我有一段示例代码:事务回滚永远不会奏效
public class JpaTest {
private EntityManagerFactory emf;
private void setUp() throws Exception {
emf = Persistence.createEntityManagerFactory("testPU");
}
private void tearDown() {
emf.close();
}
private void save() {
EntityManager em = null;
EntityTransaction tx = null;
try {
em = emf.createEntityManager();
tx = em.getTransaction();
tx.begin();
em.persist(new Event("First event", new Date()));
em.persist(new Event("A follow up event", new Date()));
throw new RuntimeException();
} catch (Exception e) {
if (tx != null) tx.rollback();
} finally {
if (em != null) em.close();
}
}
public static void main(String[] args) throws Exception {
JpaTest test = new JpaTest();
test.setUp();
test.save();
test.tearDown();
}
}
的数据库为MySQL。 该代码将Event实体保存到数据库中,并抛出异常。我希望tx.rollback()删除制作成数据库的变化,但是这个命令从来没有工作和数据保留在表:
的问题是,为什么tx.rollback()失败,以及如何如果事务抛出异常,删除数据库中所做的更改?
更新: 的persistence.xml:
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
version="2.1">
<persistence-unit name="testPU">
<class>exampleForTestingJpa.Event</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.url"
value="url here..."/>
<property name="javax.persistence.jdbc.user" value="username here..."/>
<property name="javax.persistence.jdbc.password" value="password here..."/>
<property name="hibernate.show_sql" value="true"/>
<property name="hibernate.hbm2ddl.auto" value="update"/>
<property name="hibernate.connection.autocommit" value="false"/>
</properties>
</persistence-unit>
</persistence>
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>
<groupId>groupId</groupId>
<artifactId>example</artifactId>
<version>1.0-SNAPSHOT</version>
<build>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>4.3.8.RELEASE</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.2.9.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.39</version>
</dependency>
</dependencies>
</project>
我有一个问题。'finally'中的'commit'怎么样?我认为你也需要它 – fg78nc
如果你的JPA提供者真的不回滚一个事务(并且你没有一些奇怪的配置导致这个),那么这是你的JPA提供者中的一个错误。没有JPA提供者应该默认启用“autocommit”,因为它违反了JPA规范 –
试着重建你的项目。显示你的pom.xml请 – fg78nc