我正在尝试更新不同事务中的同一行，以了解Hibernate的乐观锁定。
但我没有得到任何StaleObjectStateException或任何其他异常。
public void updateUsingTwoThreads() throws InterruptedException {
Thread t1 = new Thread(new Runnable() {
public void run() {
Session session = null;
try {
session = HibernateUtil.getSessionFactory().openSession();
org.hibernate.Transaction transaction = session
.beginTransaction();
Airline airline = (Airline) session.get(Airline.class,
new Integer(1));
System.out.println("getVersion in "+airline.getVersion()+"in "+ Thread.currentThread().getName());
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
airline.setAirlineCode("asdasd234phle");
session.saveOrUpdate(airline);
System.out.println("getVersion in "+airline.getVersion()+"in "+ Thread.currentThread().getName());
transaction.commit();
}catch(Throwable t){
System.out.println(t);
}finally {
session.close();
}
}
},"earlier");
Thread t2 = new Thread(new Runnable() {
public void run() {
Session session = null;
try {
session = HibernateUtil.getSessionFactory().openSession();
//session.clear();
org.hibernate.Transaction transaction = session.beginTransaction();
Airline airline = (Airline) session.get(Airline.class,new Integer(1));
System.out.println("getVersion in "+airline.getVersion()+"in "+ Thread.currentThread().getName());
try {
Thread.sleep(100000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("getVersion in "+airline.getVersion()+"in "+ Thread.currentThread().getName());
airline.setAirlineCode("asdasdbaadmain");
session.saveOrUpdate(airline);
transaction.commit();
}catch(Throwable t){
System.out.println(t);
} finally {
session.close();
}
}
},"later");
t1.start();
t2.start();
t1.join();
t2.join();
}
我已将代码附加到我正在尝试的内容之上。请让我知道..我错过了什么吗？
或乐观锁定与我正在尝试的不同。
在上面的代码中，我已经启动了两个线程“Earlier”和“Later”，它们都从sessionFactory获取会话对象，并从Database加载相同的记录并同时更新它。
1）但是没有异常，并且只有一个线程能够更新该行。
航空公司课程如下：
package tryouts.one_to_many;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Version;
import org.hibernate.annotations.OptimisticLockType;
@Entity
@org.hibernate.annotations.Entity(dynamicUpdate=true, optimisticLock = OptimisticLockType.ALL)
public class Airline implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "AIRLINE_ID")
private Integer airlineId;
@Column(name = "AIRLINE_NAME")
private String airlineName;
@Column(name = "AIRLINE_CODE")
private String airlineCode;
@Version
private long version;
@OneToMany
@JoinColumn(name="airlineId")
private Set<AirlineFlight> airlineFlights = new HashSet<AirlineFlight>();
public Integer getAirlineId() {
return airlineId;
}
public void setAirlineId(Integer airlineId) {
this.airlineId = airlineId;
}
public String getAirlineName() {
return airlineName;
}
public void setAirlineName(String airlineName) {
this.airlineName = airlineName;
}
public String getAirlineCode() {
return airlineCode;
}
public void setAirlineCode(String airlineCode) {
this.airlineCode = airlineCode;
}
public Set<AirlineFlight> getAirlineFlights() {
return airlineFlights;
}
public void setAirlineFlights(Set<AirlineFlight> airlineFlights) {
this.airlineFlights = airlineFlights;
}
public long getVersion() {
return version;
}
public void setVersion(long version) {
this.version = version;
}
}
编程OutPut：
04:25:29.656 [earlier] DEBUG org.hibernate.impl.SessionImpl - opened session at timestamp: 13645311296
04:25:29.656 [later] DEBUG org.hibernate.impl.SessionImpl - opened session at timestamp: 13645311296
04:25:29.657 [earlier] DEBUG o.h.transaction.JDBCTransaction - begin
04:25:29.657 [later] DEBUG o.h.transaction.JDBCTransaction - begin
04:25:29.657 [earlier] DEBUG org.hibernate.jdbc.ConnectionManager - opening JDBC connection
04:25:29.657 [later] DEBUG org.hibernate.jdbc.ConnectionManager - opening JDBC connection
04:25:29.657 [earlier] DEBUG o.h.transaction.JDBCTransaction - current autocommit status: false
04:25:29.657 [later] DEBUG o.h.c.DriverManagerConnectionProvider - opening new JDBC connection
04:25:29.659 [earlier] DEBUG org.hibernate.loader.Loader - loading entity: [tryouts.one_to_many.Airline#1]
04:25:29.663 [earlier] DEBUG org.hibernate.jdbc.AbstractBatcher - about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
04:25:29.663 [earlier] DEBUG org.hibernate.SQL - select airline0_.AIRLINE_ID as AIRLINE1_0_0_, airline0_.AIRLINE_CODE as AIRLINE2_0_0_, airline0_.AIRLINE_NAME as AIRLINE3_0_0_, airline0_.version as version0_0_ from Airline airline0_ where airline0_.AIRLINE_ID=?
Hibernate: select airline0_.AIRLINE_ID as AIRLINE1_0_0_, airline0_.AIRLINE_CODE as AIRLINE2_0_0_, airline0_.AIRLINE_NAME as AIRLINE3_0_0_, airline0_.version as version0_0_ from Airline airline0_ where airline0_.AIRLINE_ID=?
04:25:29.680 [later] DEBUG o.h.c.DriverManagerConnectionProvider - created connection to: jdbc:mysql://localhost:3306/test, Isolation Level: 4
04:25:29.681 [later] DEBUG o.h.transaction.JDBCTransaction - current autocommit status: false
04:25:29.681 [later] DEBUG org.hibernate.loader.Loader - loading entity: [tryouts.one_to_many.Airline#1]
04:25:29.681 [later] DEBUG org.hibernate.jdbc.AbstractBatcher - about to open PreparedStatement (open PreparedStatements: 0, globally: 1)
04:25:29.681 [later] DEBUG org.hibernate.SQL - select airline0_.AIRLINE_ID as AIRLINE1_0_0_, airline0_.AIRLINE_CODE as AIRLINE2_0_0_, airline0_.AIRLINE_NAME as AIRLINE3_0_0_, airline0_.version as version0_0_ from Airline airline0_ where airline0_.AIRLINE_ID=?
Hibernate: select airline0_.AIRLINE_ID as AIRLINE1_0_0_, airline0_.AIRLINE_CODE as AIRLINE2_0_0_, airline0_.AIRLINE_NAME as AIRLINE3_0_0_, airline0_.version as version0_0_ from Airline airline0_ where airline0_.AIRLINE_ID=?
04:25:29.682 [later] DEBUG org.hibernate.jdbc.AbstractBatcher - about to open ResultSet (open ResultSets: 0, globally: 0)
04:25:29.682 [earlier] DEBUG org.hibernate.jdbc.AbstractBatcher - about to open ResultSet (open ResultSets: 0, globally: 0)
04:25:29.683 [later] DEBUG org.hibernate.loader.Loader - result row: EntityKey[tryouts.one_to_many.Airline#1]
04:25:29.683 [earlier] DEBUG org.hibernate.loader.Loader - result row: EntityKey[tryouts.one_to_many.Airline#1]
04:25:29.687 [later] DEBUG org.hibernate.jdbc.AbstractBatcher - about to close ResultSet (open ResultSets: 1, globally: 2)
04:25:29.687 [earlier] DEBUG org.hibernate.jdbc.AbstractBatcher - about to close ResultSet (open ResultSets: 1, globally: 2)
04:25:29.687 [later] DEBUG org.hibernate.jdbc.AbstractBatcher - about to close PreparedStatement (open PreparedStatements: 1, globally: 2)
04:25:29.687 [earlier] DEBUG org.hibernate.jdbc.AbstractBatcher - about to close PreparedStatement (open PreparedStatements: 1, globally: 2)
04:25:29.688 [later] DEBUG org.hibernate.engine.TwoPhaseLoad - resolving associations for [tryouts.one_to_many.Airline#1]
04:25:29.689 [earlier] DEBUG org.hibernate.engine.TwoPhaseLoad - resolving associations for [tryouts.one_to_many.Airline#1]
04:25:29.695 [earlier] DEBUG org.hibernate.engine.TwoPhaseLoad - done materializing entity [tryouts.one_to_many.Airline#1]
04:25:29.695 [later] DEBUG org.hibernate.engine.TwoPhaseLoad - done materializing entity [tryouts.one_to_many.Airline#1]
04:25:29.695 [earlier] DEBUG o.h.e.StatefulPersistenceContext - initializing non-lazy collections
04:25:29.695 [later] DEBUG o.h.e.StatefulPersistenceContext - initializing non-lazy collections
04:25:29.695 [earlier] DEBUG org.hibernate.loader.Loader - done entity load
04:25:29.695 [later] DEBUG org.hibernate.loader.Loader - done entity load
getVersion in 53in earlier
getVersion in 53in later
getVersion in 53in earlier
04:25:31.697 [earlier] DEBUG o.h.transaction.JDBCTransaction - commit
04:25:31.697 [earlier] DEBUG o.h.e.d.AbstractFlushingEventListener - processing flush-time cascades
04:25:31.699 [earlier] DEBUG o.h.e.d.AbstractFlushingEventListener - dirty checking collections
04:25:31.704 [earlier] DEBUG org.hibernate.engine.Collections - Collection found: [tryouts.one_to_many.Airline.airlineFlights#1], was: [tryouts.one_to_many.Airline.airlineFlights#1] (uninitialized)
04:25:31.704 [earlier] DEBUG o.h.e.d.AbstractFlushingEventListener - Flushed: 0 insertions, 1 updates, 0 deletions to 1 objects
04:25:31.704 [earlier] DEBUG o.h.e.d.AbstractFlushingEventListener - Flushed: 0 (re)creations, 0 updates, 0 removals to 1 collections
04:25:31.705 [earlier] DEBUG org.hibernate.pretty.Printer - listing entities:
04:25:31.705 [earlier] DEBUG org.hibernate.pretty.Printer - tryouts.one_to_many.Airline{airlineFlights=<uninitialized>, airlineCode=asdasd234phle, airlineName=Jet Airways, airlineId=1, version=53}
04:25:31.707 [earlier] DEBUG org.hibernate.jdbc.AbstractBatcher - about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
04:25:31.707 [earlier] DEBUG org.hibernate.SQL - update Airline set AIRLINE_CODE=?, version=? where AIRLINE_ID=? and version=?
Hibernate: update Airline set AIRLINE_CODE=?, version=? where AIRLINE_ID=? and version=?
04:25:31.708 [earlier] DEBUG org.hibernate.jdbc.AbstractBatcher - about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
04:25:31.711 [earlier] DEBUG o.h.transaction.JDBCTransaction - committed JDBC Connection
04:25:31.711 [earlier] DEBUG org.hibernate.jdbc.ConnectionManager - aggressively releasing JDBC connection
04:25:31.711 [earlier] DEBUG org.hibernate.jdbc.ConnectionManager - releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
getVersion in 53in later
04:27:09.695 [later] DEBUG o.h.transaction.JDBCTransaction - commit
04:27:09.696 [later] DEBUG o.h.e.d.AbstractFlushingEventListener - processing flush-time cascades
04:27:09.696 [later] DEBUG o.h.e.d.AbstractFlushingEventListener - dirty checking collections
04:27:09.696 [later] DEBUG org.hibernate.engine.Collections - Collection found: [tryouts.one_to_many.Airline.airlineFlights#1], was: [tryouts.one_to_many.Airline.airlineFlights#1] (uninitialized)
04:27:09.696 [later] DEBUG o.h.e.d.AbstractFlushingEventListener - Flushed: 0 insertions, 0 updates, 0 deletions to 1 objects
04:27:09.696 [later] DEBUG o.h.e.d.AbstractFlushingEventListener - Flushed: 0 (re)creations, 0 updates, 0 removals to 1 collections
04:27:09.696 [later] DEBUG org.hibernate.pretty.Printer - listing entities:
04:27:09.696 [later] DEBUG org.hibernate.pretty.Printer - tryouts.one_to_many.Airline{airlineFlights=<uninitialized>, airlineCode=asdasdbaadmain, airlineName=Jet Airways, airlineId=1, version=53}
04:27:09.697 [later] DEBUG o.h.transaction.JDBCTransaction - committed JDBC Connection
04:27:09.697 [later] DEBUG org.hibernate.jdbc.ConnectionManager - aggressively releasing JDBC connection
04:27:09.697 [later] DEBUG org.hibernate.jdbc.ConnectionManager - releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
答案 0 :(得分：2)
这里发生的事情是一个脏检查的情况，帮助你在你不期望的时候。我打赌airlineCode的原始值为asdasdbaadmain，与您在'后来'主题中设置的相同。
Hibernate有一个称为脏检查的进程，它检查每个字段以查看它是否已从最初加载的状态进行了修改。在这种情况下，您没有更改任何内容。没有未更改的字段表示没有更新，没有执行SQL，没有版本冲突，因此没有例外。
如果你调用session.evict()，你得到异常的事实是因为如果你已经从Session驱逐了实体那么就没有什么可以进行脏检查了，所以Hibernate被迫写入数据库。