我使用这样的配置注释创建ThreadPoolTaskExecutor
public class AsyncConfiguration implements AsyncConfigurer, EnvironmentAware {
private final Logger log = LoggerFactory.getLogger(AsyncConfiguration.class);
private RelaxedPropertyResolver propertyResolver;
@Override
public void setEnvironment(Environment environment) {
this.propertyResolver = new RelaxedPropertyResolver(environment, "async.");
}
@Override
@Bean
public Executor getAsyncExecutor() {
log.debug("Creating Async Task Executor");
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setCorePoolSize(propertyResolver.getProperty("corePoolSize", Integer.class, 30));
executor.setMaxPoolSize(propertyResolver.getProperty("maxPoolSize", Integer.class, 150));
executor.setQueueCapacity(propertyResolver.getProperty("queueCapacity", Integer.class, 10000));
executor.setThreadNamePrefix("app-Executor-");
return new ExceptionHandlingAsyncTaskExecutor(executor);
}
@Override
public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
return new SimpleAsyncUncaughtExceptionHandler();
}
}
我在此类中使用ThreadPoolExecutor
@Component
public class TrapReceiver extends Thread implements CommandResponder {
@Inject
private ApplicationContext applicationContext;
@Inject
private Executor executor;
public TrapReceiver(){
}
List<PDUv1> listPdu = new ArrayList<PDUv1>();
@PostConstruct
public void init() {
this.start();
}
public synchronized void processPdu(CommandResponderEvent cmdRespEvent) {
PDUv1 pdu = (PDUv1) cmdRespEvent.getPDU();
listPdu.add(pdu);
if (pdu != null) {
if(listPdu.size() == 3){ //3 pdu per thread
List<PDUv1> temp = new ArrayList<PDUv1>();
temp.addAll(listPdu);
TrapInsertor trapInsertor = (TrapInsertor) applicationContext.getBean("trapInsertor");
trapInsertor.setProperty(temp);
executor.execute(trapInsertor);
listPdu.clear();
}
}
}
这是我的线程类
public class TrapInsertor implements Runnable {
@Inject
private TrapProcessorService trapProcessorService;
private List<PDUv1> listPdu;
public void setProperty(List<PDUv1> listPdu){
this.listPdu = listPdu;
}
@Override
public void run() {
try{
System.out.println(Thread.currentThread().getName()+" Start process "+listPdu.size()+" PDU");
for(PDUv1 pdu : listPdu){
String[] varBinding = pdu.getVariableBindings().toString().replace("[", "").replace("]", "").split(", ");
trapProcessorService.processTrap(varBinding);
}
listPdu.clear();
}catch (Exception e) {
e.printStackTrace();
}finally{
}
}
}
但是有时候我会出现这样的错误
java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:859)
at java.util.ArrayList$Itr.next(ArrayList.java:831)
at app.snmp.test.TrapInsertor.run(TrapInsertor.java:37)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
也这样
org.springframework.dao.CannotAcquireLockException: could not execute statement; SQL [n/a]; nested exception is org.hibernate.exception.LockAcquisitionException: could not execute statement
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:239)
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:214)
at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:521)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:757)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:726)
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:497)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:277)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653)
at app.snmp.test.service.TrapProcessorService$$EnhancerBySpringCGLIB$$3d040253.processTrap(<generated>)
at app.snmp.test.TrapInsertor.run(TrapInsertor.java:39)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.hibernate.exception.LockAcquisitionException: could not execute statement
at org.hibernate.dialect.MySQLDialect$1.convert(MySQLDialect.java:451)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:126)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:112)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:211)
at org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:62)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3281)
at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:3183)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3525)
at org.hibernate.action.internal.EntityUpdateAction.execute(EntityUpdateAction.java:159)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:463)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:349)
at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:350)
at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:56)
at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1222)
at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:425)
at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.beforeTransactionCommit(JdbcTransaction.java:101)
at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:177)
at org.hibernate.jpa.internal.TransactionImpl.commit(TransactionImpl.java:77)
at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:517)
... 12 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
at com.mysql.jdbc.Util.getInstance(Util.java:360)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:985)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3887)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3823)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2435)
at com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1288)
at com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStatement.java:794)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2141)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2077)
at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2062)
at com.zaxxer.hikari.proxy.PreparedStatementProxy.executeUpdate(PreparedStatementProxy.java:61)
at com.zaxxer.hikari.proxy.PreparedStatementJavassistProxy.executeUpdate(PreparedStatementJavassistProxy.java)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:208)
... 27 more
我的代码有什么问题？如果那个由listPdu集合引起的错误在线程之间共享？
........
通过在此配置类中添加作用域原型，可以解决ConcurrentModificationException错误。原型意味着每次请求时都会创建新的bean实例。感谢@Vladimir Sitnikov
@Configuration
public class TrapProcessorComponentConfiguration {
@Bean
@Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public TrapInsertor trapInsertor(){
return new TrapInsertor();
}
}
最佳答案
问题出在您的弹簧配置中。您可能会重用相同的trapInsertor实例，因此会重用所有例外。
您的“ trapInsertor” bean是单例bean吗？我认为在春季默认情况下，bean是单例的。
看看会发生什么：
您收集了3件物品
调用trapInsertor.setProperty(temp); //表示它是arrayList1
调用executor.execute(trapInsertor);，但是trapInsertor尚未启动（线程池开始工作之前可能需要一段时间）
您再收集3件物品
调用trapInsertor.setProperty(temp); //表示它是arrayList2
致电executor.execute(trapInsertor);
现在，来自＃3和＃6的动作开始起作用。他们可能都看到相同的arrayList2。
因此，您可以拥有：
数据丢失。基本上，根本不处理arrayList1！
一个线程遍历列表for(PDUv1 pdu : listPdu){（在TrapInsertor中），另一个线程执行listPdu.clear()（在TrapInsertor中）。结果为ConcurrentModificationException。
两个线程都可能将数据写入数据库，从而相互锁定，因此MySQLTransactionRollbackException: Deadlock found when trying to get lock;
我建议您重新创建提交给执行者的任务。
换句话说，您需要类似scope="prototype"的内容（请参见How do I force a spring container not to return a singleton instance of a bean?）