我是Java / Hibernate / Seam开发方式的新手，但我似乎对Hibernate和并发线程有一个奇怪的问题。
我有一个应用程序范围的Seam组件，它通过EJB计时器以设定的间隔（Orchestrator.java）执行，调用方法 startProcessingWorkloads 。
此方法有一个注入的EntityManager，用于检查数据库中的数据集合，如果找到工作集合，则会创建一个新的异步Seam组件（LoadContoller.java）并执行 start（）控制器上的方法
LoadController已注入EntityManager并使用它来执行非常大的事务（大约一小时）
一旦LoadController作为一个单独的线程运行，Orchestrator仍然以设定的间隔作为线程执行，例如
1分钟
Orchestrator - 寻找工作集（找不到）（线程1）
2分钟
Orchestrator - 查找工作集（找到一个，Starts LoadController）（线程1）
LoadController - 开始更新数据库记录（线程2）
3分钟
Orchestrator - 寻找工作集（找不到）（线程1）
LoadController - 仍在更新数据库记录（线程2）
4分钟
Orchestrator - 寻找工作集（找不到）（线程1）
LoadController - 仍在更新数据库记录（线程2）
5分钟
Orchestrator - 寻找工作集（找不到）（线程1）
LoadController - 完成更新数据库记录（线程2）
6分钟
Orchestrator - 寻找工作集（找不到）（线程1）
7分钟
Orchestrator - 寻找工作集（找不到）（主题1）
但是，当Orchestrator与LoadController同时运行时，我收到间歇性错误（见下文）。
5：10：40,852警告[AbstractBatcher] 异常清算 maxRows进行/的QueryTimeout java.sql.SQLException：连接是 与托管无关 connection.org.jboss.resource.adapter.jdbc.jdk6.WrappedConnectionJDK6@1fcdb21
在Orchestrator完成其SQl查询并且LoadController尝试执行其下一个SQl查询后，抛出此错误。
我做了一些研究，我得出的结论是EntityManager正在关闭，因此LoadController无法使用它。
现在混淆了什么完全关闭了连接我做了一些Orchestrator和LoadController使用的实体管理器对象的基本对象转储，当调用每个组件时，我发现在我收到上述错误之前发生这种情况
2010-07-30 15：06：40,804 INFO [processManagement.LoadController] （池-15-螺纹-2） org.jboss.seam.persistence.EntityManagerProxy@7e3da1
2010-07-30 15：10：40,758 INFO [processManagement.Orchestrator] （池-15-螺纹-1） org.jboss.seam.persistence.EntityManagerProxy@7e3da1
似乎在其中一个Orchestrator执行间隔期间，它获得了对LoadController当前使用的同一EntityManager的引用。当Orchestrator完成其SQL执行时，它会关闭连接，而LoadController无法再执行其更新。
所以我的问题是，有没有人知道这件事发生过，还是让我的线程在这段代码中搞砸了？
根据我的理解，在注入EntityManager时，从EntityManagerFactory注入一个新实例，该实例保留在该特定对象之前，直到对象离开范围（在这种情况下，它们是无状态的，因此当 start（）方法结束时），如何将实体管理器的同一实例注入两个独立的线程？
Orchestrator.java
@Name("processOrchestrator")
@Scope(ScopeType.APPLICATION)
@AutoCreate
public class Orchestrator {
//___________________________________________________________
@Logger Log log;
@In EntityManager entityManager;
@In LoadController loadController;
@In WorkloadManager workloadManager;
//___________________________________________________________
private int fProcessInstanceCount = 0;
//___________________________________________________________
public Orchestrator() {}
//___________________________________________________________
synchronized private void incrementProcessInstanceCount() {
fProcessInstanceCount++;
}
//___________________________________________________________
synchronized private void decreaseProcessInstanceCount() {
fProcessInstanceCount--;
}
//___________________________________________________________
@Observer("controllerExceptionEvent")
synchronized public void controllerExceptionListiner(Process aProcess, Exception aException) {
decreaseProcessInstanceCount();
log.info(
"Controller " + String.valueOf(aProcess) +
" failed with the error [" + aException.getMessage() + "]"
);
Events.instance().raiseEvent(
Application.ApplicationEvent.applicationExceptionEvent.name(),
aException,
Orchestrator.class
);
}
//___________________________________________________________
@Observer("controllerCompleteEvent")
synchronized public void successfulControllerCompleteListiner(Process aProcess, long aWorkloadId) {
try {
MisWorkload completedWorklaod = entityManager.find(MisWorkload.class, aWorkloadId);
workloadManager.completeWorkload(completedWorklaod);
} catch (Exception ex) {
log.error(ex.getMessage(), ex);
}
decreaseProcessInstanceCount();
log.info("Controller " + String.valueOf(aProcess) + " completed successfuly");
}
//___________________________________________________________
@Asynchronous
public void startProcessingWorkloads(@IntervalDuration long interval) {
log.info("Polling for workloads.");
log.info(entityManager.toString());
try {
MisWorkload pendingWorkload = workloadManager.getNextPendingWorkload();
if (pendingWorkload != null) {
log.info(
"Pending Workload found (Workload_Id = " +
String.valueOf(pendingWorkload.getWorkloadId()) +
"), starting process controller."
);
Process aProcess = pendingWorkload.retriveProcessIdAsProcess();
ControllerIntf controller = createWorkloadController(aProcess);
if (controller != null) {
controller.start(aProcess, pendingWorkload.getWorkloadId());
workloadManager.setWorkloadProcessing(pendingWorkload);
}
}
} catch (Exception ex) {
Events.instance().raiseEvent(
Application.ApplicationEvent.applicationExceptionEvent.name(),
ex,
Orchestrator.class
);
}
log.info("Polling complete.");
}
//___________________________________________________________
private ControllerIntf createWorkloadController(Process aProcess) {
ControllerIntf newController = null;
switch(aProcess) {
case LOAD:
newController = loadController;
break;
default:
log.info(
"createWorkloadController() does not know the value (" +
aProcess.name() +
") no controller will be started."
);
}
// If a new controller is created than increase the
// count of started controllers so that we know how
// many are running.
if (newController != null) {
incrementProcessInstanceCount();
}
return newController;
}
//___________________________________________________________
}
LoadController.java
@Name("loadController")
@Scope(ScopeType.STATELESS)
@AutoCreate
public class LoadController implements ControllerIntf {
//__________________________________________________
@Logger private Log log;
@In private EntityManager entityManager;
//__________________________________________________
private String fFileName = "";
private String fNMDSFileName = "";
private String fAddtFileName = "";
//__________________________________________________
public LoadController(){ }
//__________________________________________________
@Asynchronous
synchronized public void start(Process aProcess, long aWorkloadId) {
log.info(
LoadController.class.getName() +
" process thread was started for WorkloadId [" +
String.valueOf(aWorkloadId) + "]."
);
log.info(entityManager.toString());
try {
Query aQuery = entityManager.createQuery(
"from MisLoad MIS_Load where Workload_Id = " + String.valueOf(aWorkloadId)
);
MisLoad misLoadRecord = (MisLoad)aQuery.getSingleResult();
fFileName =
misLoadRecord.getInitiatedBy().toUpperCase() + "_" +
misLoadRecord.getMdSourceSystem().getMdState().getShortName() + "_" +
DateUtils.now(DateUtils.FORMAT_FILE) + ".csv"
;
fNMDSFileName = "NMDS_" + fFileName;
fAddtFileName = "Addt_" + fFileName;
createDataFile(misLoadRecord.getFileContents());
ArrayList<String>sasCode = generateSASCode(
misLoadRecord.getLoadId(),
misLoadRecord.getMdSourceSystem().getPreloadFile()
);
//TODO: As the sas password will be encrypted in the database, we will
// need to decrypt it before passing to the below function
executeLoadSASCode(
sasCode,
misLoadRecord.getInitiatedBy(),
misLoadRecord.getSasPassword()
);
createWorkloadContentRecords(aWorkloadId, misLoadRecord.getLoadId());
//TODO: Needs to remove password from DB when complete
removeTempCSVFiles();
Events.instance().raiseEvent(
Application.ApplicationEvent.controllerCompleteEvent.name(),
aProcess,
aWorkloadId
);
log.info(LoadController.class.getName() + " process thread completed.");
} catch (Exception ex) {
Events.instance().raiseEvent(
Application.ApplicationEvent.controllerExceptionEvent.name(),
aProcess,
ex
);
}
}
//__________________________________________________
private void createDataFile(byte[] aFileContent) throws Exception {
File dataFile =
new File(ECEConfig.getConfiguration().sas_tempFileDir() + "\\" + fFileName);
FileUtils.writeBytesToFile(dataFile, aFileContent, true);
}
//__________________________________________________
private ArrayList<String> generateSASCode(long aLoadId, String aSourceSystemPreloadSasFile) {
String sasTempDir = ECEConfig.getConfiguration().sas_tempFileDir();
ArrayList<String> sasCode = new ArrayList<String>();
sasCode.add("%let sOracleUserId = " + ECEConfig.getConfiguration().oracle_username() + ";");
sasCode.add("%let sOraclePassword = " + ECEConfig.getConfiguration().oracle_password() + ";");
sasCode.add("%let sOracleSID = " + ECEConfig.getConfiguration().oracle_sid() + ";");
sasCode.add("%let sSchema = " + ECEConfig.getConfiguration().oracle_username() + ";");
sasCode.add("%let sECESASSourceDir = " + ECEConfig.getConfiguration().sas_sourceDir() + ";");
sasCode.add("libname lOracle ORACLE user=&sOracleUserId pw=&sOraclePassword path=&sOracleSID schema=&sSchema;");
sasCode.add("%let sCommaDelimiter = %str(" + ECEConfig.getConfiguration().dataload_csvRawDataFileDelimiter() + ");");
sasCode.add("%let sPipeDelimiter = %nrquote(" + ECEConfig.getConfiguration().dataload_csvNMDSDataFileDelimiter() + ");");
sasCode.add("%let sDataFileLocation = " + sasTempDir + "\\" + fFileName + ";");
sasCode.add("%let sNMDSOutputDataFileLoc = " + sasTempDir + "\\" + fNMDSFileName + ";");
sasCode.add("%let sAddtOutputDataFileLoc = " + sasTempDir + "\\" + fAddtFileName + ";");
sasCode.add("%let iLoadId = " + String.valueOf(aLoadId) + ";");
sasCode.add("%include \"&sECESASSourceDir\\ECE_UtilMacros.sas\";");
sasCode.add("%include \"&sECESASSourceDir\\" + aSourceSystemPreloadSasFile + "\";");
sasCode.add("%include \"&sECESASSourceDir\\ECE_NMDSLoad.sas\";");
sasCode.add("%preload(&sDataFileLocation, &sCommaDelimiter, &sNMDSOutputDataFileLoc, &sAddtOutputDataFileLoc, &sPipeDelimiter);");
sasCode.add("%loadNMDS(lOracle, &sNMDSOutputDataFileLoc, &sAddtOutputDataFileLoc, &sPipeDelimiter, &iLoadId);");
return sasCode;
}
//__________________________________________________
private void executeLoadSASCode(
ArrayList<String> aSasCode, String aUserName, String aPassword) throws Exception
{
SASExecutor aSASExecutor = new SASExecutor(
ECEConfig.getConfiguration().sas_server(),
ECEConfig.getConfiguration().sas_port(),
aUserName,
aPassword
);
aSASExecutor.execute(aSasCode);
log.info(aSASExecutor.getCompleteSasLog());
}
//__________________________________________________
/**
* Creates the MIS_UR_Workload_Contents records for
* the ECE Unit Record data that was just loaded
*
* @param aWorkloadId
* @param aMisLoadId
* @throws Exception
*/
private void createWorkloadContentRecords(long aWorkloadId, long aMisLoadId) throws Exception {
String selectionRule =
" from EceUnitRecord ECE_Unit_Record where ECE_Unit_Record.loadId = " +
String.valueOf(aMisLoadId)
;
MisWorkload misWorkload = entityManager.find(MisWorkload.class, aWorkloadId);
SeamManualTransaction manualTx = new SeamManualTransaction(
entityManager,
ECEConfig.getConfiguration().manualSeamTxTimeLimit()
);
manualTx.begin();
RecordPager oPager = new RecordPager(
entityManager,
selectionRule,
ECEConfig.getConfiguration().recordPagerDefaultPageSize()
);
Object nextRecord = null;
while ((nextRecord = oPager.getNextRecord()) != null) {
EceUnitRecord aEceUnitRecord = (EceUnitRecord)nextRecord;
MisUrWorkloadContents aContentsRecord = new MisUrWorkloadContents();
aContentsRecord.setEceUnitRecordId(aEceUnitRecord.getEceUnitRecordId());
aContentsRecord.setMisWorkload(misWorkload);
aContentsRecord.setProcessOutcome('C');
entityManager.persist(aContentsRecord);
}
manualTx.commit();
}
/**
* Removes the CSV temp files that are created for input
* into the SAS server and that are created as output.
*/
private void removeTempCSVFiles() {
String sasTempDir = ECEConfig.getConfiguration().sas_tempFileDir();
File dataInputCSV = new File(sasTempDir + "\\" + fFileName);
File nmdsOutputCSV = new File(sasTempDir + "\\" + fNMDSFileName);
File addtOutputCSV = new File(sasTempDir + "\\" + fAddtFileName);
if (dataInputCSV.exists()) {
dataInputCSV.delete();
}
if (nmdsOutputCSV.exists()) {
nmdsOutputCSV.delete();
}
if (addtOutputCSV.exists()) {
addtOutputCSV.delete();
}
}
}
SeamManualTransaction.java
public class SeamManualTransaction {
//___________________________________________________________
private boolean fObjectUsed = false;
private boolean fJoinExistingTransaction = true;
private int fTransactionTimeout = 60; // Default: 60 seconds
private UserTransaction fUserTx;
private EntityManager fEntityManager;
//___________________________________________________________
/**
* Set the transaction timeout in milliseconds (from minutes)
*
* @param aTimeoutInMins The number of minutes to keep the transaction active
*/
private void setTransactionTimeout(int aTimeoutInSecs) {
// 60 * aTimeoutInSecs = Timeout in Seconds
fTransactionTimeout = 60 * aTimeoutInSecs;
}
//___________________________________________________________
/**
* Constructor
*
* @param aEntityManager
*/
public SeamManualTransaction(EntityManager aEntityManager) {
fEntityManager = aEntityManager;
}
//___________________________________________________________
/**
* Constructor
*
* @param aEntityManager
* @param aTimeoutInSecs
*/
public SeamManualTransaction(EntityManager aEntityManager, int aTimeoutInSecs) {
setTransactionTimeout(aTimeoutInSecs);
fEntityManager = aEntityManager;
}
//___________________________________________________________
/**
* Constructor
*
* @param aEntityManager
* @param aTimeoutInSecs
* @param aJoinExistingTransaction
*/
public SeamManualTransaction(EntityManager aEntityManager, int aTimeoutInSecs, boolean aJoinExistingTransaction) {
setTransactionTimeout(aTimeoutInSecs);
fJoinExistingTransaction = aJoinExistingTransaction;
fEntityManager = aEntityManager;
}
//___________________________________________________________
/**
* Starts the new transaction
*
* @throws Exception
*/
public void begin() throws Exception {
if (fObjectUsed) {
throw new Exception(
SeamManualTransaction.class.getCanonicalName() +
" has been used. Create new instance."
);
}
fUserTx =
(UserTransaction) org.jboss.seam.Component.getInstance("org.jboss.seam.transaction.transaction");
fUserTx.setTransactionTimeout(fTransactionTimeout);
fUserTx.begin();
/* If entity manager is created before the transaction
* is started (ie. via Injection) then it must join the
* transaction
*/
if (fJoinExistingTransaction) {
fEntityManager.joinTransaction();
}
}
//___________________________________________________________
/**
* Commit the transaction to the database
*
* @throws Exception
*/
public void commit() throws Exception {
fObjectUsed = true;
fUserTx.commit();
}
// ___________________________________________________________
/ ** *回滚交易 * * @throws Exception * /
public void rollback（）抛出Exception { fObjectUsed = true; fUserTx.rollback（）; }
// ___________________________________________________________ }
答案 0 :(得分：0)
嗯，我的第一个建议是
如果您使用的是EJB应用程序，则更喜欢使用 Bean管理事务而不是自定义 SeamManualTransaction 。当您使用Bean管理事务时，作为开发人员，您负责调用begin和commit。您可以使用UserTransaction组件获得此功能。您可以创建一个Facade图层来开始并提交您的交易。像
这样的东西
/**
* default scope when using @Stateless session bean is ScopeType.STATELESS
*
* So you do not need to declare @Scope(ScopeType.STATELESS) anymore
*
* A session bean can not use both BEAN and CONTAINER Transaction management at The same Time
*/
@Stateless
@Name("businessFacade")
@TransactionManagement(TransactionManagerType.BEAN)
public class BusinessFacade implements BusinessFacadeLocal {
private @Resource TimerService timerService;
private @Resource UserTransaction userTransaction;
/**
* You can use @In of you are using Seam capabilities
*/
private @PersistenceContext entityManager;
public void doSomething() {
try {
userTransaction.begin();
userTransaction.setTransactionTimeout(int seconds);
// business logic goes here
/**
* To enable your Timer service, just call
*
* timerService.createTimer(15*60*1000, 15*60*1000, <ANY_SERIALIZABLE_INFO_GOES_HERE>);
*/
userTransaction.commit();
} catch (Exception e) {
userTransaction.rollback();
}
}
@Timeout
public void doTimer(Timer timer) {
try {
userTransaction.begin();
timer.getInfo();
// logic goes here
userTransaction.commit();
} catch (Exception e) {
userTransaction.rollback();
}
}
}
让我们看看UserTransaction.begin方法API
创建新交易，将其与当前线程相关联
还有更多：
容器管理的持久化上下文的生命周期（通过@PersistenceContext注释注入）对应到事务的范围（在begin和commit方法调用之间）在使用事务范围的持久性时上下文
现在让我们看看TimerService
这是一个容器提供的服务，允许注册企业bean 定时器回调方法在指定的时间，指定的经过时间后或指定的时间间隔后发生。使用计时器的企业bean 的bean类 service必须提供超时回调方法。可以为无状态会话bean，消息驱动的bean
创建计时器
我希望它对你有用
答案 1 :(得分：0)
通常，在范围APPLICATION的Seam组件中注入entityManager是不对的。实体管理器是您在通常比APPLICATION范围短得多的范围内创建，使用和再次关闭的实体管理器。
通过使用标准的entityManager注入选择较小的范围来改进，或者如果您需要APPLICATION范围，请注入EntityManagerFactory，并自己创建，使用和关闭entityManager。
查看Seam components.xml以查找EntityManagerFactory组件的名称。