 放在 src 下(取入, 也可用 spring 注入) <?xml version="1.0" encoding="UTF-8"?><ehcache><diskStore path="java.io.tmpdir" /><defaultCache maxElementsInMemory="10000" eternal="false"overflowToDisk="true" timeToIdleSeconds="300" timeToLiveSeconds="180"diskPersistent="false" diskExpiryThreadIntervalSeconds="120" /><!-- Hibernate --><cache name="org.hibernate.cache.StandardQueryCache"maxElementsInMemory="5" eternal="false" timeToLiveSeconds="120"overflowToDisk="true"></cache><cache name="org.hibernate.cache.UpdateTimestampsCache"maxElementsInMemory="5000" eternal="true" overflowToDisk="true"></cache></ehcache>5. 程式 (action)
public String cache() { Users uA = usersService.getByAccountUserCache("markyeh"); Users uB = usersService.getByAccountUserCache("markyeh"); System.out.println("快取 : " + uA.getUpdateTime()); System.out.println("快取 : " + uB.getUpdateTime()); return SUCCESS; }6. 行 : http://localhost:8080/Cache/cache.do Hibernate: /* FROM Users WHERE account = :account */ select users0_.id as id0_, users0_.account as account0_, users0_.address as address0_, users0_.area1 as area4_0_, users0_.area2 as area5_0_, users0_.create_time as create6_0_, users0_.email as email0_, users0_.icon as icon0_, users0_.mobile as mobile0_, users0_.name as name0_, users0_.password as password0_, users0_.reg_ip as reg12_0_, users0_.reg_random_code as reg13_0_, users0_.roc_id as roc14_0_, users0_.score as score0_, users0_.state as state0_, users0_.update_time as update17_0_ from users users0_ where users0_.account=?快取 : 2012-03-15 10:37:41.395快取 : 2012-03-15 10:37:41.3957. 可以, 第二次的查就已有再 db search 了, 如果再行相同一次(也就是再一 request 到後台)
快取 : 2012-03-15 10:37:41.395快取 : 2012-03-15 10:37:41.395可以看到，都是二快取的地方取得料，，大家，那修改怎判要不要取得新料 8. 我加入下面的程式：
public String update() { // Users u = usersService.getByAccountUserCache("markyeh"); Users u = usersService.getByAccount("markyeh"); u.setArea1(3); u.setUpdateTime(new Date()); usersService.update(u); System.out.println("我修改了 : " + u.getUpdateTime()); return SUCCESS; }9. 分依序行 3 a) http://localhost:8080/Cache/cache.do b) http://localhost:8080/Cache/update.do c) http://localhost:8080/Cache/cache.do // a) selectHibernate: /* FROM Users WHERE account = :account */ select users0_.id as id0_, users0_.account as account0_, users0_.address as address0_, users0_.area1 as area4_0_, users0_.area2 as area5_0_, users0_.create_time as create6_0_, users0_.email as email0_, users0_.icon as icon0_, users0_.mobile as mobile0_, users0_.name as name0_, users0_.password as password0_, users0_.reg_ip as reg12_0_, users0_.reg_random_code as reg13_0_, users0_.roc_id as roc14_0_, users0_.score as score0_, users0_.state as state0_, users0_.update_time as update17_0_ from users users0_ where users0_.account=?快取 : 2012-03-15 16:39:16.944快取 : 2012-03-15 16:39:16.944第一次行, 果一, 不次// b) updateHibernate: /* FROM Users WHERE account = ? */ select users0_.id as id0_, users0_.account as account0_, users0_.address as address0_, users0_.area1 as area4_0_, users0_.area2 as area5_0_, users0_.create_time as create6_0_, users0_.email as email0_, users0_.icon as icon0_, users0_.mobile as mobile0_, users0_.name as name0_, users0_.password as password0_, users0_.reg_ip as reg12_0_, users0_.reg_random_code as reg13_0_, users0_.roc_id as roc14_0_, users0_.score as score0_, users0_.state as state0_, users0_.update_time as update17_0_ from users users0_ where users0_.account=?Hibernate: /* update mt.buyer.db.entity.Users */ update users set account=?, address=?, area1=?, area2=?, create_time=?, email=?, icon=?, mobile=?, name=?, password=?, reg_ip=?, reg_random_code=?, roc_id=?, score=?, state=?, update_time=? where id=?我修改了 : Thu Mar 15 16:40:19 CST 2012// c) selectHibernate: /* FROM Users WHERE account = :account */ select users0_.id as id0_, users0_.account as account0_, users0_.address as address0_, users0_.area1 as area4_0_, users0_.area2 as area5_0_, users0_.create_time as create6_0_, users0_.email as email0_, users0_.icon as icon0_, users0_.mobile as mobile0_, users0_.name as name0_, users0_.password as password0_, users0_.reg_ip as reg12_0_, users0_.reg_random_code as reg13_0_, users0_.roc_id as roc14_0_, users0_.score as score0_, users0_.state as state0_, users0_.update_time as update17_0_ from users users0_ where users0_.account=?快取 : 2012-03-15 16:40:19.524快取 : 2012-03-15 16:40:19.524可以，ehcache 自判 cache 的西跟 db 的是不是不一了，如果不一再 select 一次放入二快取
小: ehcache.xml 可以定的方式很多，只是 demo，而我也在，官方表示可以做到 tx 的管理，所以是去看一下文件比好。
考文件:
http://www.ehcache.org/documentation/user-guide/hibernate
http://renren.it/a/JAVAbiancheng/Spring/20101022/55282.html
http://caterpillar.onlyfun.net/Gossip/HibernateGossip/SecondLevelCache.html
，因公司架 tomcat cluster ，那...二快取有法共用? 答案是可以的
以下介 cluster 境下怎共用二快取的料：
考了官方文件後，必加入第三方的套件 terracotta 先看看官方的明:
http://terracotta.org/documentation/enterprise-ehcache/get-started
其套件就是一 server ，由 server 你控管各 session
而我的流程大概如下
1. 先 2 tomcat，分定 port 8080, 8081
2. 加入相 jar
3. 修改 ehcache.xml
4. depoly 程式
5. terracotta server run 起
6.
就第二始：
2. ehcache 官有，要做到For Terracotta clustering, download a full Ehcache distribution. 所以先下好案，解，容
相的 lib 加入 ap : ehcache-terracotta-2.5.1.jar terracotta-toolkit-1.4-runtime-4.1.0.jar ... 3. <?xml version="1.0" encoding="UTF-8"?><ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:noNamespaceSchemaLocation="ehcache.xsd" updateCheck="true"monitoring="autodetect"><terracottaConfig url="localhost:9510" /> <!-- 接到 terracotta server 的 ip port --><defaultCache maxElementsInMemory="10000" eternal="false"overflowToDisk="false" timeToIdleSeconds="300" timeToLiveSeconds="180"diskPersistent="false" diskExpiryThreadIntervalSeconds="120" /> <!-- diskPersistent 必成 false --><!-- Hibernate --><cache name="org.hibernate.cache.StandardQueryCache"maxElementsInMemory="5" eternal="false" timeToLiveSeconds="120"overflowToDisk="false"> <!-- overflowToDisk 必成 false --><terracotta /></cache><cache name="org.hibernate.cache.UpdateTimestampsCache"maxElementsInMemory="5000" eternal="true" overflowToDisk="false"> <!-- overflowToDisk 必成 false --><terracotta /></cache></ehcache>5. 在那料, 找到 \ehcache-2.5.1\terracotta\bin\start-tc-server.bat 行, server run 起
6. : 分行 a) http://localhost:8080/Cache/cache.do b) http://localhost:8081/Cache/cache.do 成功...就不了 提供程式下的 https://www.asuswebstorage.com/navigate/share/GYYVXWYN7Y ...
充 :
分散式 cache 考
http://www.informit.com/guides/content.aspx?g=java&seqNum=630
http://bbs.51osos.com/thread-4570-1-1.html
http://terracotta.org/documentation/enterprise-ehcache/configuration-guide
然後多西都有, 如: terracotta 也可以加入 xml 定, 定 port, 而且 terracotta 本身也可以做 cluster
反正看一下官就了