hibernate之persistence错误

错误码：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.class]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory

上述错误码nested exception is javax.persistence.PersistenceException可知是实体类实例化的时候报错，所以应该查看实体类是否有注解、字段书写的错误，我的是因为之前做关联，后面去掉了，但注解没有去掉导致，出错代码：

    @NotNull
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "user_id", nullable = false)
    private long userId;

之前是：

    @NotNull
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "user_id", nullable = false)
    private User user;

正确的是：

　　@JoinColumn(name = "user_id", nullable = false)
　　private long userId;