java-OpenJPA在没有persistence.xml的代码中使用属性创建EntityManager

我需要在没有persistence.xml的代码中创建EntityManager …
我有

props.put("openjpa.ConnectionURL", "jdbc:sqlserver://databasehost:3306; DatabaseName=dbname; selectMethod=cursor;create=true");
    props.put("openjpa.ConnectionDriverName","com.mysql.jdbc.Driver");
    props.put("openjpa.ConnectionUserName", "dbname");
    props.put("openjpa.ConnectionPassword", "password");
    props.put("openjpa.jdbc.SynchronizeMappings", "buildSchema");
    props.put("openjpa.Log", "DefaultLevel=WARN, Runtime=INFO, Tool=INFO, SQL=TRACE");
    props.put("openjpa.RuntimeUnenhancedClasses", "supported");

    EntityManagerFactory factory = Persistence.createEntityManagerFactory("wp");
    em = factory.createEntityManager(props);

..and当em = factory.createEntityManager(props)被调用时,我得到：

javax.persistence.PersistenceException: No persistence providers available for "wp" after trying the following discovered implementations: org.apache.openjpa.persistence.PersistenceProviderImpl
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:182)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:72)
    at dao.wp.WP_EMH.getCurrentEntityManager(WP_EMH.java:27)

我了解没有提及以tag表示的persistence.xml中的某些内容

PROVIDER- org.apache.openjpa.persistence.PersistenceProviderImpl-/ PROVIDER

我应该如何将其添加到属性？或如何解决？
我的第二个问题是,在persistence.xml中添加了实体类.如何用属性解决这个问题？

谢谢

解决方法:

方法

javax.persistence.Persistence.createEntityManagerFactory(
    String persistenceUnitName);

需要来自persistence.xml的配置.尝试提供您的物业地图给

javax.persistence.Persistence.createEntityManagerFactory(
    String persistenceUnitName, Map properties);

显然,属性集是不完整的.它缺少例如持久性类名：

properties.put("openjpa.MetaDataFactory", "jpa(Types=FQN.class1;FQN.class2;...)");

标签：openjpa,persistence,entitymanager,java
来源： https://codeday.me/bug/20191207/2087084.html