问题
I would like to know if anyone else has used hibernate-envers with mysql in a Spring-boot application using the interface CrudRepository and has had trouble deleting entities with collections. I put together an example application with a test that demonstrates the exception that is generated.
The example can be cloned from https://github.com/LindesRoets/test-delete.git
You will need mysql running with a database called test_delete
CREATE DATABASE IF NOT EXISTS `test_delete` DEFAULT CHARACTER SET utf8;
Run the test
mvn test
You should see the following exception:
2015-08-11 21:36:28.725 ERROR 3855 --- [ main] org.hibernate.AssertionFailure : HHH000099: an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session): java.lang.NullPointerException
Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 4.926 sec <<< FAILURE! - in com.dcp.test.AuthorRepositoryTest
testAuthorCRUD(com.dcp.test.AuthorRepositoryTest) Time elapsed: 0.163 sec <<< ERROR!
org.springframework.transaction.TransactionSystemException: Could not commit JPA transaction; nested exception is javax.persistence.RollbackException: Error while committing the transaction
at org.hibernate.engine.internal.StatefulPersistenceContext.getLoadedCollectionOwnerOrNull(StatefulPersistenceContext.java:756)
at org.hibernate.event.spi.AbstractCollectionEvent.getLoadedOwnerOrNull(AbstractCollectionEvent.java:75)
at org.hibernate.event.spi.InitializeCollectionEvent.<init>(InitializeCollectionEvent.java:36)
at org.hibernate.internal.SessionImpl.initializeCollection(SessionImpl.java:1931)
at org.hibernate.collection.internal.AbstractPersistentCollection$4.doWork(AbstractPersistentCollection.java:558)
at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:260)
at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:554)
at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:142)
at org.hibernate.collection.internal.PersistentBag.iterator(PersistentBag.java:294)
at java.util.AbstractCollection.addAll(AbstractCollection.java:343)
at org.hibernate.envers.internal.entities.mapper.relation.AbstractCollectionMapper.mapCollectionChanges(AbstractCollectionMapper.java:162)
at org.hibernate.envers.internal.entities.mapper.relation.AbstractCollectionMapper.mapModifiedFlagsToMapFromEntity(AbstractCollectionMapper.java:212)
at org.hibernate.envers.internal.entities.mapper.MultiPropertyMapper.map(MultiPropertyMapper.java:105)
at org.hibernate.envers.internal.synchronization.work.DelWorkUnit.generateData(DelWorkUnit.java:66)
at org.hibernate.envers.internal.synchronization.work.AbstractAuditWorkUnit.perform(AbstractAuditWorkUnit.java:76)
at org.hibernate.envers.internal.synchronization.AuditProcess.executeInSession(AuditProcess.java:119)
Below is all the source code as it appears in the sample application.
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>com.test</groupId>
<artifactId>test</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>test-delete</name>
<description></description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.2.5.RELEASE</version>
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<start-class>com.test.Application</start-class>
<java.version>1.8</java.version>
<spring-boot-version>1.2.5.RELEASE</spring-boot-version>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.18.1</version>
<configuration>
<includes>
<include>**/*Test*.java</include>
</includes>
</configuration>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-javadoc-plugin</artifactId>
<version>2.10.3</version>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>${spring-boot-version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>${spring-boot-version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
<version>${spring-boot-version}</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.35</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-envers</artifactId>
</dependency>
</dependencies>
</project>
application.properties
spring.datasource.url = jdbc:mysql://localhost:3306/test_delete
spring.datasource.username =
spring.datasource.password =
# Specify the DBMS
spring.jpa.database = MYSQL
spring.datasource.driverClassName = com.mysql.jdbc.Driver
# Show or not log for each sql query
spring.jpa.show-sql = true
spring.jpa.hibernate.ddl-auto = create
# Naming strategy
spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect
#envers
spring.jpa.properties.org.hibernate.envers.global_with_modified_flag=true
spring.jpa.properties.org.hibernate.envers.store_data_at_delete=true
Application.java
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
BaseEntity.java
@MappedSuperclass
@Audited
public abstract class BaseEntity implements Serializable {
@GeneratedValue(generator = "guid")
@GenericGenerator(name = "guid", strategy = "guid")
@Column(columnDefinition = "CHAR(36)")
@Id
protected String id;
@Temporal(TemporalType.TIMESTAMP)
protected Date dateCreated = new Date();
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public Date getDateCreated() {
return dateCreated;
}
public void setDateCreated(Date dateCreated) {
this.dateCreated = dateCreated;
}
private static final long serialVersionUID = -8371628134270930829L;
}
Author.java
@Entity
@Audited
public class Author extends BaseEntity{
private String email;
private String name;
@OneToMany(mappedBy = "author")
private List<Book> books = new ArrayList<>();
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<Book> getBooks() {
return books;
}
public void setBooks(List<Book> books) {
this.books = books;
}
}
Book.java
@Entity
@Audited
public class Book extends BaseEntity {
private String title;
private String genre;
@ManyToOne
private Author author;
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getGenre() {
return genre;
}
public void setGenre(String genre) {
this.genre = genre;
}
public Author getAuthor() {
return author;
}
public void setAuthor(Author author) {
this.author = author;
}
}
AuthorRepository.java
@Transactional
public interface AuthorRepository extends CrudRepository<Author, String> {
}
AuthorRepositoryTest.java
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = Application.class)
public class AuthorRepositoryTest {
@Autowired
private AuthorRepository authorRepo;
@Test
public void testAuthorCRUD() {
Author author = new Author();
author.setName("Test Name");
author.setEmail("test@mail.com");
Author savedAuthor = authorRepo.save(author);
Assert.assertNotNull(savedAuthor);
authorRepo.delete(savedAuthor);
}
}
If you comment out the @Audited from the entity classes Book, Author and BaseEntity the test pass just fine.
Does anyone know how to make the delete functionality work with envers?
回答1:
There are two ways that I found through trial and error to make the delete operation work as specified in the problem.
You can either specify the collection to load eagerly
@OneToMany(mappedBy = "author", fetch = FetchType.EAGER)
Or you can cascade the delete operation
@OneToMany(mappedBy = "author", cascade = CascadeType.REMOVE)
This is the minimum configuration that you will need to make the test pass as specified in the problem.
来源：https://stackoverflow.com/questions/31954879/hibernate-envers-throwing-exception-when-deleting-entity-with-a-collection-using