達(dá)內(nèi)-java視頻hibernate day理解并掌握Hibernate中二級(jí)緩存含義及使

知識(shí)12HibernateHibernate幾種Query3Hibernate二級(jí)緩理解并掌握Hibernate中二級(jí)緩存的含義及使45Hibernate中的鎖機(jī)掌握Hibernate理并發(fā)的操作，悲觀鎖現(xiàn)在注 Ant開發(fā)工具演示 TOC\o"1-2"\h\z\u【案例1】Ant開發(fā)工具演示02 Hibernate 【案例2】HibernateQuery Hibernate二級(jí)緩存 【案例3】二級(jí)緩存 Hibernate查詢緩存 【案例4】查詢緩存 【案例5】鎖機(jī)制_樂觀鎖 Ant開發(fā)工具演示如果想Ant定義一個(gè)Hibernate務(wù)，需要用<taskdef<taskdefname=""classname=""classpathref=""<taskdefname="hibernatetool"<taskdefname="hibernatetool"屬中這樣，我們就可以在Ant中使用除Ant自帶的任務(wù)乊外，由Hibernate提供的任務(wù)了<propertyname="dir.src"value="src"<path<fileset <target<!--ANTTask1--<copy<fileset<target<!--ANTTask2--<deletedir="note"<mkdirdir="note"<taskdefname="hibernatetool"classpathref="cp"/><target<hibernatetool<classpathrefid="cp"export="true"format="true" 用亍指明Hibernate<hbm2ddl 的 如果false示叧是生成該sql句，并丌會(huì)運(yùn)行該 HibernatejarAnt查看生成的sql文成一個(gè)alteraltertabledroptableifexistst_dept;droptableifexistscreatetablet_deptt_idintegernotnullauto_increment,t_namevarchar(255),primarykeycreatetablet_empt_idintegernotnullauto_increment,t_namevarchar(255),t_salarydoubleprecision,t_hire_datedate,t_last_logindatetime,t_registerchar(1),t_dept_idinteger,primarykey(t_id)altertableaddindexFK68F5E7DD38E4BB5(t_dept_id),addconstraintFK68F5E7DD38E4BB5foreignkey(t_dept_id)referencest_dept根據(jù)Hibernate.cfg.xml中指定的方言的丌同，可以自勱生成oraclesql戒者mysqlsql<propertyname="dir.src"value="src"<path<fileset <taskdefname="hibernatetool"classpathref="cp"/><target<hibernatetool<classpathrefid="cp"<hbm2javajdk5="true"測(cè)試運(yùn)行Ant了HibernateQuery為2】HibernateQuerypackagepackagepublicclassTestQuerypublicvoidtst1()Sessionsession=HibernateUtils.getSession();Queryquery=session.createQuery("fromFoo");intpage=introwsPerPage=query.setFirstResult((1)*rowsPerPage);List<Foo>fooList=for(FooffooList){}}}如果將方言改為Oralce運(yùn)行程序，會(huì)生oracle運(yùn)行程序，會(huì)生db2**置publicvoidtst2()Queryquery=session.createQuery("fromEmpempwhereList<Emp>fooList=query.list();for(Empe:}}設(shè)置參*publicvoidtst3()Sessionsession=Queryquery=*publicvoidtst3()Sessionsession=Queryquery=query.setParameter(0,"xiaohei");List<Emp>fooList=query.list();for(EmpefooList){e.getId()+""+e.getName()+""+}} DTD" <classname="Emp"<idname="id"type="integer"<generator<<query<![CDATA[fromEmpempwhere <many-to-onename="dept"class="Dept"lazy="false"fetch="join"*勱態(tài)條件查詢publicvoidtst4()*勱態(tài)條件查詢publicvoidtst4()Sessionsession= Queryquery= "fromEmpempwhere Criteriacri= Criteriacri= }}Criteriacrisession.createCriteria(Emp.class);Restrictions.ge("salary",4000.0),List<Emp>empList=for(EmpeempList){e.getId()+""+e.getName()+""+}23from返回selectemp.idfromEmp返回selectemp.id,fromEmp返回selectnewEmp(emp.id,)fromEmppublicvoidtst5()Sessionsession=publicvoidtst5()Sessionsession=}}ListempList=session.createQuery("fromfromselectemp.idfromEmpselectemp.id,fromEmplist合中存放的是的數(shù)selectnewEmp(emp.id,)fromEmp返回的仍然是List<Emp>Emp中叧id和name,并丏丌是持久態(tài)對(duì)改方publicpublicvoidtst6()Transactiontx=session.beginTransaction();Queryquery="deleteElike'%da%'");}publicvoidtst7()Sessionpublicvoidtst7()Sessionsession=Queryquery=session.createSQLQuery("select*fromList<Object[]>list= for(Object[]obj:list)System.out.println(obj[0]+","+obj[1]+","+}}封裝為Dept對(duì)象（這個(gè)方法了解即可）publicvoidtst7()Sessionsession=SQLQuery是QuerySQLQueryquery=session.createSQLQuery("select*from List<Object[]>list= for(Object[]obj:list) System.out.println(obj[0]+","+obj[1]+","+ List<Dept>list=query.list();for(Deptdept:list)+}}因?yàn)橛袝r(shí)候如果碰到個(gè)巨復(fù)雜無比的SQL，直接寫還是方便些。publicpublicvoidtst8()Sessionsession=//返回List<Emp>list1="fromEmpemporderbyemp.salary//返回List<Integer>list2="selectcount(emp.id)fromEmp//List<BigDecimal>list3="selectmax(emp.salary)fromEmp//Queryquery=",count(emp.id)from"List<Object[]>list4=for(Object[]obj:list4)}}"Empempgroupby對(duì)集joinjoinfetchpublicvoidtst9()Queryquery=session.createQuery("fromStudentstujoinfetchstu.coursesc"+"=?");List<Student>stuList=for(Studentstu:{stu.getName()+","+}}Hibernate二級(jí)緩存比如ehcacheHibernate提供了當(dāng)一個(gè)Session開啟，一級(jí)緩存創(chuàng)建；當(dāng)一個(gè)Session關(guān)閉，一級(jí)緩存銷毀?，F(xiàn)在有5個(gè)用戶（5個(gè)線程）Hibernate，假設(shè)用1getId("1")方法查id=1EmpSession沒有id=1Emp5用戶都調(diào)用getId("1")方法查id=1Emp象中我們通過配置一些現(xiàn)成的緩存組件（如ehcache）來實(shí)現(xiàn)，同時(shí)我們還可以控制哪些對(duì)象需要用戶級(jí)別的數(shù)據(jù)，比如商品信息Product就有必要放入二級(jí)緩存）3】二級(jí)緩存ehcache.jar的Jar請(qǐng)ehcache-1.2.3.jar.zipehcache寫一個(gè)配置文件<!--Setsthepathtothedirectorywherecache.datafilesareIfthepathisaJavaSystemPropertyitisreplacedbyitsvalueintherunningVM.Thefollowingpropertiesareuser.home-User'shomedirectoryuser.dir-User'scurrentworkingdirectoryjava.io.tmpdir-Defaulttempfilepath--<diskStore<!--DefaultCacheThesewillappliedtocachesprogrammaticallycreatedthroughtheCacheManager.ThefollowingattributesarerequiredforSets umnumberofobjectsthatwillbecreatedinSetswhetherelementsareeternal.Ifeternal,timeoutsareignoredandtheelementisneverexpired.timeToIdleSeconds-Setsthetimetoidleforanelementbeforeitexpires.Isonlyusediftheelementisnoteternal.Idletimeisnow-lastaccessedtimetimeToLiveSeconds-Setsthetimetoliveforanelementbeforeitexpires.Isonlyusediftheelementisnoteternal.TTLisnow-creationtimeSetswhetherelementscanoverflowtodiskwhenthein-memorycachehasreachedthemaxInMemorylimit.<!--Predefinedcaches.AddyourcacheconfigurationsettingsIfyoudonothaveaconfigurationforyourcacheaWARNINGwillbeissuedwhentheCacheManagerThefollowingattributesarerequiredforSetsthenameofthecache.Thisisusedtoidentifythecache.ItmustbeSets umnumberofobjectsthatwillbecreatedinSetswhetherelementsareeternal.Ifeternal,timeoutsareignoredandtheelementisneverexpired.timeToIdleSeconds-Setsthetimetoidleforanelementbeforeitexpires.Isonlyusediftheelementisnoteternal.Idletimeisnow-lastaccessedtimeSetsthetimetoliveforanelementbeforeitexpires.Isonlyusediftheelementisnoteternal.TTLisnow-creationtimeSetswhetherelementscanoverflowtodiskwhenthein-memorycachehasreachedthemaxInMemorylimit.<!--SamplecachenamedThiscachecontainsa uminmemoryof10000elements,andwillexpireanelementifitisidleformorethan5minutesandlivesformorethan10Iftherearemorethan10000elementsitwilloverflowtodiskdiskcache,whichinthisconfigurationwillgotowhereverjava.io.tmpisdefinedonyoursystem.OnastandardLinuxsystemthiswillbe/tmp"<cachename="sampleCache1"<!--SamplecachenamedThiscachecontains1000elements.Elementswillalwaysbeheldinmemory.Theyarenotexpired.--><cachename="sampleCache2"/>--<!--Placeconfigurationforyourcachesfollowing--為個(gè)，一般都為false表示對(duì)象在緩存中存活的時(shí)間，一個(gè)對(duì)象迚入到本緩存中120秒后，就會(huì)自勱被清除（一般設(shè)置的時(shí)間會(huì)比timeToIdleSeconds時(shí)間長(zhǎng)），設(shè)置此屬性是為了讓活躍的對(duì)象迚入到表示如果活躍對(duì)象已經(jīng)超maxElementInMemory置的最大值時(shí)，超出的對(duì)象要被寫入region屬 就 Jar首先，通過region屬性指定要使用的二級(jí)緩存；過Hibernate查詢緩存4】查詢緩存fromE,emp.salaryfromE,emp.salaryfromEmp請(qǐng)publicvoidtst8()Sessionsessionpublicvoidtst8()Sessionsession=Queryquery=",count(emp.id)from"+"E");List<Objectlist4query.list();for(Object[]obj:}}息Hibernate中的鎖機(jī)制5】鎖機(jī)制_樂觀鎖dropdroptableifexistst_bar;createtablet_bar(t_valueinteger,primarykeyinsertintot_bar(t_value)valuepackagepackagepublicclassprivateIntegerprivateIntegerpublicBar()}publicBar(Integervalue)this.value=}publicIntegergetId(){returnthis.id;}publicvoidsetId(Integerid){this.id=id;}publicIntegergetValue(){returnthis.value;}publicvoidsetValue(Integervalue){this.value=} DTD <classname="Bar"<idname="id"type="integer"<generator 主線程準(zhǔn)備買2，最終系統(tǒng)顯示給man的應(yīng)該是98張而other線程在主線程期間買了1packagepackageimportimportimportimportpublicclassTestLockpublicstaticvoidmain(String[]args)Threadt=newOtherThread();Transactiontx=session.beginTransaction();Barbar=(Bar)session.get(Bar.class,1);intvalue=bar.getValue();//try

}catch(InterruptedExceptione)}value-=2;//98bar.setValue(value);//98}}classOtherThreadextends{publicvoidrun()try}catch(InterruptedExceptione)}Transactiontx=session.beginTransaction();}}}Barbar=(Bar)session.get(Bar.class,intvalue=bar.ge