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Posted on 2007-11-12 16:29 G_G 閱讀(2076) 評(píng)論(3) 編輯 收藏 所屬分類: hibernate
緩存問題：
????
/**
?使用?Query.executeUpdate()?緩存中數(shù)據(jù)不同步?解決辦法
?????*??Table?->?T1oo(id,name)
?????*?Table?->?T2oo(id,avg,aid)
?????*?外鍵?T1oo.id->T2oo.aid
?????*??Session.createQuery("delete?T1oo")?->??Query.executeUpdate()?
????
*/
????
public
?
void
?testExecuteUpdate(){
????????System.out.println(
"
\r\n\r\n********************ExecuteUpdate************************
"
);
????????T1oo?t1oo?
=
?
new
?T1oo();
????????t1oo.setName(
"
liukaiyi
"
);
????????
????????HibernateSessionFactory.closeSession();
????????
????????Session?session?
=
?HibernateSessionFactory.currentSession();
????Transaction?tr1?
=
?session.beginTransaction();
????????
//
t1?成為?持久狀態(tài)?一級(jí)緩存中?加載
????????session.saveOrUpdate(t1oo);?
????????
//
直接一條語(yǔ)句刪除T1oo，緩存無(wú)法同步
????????
//
一級(jí)緩存中還有?t1
????????Query?qu?
=
?session.createQuery(
"
delete?T1oo
"
);
????????
try
?{
????????????qu.executeUpdate();
????????}?
catch
?(Exception?e)?{????
????????????System.out.println(
"
//err:?有級(jí)聯(lián)?單使用?delete?T1oo?還要delete?T2oo.aid?=?T1oo.id//
"
);
????????????List?list?
=
?session.createQuery(
"
from?T1oo
"
).list();
????????????
for
(Iterator?it
=
list.iterator();it.hasNext();){
????????????????Query?t2qu?
=
?session.createQuery(
"
delete?T2oo??where?aid=:id
"
);
????????????????t2qu.setInteger(
"
id
"
,?((T1oo)it.next()).getId().intValue());
????????????????t2qu.executeUpdate();????????????????
????????????}
????????????qu.executeUpdate();
????????}
????????
????????tr1.commit();
????????
????Transaction?tr2?
=
?session.beginTransaction();
????????
//
這直接通過一級(jí)緩存中加載t2，但DB中以沒有此條數(shù)據(jù)
????????t1oo?
=
?(T1oo)session.load(T1oo.
class
,t1oo.getId());
????????t1oo.setName(
"
google
"
);
????????
try
?{
????????????tr2.commit();????
????????}?
catch
?(Exception?e)?{
????????????System.out.println(
"
//err:?update(t1oo)->DB?中數(shù)據(jù)庫(kù)中沒有?t1oo?//
"
);
????????}
????????
????????System.out.println(
"
?一級(jí)緩存清空前?
"
+
?session.get(T1oo.
class
,t1oo.getId())?);
????????session.evict(t1oo);
????????System.out.println(
"
?一級(jí)緩存清空后?
"
+
?session.get(T1oo.
class
,t1oo.getId())?);
????????
????????
//
不把t1oo?id?為空，否則當(dāng)在saveOrUpdate時(shí)候就會(huì)以為是游離態(tài)?update了
????????t1oo.setId(
null
);
????????
//
id=null?insert?調(diào)用
????????session.saveOrUpdate(t1oo);????????
????????tr2.commit();
????????
????Transaction?tr3?
=
?session.beginTransaction();
????????session.delete(t1oo);
????????tr3.commit();
????????
????????session.close();
????????HibernateSessionFactory.closeSession();
????????
????}
結(jié)果是：
********************ExecuteUpdate************************
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment).
log4j:WARN Please initialize the log4j system properly.
Hibernate: insert into t1oo (name, id) values (?, ?)
Hibernate: delete from t1oo
//err: 有級(jí)聯(lián) 單使用 delete T1oo 還要delete T2oo.aid = T1oo.id//
Hibernate: select t1oo0_.id as id, t1oo0_.name as name0_ from t1oo t1oo0_
Hibernate: delete from t2oo where aid=?
Hibernate: delete from t2oo where aid=?
Hibernate: delete from t2oo where aid=?
Hibernate: delete from t1oo
Hibernate: update t1oo set name=? where id=?
//err: update(t1oo)->DB 中數(shù)據(jù)庫(kù)中沒有 t1oo //
?一級(jí)緩存清空前 hbn.bean.T1oo@287
Hibernate: select t1oo0_.id as id0_, t1oo0_.name as name0_0_ from t1oo t1oo0_ where t1oo0_.id=?
?一級(jí)緩存清空后 null
Hibernate: insert into t1oo (name, id) values (?, ?)
Hibernate: delete from t1oo where id=?
Get Load 區(qū)別 ：
?????/**?Get?Load?區(qū)別?(在commit前要?session.flush())
?????*?Table?->?T1oo(id,name)
?????*?1.如果未能發(fā)現(xiàn)符合條件的記錄，get方法返回null，而load方法會(huì)拋出異常
?????*?2.Load方法可返回實(shí)體的代理類實(shí)例，而get方法永遠(yuǎn)直接返回實(shí)體類。
?????*?3.load方法可以充分利用內(nèi)部緩存和二級(jí)緩存中的現(xiàn)有數(shù)據(jù)，而get方法則僅僅在內(nèi)部緩存中進(jìn)行數(shù)據(jù)查找，
?????*?????????????如沒有發(fā)現(xiàn)對(duì)應(yīng)數(shù)據(jù)，將越過二級(jí)緩存，直接調(diào)用SQL完成數(shù)據(jù)讀取。?
?????*/
????public?void?testGetLoad()?throws?Exception?{
????????System.out.println("\r\n\r\n********************Get<>Load************************");
????????Session?session?=?HibernateSessionFactory.currentSession();
????//??數(shù)據(jù)準(zhǔn)備
????????T1oo?t1oo?=?new?T1oo();
????????t1oo.setName("liu");
????Transaction?t1?=?session.beginTransaction();
????????session.saveOrUpdate(t1oo);
????????//?為什么這會(huì)錯(cuò)？
????????//session.evict(t1oo);
????????//session.flush();
????????t1.commit();
????????session.evict(t1oo);
????
????Transaction?t2?=?session.beginTransaction();
????????System.out.println("一級(jí)緩存是否有t1oo(load)->"+session.contains(t1oo));?
????????//這時(shí)候t1oo為?CGlib生成的代理類
????????t1oo?=?(T1oo)session.load(T1oo.class,t1oo.getId());
????????System.out.println("?延遲加載出現(xiàn)：select..?t1oo0_.id=??表的其他屬性加載?");
????????t1oo.setName("load?list");
????????//后在?update
????????t2.commit();
????????session.evict(t1oo);
????????
????Transaction?t3?=?session.beginTransaction();
????????System.out.println("一級(jí)緩存是否有t1oo(get)->"+session.contains(t1oo));?
????????//這時(shí)候t1oo為?CGlib生成的代理類
????????t1oo?=?(T1oo)session.get(T1oo.class,t1oo.getId());
????????System.out.println("?沒有延遲加載出現(xiàn)");
????????t1oo.setName("get?list");
????????//后在?update
????????t3.commit();????
????????session.evict(t1oo);
????????
????Transaction?tr3?=?session.beginTransaction();
????????session.delete(t1oo);
????????tr3.commit();
????????
????????session.close();
????????HibernateSessionFactory.closeSession();
????????
????}
結(jié)果
********************Get<>Load************************
Hibernate: insert into t1oo (name, id) values (?, ?)
一級(jí)緩存是否有t1oo(load)->false
?延遲加載出現(xiàn)：select.. t1oo0_.id=? 表的其他屬性加載
Hibernate: select t1oo0_.id as id0_, t1oo0_.name as name0_0_ from t1oo t1oo0_ where t1oo0_.id=?
Hibernate: update t1oo set name=? where id=?
一級(jí)緩存是否有t1oo(get)->false
Hibernate: select t1oo0_.id as id0_, t1oo0_.name as name0_0_ from t1oo t1oo0_ where t1oo0_.id=?
?沒有延遲加載出現(xiàn)
Hibernate: update t1oo set name=? where id=?
Hibernate: select t2ooset0_.aid as aid1_, t2ooset0_.id as id1_, t2ooset0_.id as id0_, t2ooset0_.avg as avg1_0_, t2ooset0_.aid as aid1_0_ from t2oo t2ooset0_ where t2ooset0_.aid=?
Hibernate: delete from t1oo where id=?
Set 集合的識(shí)別：
????/**?Set?集合的識(shí)別
?????*?Table?->?T1oo(id,name)
?????*?Table?->?T2oo(id,avg,aid)
?????*?外鍵?T1oo.id->T2oo.aid
?????*?T1oo??<set?name="t2ooSet"?inverse="false"?cascade?=?"all"??>
?????*?T2oo??<many-to-one?name="t1oo"?column="aid"?class="T1oo"?/>
?????*?cascade='insert'?是一定要的
?????*?????當(dāng)?T1oo沒有?inverse="true"?主動(dòng)權(quán)的時(shí)候，要雙項(xiàng)關(guān)聯(lián)
?????*?????t1oo.getT2ooSet().add(t2oo1);
?????*????t1oo.getT2ooSet().add(t2oo2);
?????*????t2oo1.setT1oo(t1oo);
?????*????t2oo2.setT1oo(t1oo);
?????*??要不后sql為：
?????*??Hibernate:?insert?into?t2oo?(avg,?aid,?id)?values?(?,??,??)
?????*????Hibernate:?insert?into?t2oo?(avg,?aid,?id)?values?(?,??,??)
?????*????+----+-----+------+
?????*????|?id?|?avg?|?aid??|
?????*????+----+-----+------+
?????*????|??1?|??24?|?NULL?|
?????*????|??2?|??23?|?NULL?|
?????*????+----+-----+------+
?????*????當(dāng)?T1oo有?inverse="false"主動(dòng)權(quán)的時(shí)候
?????*??t1oo.getT2ooSet().add(t2oo1);
?????*????t1oo.getT2ooSet().add(t2oo2);
?????*??Sql語(yǔ)句為：
?????*??Hibernate:?insert?into?t1oo?(name,?id)?values?(?,??)
?????*????Hibernate:?insert?into?t2oo?(avg,?aid,?id)?values?(?,??,??)
?????*????Hibernate:?insert?into?t2oo?(avg,?aid,?id)?values?(?,??,??)
?????*????Hibernate:?update?t2oo?set?aid=??where?id=?
?????*????Hibernate:?update?t2oo?set?aid=??where?id=?
?????*????|??3?|??24?|???12?|
?????*????|??4?|??23?|???12?|
?????*????+----+-----+------+
????*/
????public?void?testSet(){
????????System.out.println("\r\n\r\n********************Set************************");
????????T1oo?t1oo?=?new?T1oo();
????????t1oo.setName("list");
????????
????????T2oo?t2oo1?=?new?T2oo();?t2oo1.setAvg(new?Integer(23));
????????T2oo?t2oo2?=?new?T2oo();?t2oo2.setAvg(new?Integer(24));
????????
????????
????????Session?session?=?HibernateSessionFactory.currentSession();
????????Transaction?tr1?=?session.beginTransaction();
????????session.save(t1oo);
????????t1oo?=?(T1oo)?session.load(T1oo.class,t1oo.getId());
????????t1oo.setT2ooSet(new?HashSet())?;
????????t1oo.getT2ooSet().add(t2oo1);
????????t1oo.getT2ooSet().add(t2oo2);
?????????
????????System.out.println(?t1oo.getT2ooSet().size()+""?);????????
????????tr1.commit();
????????
????????System.out.println();
????????T2oo?t2oo3?=?new?T2oo();?t2oo3.setAvg(new?Integer(25));
????????T1oo?t1oo2?=?new?T1oo();?t1oo2.setName("mz");
????????t2oo3.setT1oo(t1oo2);
????????
????????Transaction?tr2?=?session.beginTransaction();
????????session.save(t2oo3);
????????try?{
????????????tr2.commit();????
????????}?catch?(Exception?e)?{
????????????System.out.println("//err:?沒有主動(dòng)權(quán)?cascade?=?'all'?不可以級(jí)聯(lián)save?t1oo???//");
????????}
????????session.close();
????????HibernateSessionFactory.closeSession();
????}
???
結(jié)果是：
********************Set************************
2
Hibernate: insert into t1oo (name, id) values (?, ?)
Hibernate: insert into t2oo (avg, aid, id) values (?, ?, ?)
Hibernate: insert into t2oo (avg, aid, id) values (?, ?, ?)
Hibernate: update t2oo set aid=? where id=?
Hibernate: update t2oo set aid=? where id=?
//err: 沒有主動(dòng)權(quán) cascade = 'all' 不可以級(jí)聯(lián)save t1oo?? //
評(píng)論
# re: hibernate 部分問題總結(jié)——1[未登錄] 回復(fù) 更多評(píng)論
2009-02-14 11:23 by
session.close();
HibernateSessionFactory.closeSession();
為什么要調(diào)用兩次
第一次 session.close(); 為本線程的session關(guān)閉
HibernateSessionFactory.closeSession(); 第二次為 全部連接斷開
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