java 在没有持久性文件的情况下以编程方式创建实体管理器

create entity manager programmatically without persistence file

提问by tamtoum1987

I'm trying to create entity Factory manager programmatically without persistence file

我试图在没有持久性文件的情况下以编程方式创建实体工厂管理器

    EntityManagerFactory emf;
    Map<String, String> properties = new HashMap<String, String>();
    properties.put("hibernate.connection.driver_class", "com.mysql.jdbc.Driver");
    properties.put("hibernate.connection.url", "jdbc:mysql://173.194.25***************");
    properties.put("hibernate.connection.username", "etech****");
    properties.put("hibernate.connection.password", "A*****");
    properties.put("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");
    properties.put("hibernate.show-sql", "true");
    properties.put("provider", "org.hibernate.ejb.HibernatePersistence");
    emf = Persistence.createEntityManagerFactory(idClient, properties);

On line

在线的

emf = Persistence.createEntityManagerFactory(idClient, properties);

I am getting the error:

我收到错误：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com****RepositoryFieldsFieldWorkerRepositoryImpl': Invocation of init method failed; nested exception is javax.persistence.PersistenceException: No Persistence provider for EntityManager named idClient

org.springframework.beans.factory.BeanCreationException：创建名为 'com****RepositoryFieldsFieldWorkerRepositoryImpl' 的 bean 时出错：调用 init 方法失败；嵌套异常是 javax.persistence.PersistenceException: No Persistence provider for EntityManager named idClient

How can i resolve this problem ?

我该如何解决这个问题？

any help will be appreciated

任何帮助将不胜感激

回答by Brice

Here is a pure programmatic way to build an entity manager without spring and without a persistence.xml. Constants are taken from org.hibernate.cfg.AvailableSettings:

这是一种纯粹的编程方式来构建没有 spring 和persistence.xml. 常数取自org.hibernate.cfg.AvailableSettings：

entityManagerFactory = new HibernatePersistenceProvider().createContainerEntityManagerFactory(
            archiverPersistenceUnitInfo(),
            ImmutableMap.<String, Object>builder()
                    .put(JPA_JDBC_DRIVER, JDBC_DRIVER)
                    .put(JPA_JDBC_URL, JDBC_URL)
                    .put(DIALECT, Oracle12cDialect.class)
                    .put(HBM2DDL_AUTO, CREATE)
                    .put(SHOW_SQL, false)
                    .put(QUERY_STARTUP_CHECKING, false)
                    .put(GENERATE_STATISTICS, false)
                    .put(USE_REFLECTION_OPTIMIZER, false)
                    .put(USE_SECOND_LEVEL_CACHE, false)
                    .put(USE_QUERY_CACHE, false)
                    .put(USE_STRUCTURED_CACHE, false)
                    .put(STATEMENT_BATCH_SIZE, 20)
                    .build());

entityManager = entityManagerFactory.createEntityManager();

And the infamous PersistenceUnitInfo

还有臭名昭著的 PersistenceUnitInfo

private static PersistenceUnitInfo archiverPersistenceUnitInfo() {
    return new PersistenceUnitInfo() {
        @Override
        public String getPersistenceUnitName() {
            return "ApplicationPersistenceUnit";
        }

        @Override
        public String getPersistenceProviderClassName() {
            return "org.hibernate.jpa.HibernatePersistenceProvider";
        }

        @Override
        public PersistenceUnitTransactionType getTransactionType() {
            return PersistenceUnitTransactionType.RESOURCE_LOCAL;
        }

        @Override
        public DataSource getJtaDataSource() {
            return null;
        }

        @Override
        public DataSource getNonJtaDataSource() {
            return null;
        }

        @Override
        public List<String> getMappingFileNames() {
            return Collections.emptyList();
        }

        @Override
        public List<URL> getJarFileUrls() {
            try {
                return Collections.list(this.getClass()
                                            .getClassLoader()
                                            .getResources(""));
            } catch (IOException e) {
                throw new UncheckedIOException(e);
            }
        }

        @Override
        public URL getPersistenceUnitRootUrl() {
            return null;
        }

        @Override
        public List<String> getManagedClassNames() {
            return Collections.emptyList();
        }

        @Override
        public boolean excludeUnlistedClasses() {
            return false;
        }

        @Override
        public SharedCacheMode getSharedCacheMode() {
            return null;
        }

        @Override
        public ValidationMode getValidationMode() {
            return null;
        }

        @Override
        public Properties getProperties() {
            return new Properties();
        }

        @Override
        public String getPersistenceXMLSchemaVersion() {
            return null;
        }

        @Override
        public ClassLoader getClassLoader() {
            return null;
        }

        @Override
        public void addTransformer(ClassTransformer transformer) {

        }

        @Override
        public ClassLoader getNewTempClassLoader() {
            return null;
        }
    };
}

Note that Spring offers streamlined way to configure the persistence, while supporting multiple hibernate versions. (Spring 4.2 supports Hibernate up to 5.1, Spring 4.3 supports Hibernate up to 5.2).

请注意，Spring 提供了配置持久性的简化方法，同时支持多个休眠版本。（Spring 4.2 最高支持 Hibernate 5.1，Spring 4.3 最高支持 Hibernate 5.2）。

回答by mssch

A persistence.xmlfile is mandatory to create your persistence unit at deployment time as per the JPA specs.

根据persistence.xmlJPA 规范，在部署时创建持久性单元必须有一个文件。

See Create JPA EntityManager without persistence.xml configuration file

请参阅创建没有persistence.xml 配置文件的JPA EntityManager