springboot中使用hibernate拦截器的问题

Question

我想在 Spring Boot 中使用 hibernate 拦截器，以便在事务提交后使用afterTransactionCompletion()方法做一些事情。

我按照如何在 Spring Boot 中使用 Spring 管理的 Hibernate 拦截器进行配置（我只是在application.properties添加spring.jpa.properties.hibernate.ejb.interceptor=com.lc.demo.inteceptor.MyInteceptor ）

拦截器可以工作，但是当我尝试在方法afterTransactionCompletion()获取事务状态时仍然存在问题，它始终为NOT_ACTIVE （我希望它可以是COMMITTED ）：

import static org.hibernate.resource.transaction.spi.TransactionStatus.COMMITTED;

import org.hibernate.EmptyInterceptor;
import org.hibernate.Transaction;
import org.hibernate.resource.transaction.spi.TransactionStatus;
import org.springframework.stereotype.Component;


@Component
public class MyInteceptor extends EmptyInterceptor{

    private static final long serialVersionUID = -7992825362361127331L;

    @Override
    public void afterTransactionCompletion(Transaction tx) {
        //The status is always NOT_ACTIVE
        TransactionStatus status = tx.getStatus(); //
        if (tx.getStatus() == COMMITTED) {
            System.out.println("This is what I want to do");
        } else {
            System.out.println("This is what I do not want");
        }
    }

    @Override
    public void beforeTransactionCompletion(Transaction tx) {
        // The status is ACTIVE
        TransactionStatus status = tx.getStatus();
        System.out.println(status);
    }
}

我尝试调试它afterTransactionCompletion()现在调用afterTransactionCompletion()之前，

在扩展AbstractLogicalConnectionImplementor org.hibernate.resource.jdbc.internal.LogicalConnectionProvidedImpl中， commit()方法调用afterCompletion()方法调用resetConnection(boolean initiallyAutoCommit)来设置事务状态NOT_ACTIVE ：

    /*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.resource.jdbc.internal;

import java.sql.Connection;
import java.sql.SQLException;

import org.hibernate.TransactionException;
import org.hibernate.resource.jdbc.ResourceRegistry;
import org.hibernate.resource.jdbc.spi.LogicalConnectionImplementor;
import org.hibernate.resource.jdbc.spi.PhysicalJdbcTransaction;
import org.hibernate.resource.transaction.spi.TransactionStatus;

import org.jboss.logging.Logger;

/**
 * @author Steve Ebersole
 */
public abstract class AbstractLogicalConnectionImplementor implements LogicalConnectionImplementor, PhysicalJdbcTransaction {
    private static final Logger log = Logger.getLogger( AbstractLogicalConnectionImplementor.class );

    private TransactionStatus status = TransactionStatus.NOT_ACTIVE;
    protected ResourceRegistry resourceRegistry;

    @Override
    public PhysicalJdbcTransaction getPhysicalJdbcTransaction() {
        errorIfClosed();
        return this;
    }

    protected void errorIfClosed() {
        if ( !isOpen() ) {
            throw new IllegalStateException( this.toString() + " is closed" );
        }
    }

    @Override
    public ResourceRegistry getResourceRegistry() {
        return resourceRegistry;
    }

    @Override
    public void afterStatement() {
        log.trace( "LogicalConnection#afterStatement" );
    }

    @Override
    public void afterTransaction() {
        log.trace( "LogicalConnection#afterTransaction" );

        resourceRegistry.releaseResources();
    }

    // PhysicalJdbcTransaction impl ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    protected abstract Connection getConnectionForTransactionManagement();

    @Override
    public void begin() {
        try {
            if ( !doConnectionsFromProviderHaveAutoCommitDisabled() ) {
                log.trace( "Preparing to begin transaction via JDBC Connection.setAutoCommit(false)" );
                getConnectionForTransactionManagement().setAutoCommit( false );
                log.trace( "Transaction begun via JDBC Connection.setAutoCommit(false)" );
            }
            status = TransactionStatus.ACTIVE;
        }
        catch( SQLException e ) {
            throw new TransactionException( "JDBC begin transaction failed: ", e );
        }
    }

    @Override
    public void commit() {
        try {
            log.trace( "Preparing to commit transaction via JDBC Connection.commit()" );
            getConnectionForTransactionManagement().commit();
            status = TransactionStatus.COMMITTED;
            log.trace( "Transaction committed via JDBC Connection.commit()" );
        }
        catch( SQLException e ) {
            status = TransactionStatus.FAILED_COMMIT;
            throw new TransactionException( "Unable to commit against JDBC Connection", e );
        }

        afterCompletion();
    }

    protected void afterCompletion() {
        // by default, nothing to do
    }

    protected void resetConnection(boolean initiallyAutoCommit) {
        try {
            if ( initiallyAutoCommit ) {
                log.trace( "re-enabling auto-commit on JDBC Connection after completion of JDBC-based transaction" );
                getConnectionForTransactionManagement().setAutoCommit( true );
                status = TransactionStatus.NOT_ACTIVE;
            }
        }
        catch ( Exception e ) {
            log.debug(
                    "Could not re-enable auto-commit on JDBC Connection after completion of JDBC-based transaction : " + e
            );
        }
    }

    @Override
    public void rollback() {
        try {
            log.trace( "Preparing to rollback transaction via JDBC Connection.rollback()" );
            getConnectionForTransactionManagement().rollback();
            status = TransactionStatus.ROLLED_BACK;
            log.trace( "Transaction rolled-back via JDBC Connection.rollback()" );
        }
        catch( SQLException e ) {
            status = TransactionStatus.FAILED_ROLLBACK;
            throw new TransactionException( "Unable to rollback against JDBC Connection", e );
        }

        afterCompletion();
    }

    protected static boolean determineInitialAutoCommitMode(Connection providedConnection) {
        try {
            return providedConnection.getAutoCommit();
        }
        catch (SQLException e) {
            log.debug( "Unable to ascertain initial auto-commit state of provided connection; assuming auto-commit" );
            return true;
        }
    }

    @Override
    public TransactionStatus getStatus(){
        return status;
    }

    protected boolean doConnectionsFromProviderHaveAutoCommitDisabled() {
        return false;
    }
}

有人可以帮我解决这个问题吗？ 非常感谢。 这是我的pom.xml ：

    <?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.lc</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.10</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

Answer 1

如果您使用的是Spring事务，则可以利用TransactionSynchronization并使用afterCommit()

默认void afterCommit（）

事务提交后调用。 成功完成主要交易后，可以立即执行进一步的操作。

用法：

TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronization(){
           void afterCommit(){
                //do your thing
           }
})

您还可以探索TransactionSynchronizationAdapter以类似的方式可以实现自己的“ AfterCommitExecutor”，该实现实现Executor接口并扩展TransactionSynchronizationAdapter并覆盖afterCommit()方法。

Answer 2

我使用了hovanessyan的答案，它很有效，现在让我完整地描述一下我在这里所做的事情：

我正在尝试将其他人的代码迁移到springboot，代码使用带有persistence.xml的hibernate和拦截器使用threadlocal存储事务中的所有实体，在提交事务后，选择一个“最佳”实体给用户发送电子邮件，否则不执行任何操作并清除threadlocal，代码为：

    public class MyInterceptor extends EmptyInterceptor {

    private static final long serialVersionUID = -7992825362361127331L;

    //The MyThreadLocal used to store all the entities in a transaction, when the transaction
    //committed, the interceptor will choose the "best" entity to email user
    private static MyThreadLocal myThreadLocal;

    public static void setMyThreadLocal(MyThreadLocal mTL) {
        MyInterceptor.myThreadLocal = mTL;
    }

    @Override
    public void afterTransactionCompletion(Transaction tx) {
        TransactionStatus status = tx.getStatus();
        if (tx.getStatus() == COMMITTED) {
            MyThreadLocal.selectTheBestEntityToEmailUser();
        } else {
            MyThreadLocal.clear();
        }
    }

    @Override
    public void beforeTransactionCompletion(Transaction tx) {
        TransactionStatus status = tx.getStatus();
        MyThreadLocal.beforeTransactionCompletion();
    }

    @Override
    public boolean onSave(Object entity, Serializable id, Object[] state, String[] propertyNames, Type[] types) {
        MyThreadLocal.resourceAdded((Entity) entity);
        return false;
    }

    @Override
    public boolean onFlushDirty(Object entity, Serializable id, Object[] currentState, Object[] previousState, String[] propertyNames, Type[] types) {
        Diff diff = new Diff(previousState, currentState, propertyNames);
        MyThreadLocal.resourceUpdated((Entity) entity, diff);
        return false;
    }

    @Override
    public void onDelete(Object entity, Serializable id, Object[] state, String[] propertyNames, Type[] types) {
        MyThreadLocal.resourceRemoved((Entity) entity);
    }

    @Override
    public void onCollectionUpdate(Object collection, Serializable key) throws CallbackException {
        if (!(collection instanceof PersistentCollection)) {
            LOGGER.e("Unsupported collection type: {}", collection.getClass());
            return;
        }
        Entity owner = (Entity) ((PersistentCollection) collection).getOwner();
        String role = ((PersistentCollection) collection).getRole();
        MyThreadLocal.collectionResourceUpdated(owner, role);
    }
}

但是在afterTransactionCompletion（）方法中，事务状态始终为NOT_ACTIVE，现在我使用TransactionSynchronization接口只是为了替换afterTransactionCompletion（）方法：

    public class MyInterceptor extends EmptyInterceptor implements TransactionSynchronization {

    //the mothod of TransactionSynchronization interface
    @Override
    public void afterCompletion(int status) {
        if (status == STATUS_COMMITTED) {
            MyThreadLocal.selectTheBestEntityToEmailUser();
        } else {
            MyThreadLocal.clear();
        }
    }

    //the old code which works not well
    @Override
    public void afterTransactionCompletion(Transaction tx) {
        TransactionStatus status = tx.getStatus();
        if (tx.getStatus() == COMMITTED) {
            MyThreadLocal.selectTheBestEntityToEmailUser();
        } else {
            MyThreadLocal.clear();
        }
    }

   ...... other codes
}

而且新的接收器还需要由AOP全局配置：

@Component
@Aspect
public class InterceptorInit{
    @Autowired
    private MyInteceptor mI;

    @Before("@annotation(org.springframework.transaction.annotation.Transactional)")
    public void registerTransactionSyncrhonization() {
        TransactionSynchronizationManager.registerSynchronization(mI);
    }
}

现在看来一切正常，我将继续测试。

Answer 3

虽然我也建议使用 Spring TransactionSynchronization。 如果不能使用（或不想使用），有两件事需要注意：

beforeTransactionCompletion - “在提交事务之前（但不在回滚之前）调用。” - 这意味着该方法实际上可用于在提交之前识别事务是否正常，并将其保存在某个临时（理想情况下为 ThreadLocal）状态。

afterTransactionCompletion - 如果事务被回滚，事务的状态不是“NOT_ACTIVE”而是“MARKED_ROLLBACK” - 因此状态“NOT_ACTIVE”与实际调用的 beforeTransactionCompletion 相结合可用于确定事务是否成功。