我无法将EntityManager连接到javaFX

// 示例代码：配置数据源
Properties props = new Properties();
props.put("javax.persistence.jdbc.url", "jdbc:mysql://localhost:3306/mydatabase");
props.put("javax.persistence.jdbc.user", "username");
props.put("javax.persistence.jdbc.password", "password");
props.put("javax.persistence.jdbc.driver", "com.mysql.cj.jdbc.Driver");

EntityManagerFactory emf = Persistence.createEntityManagerFactory("myPersistenceUnit", props);
EntityManager em = emf.createEntityManager();

<!-- 示例代码：persistence.xml -->
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence" version="2.1">
    <persistence-unit name="myPersistenceUnit">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <class>com.example.MyEntity</class>
        <properties>
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/mydatabase"/>
            <property name="javax.persistence.jdbc.user" value="username"/>
            <property name="javax.persistence.jdbc.password" value="password"/>
            <property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver"/>
        </properties>
    </persistence-unit>
</persistence>

// 示例代码：事务管理
EntityTransaction tx = em.getTransaction();
try {
    tx.begin();
    // 执行数据库操作
    tx.commit();
} catch (Exception e) {
    if (tx != null && tx.isActive()) {
        tx.rollback();
    }
    throw e;
}