java.lang.IllegalArgumentException：未知实体：Jpa

Question

我想通过他id删除一个人，但是报错：

Exception in thread "main" java.lang.IllegalArgumentException: Unknown entity: org.hibernate.query.internal.QueryImpl

在数据库工作中查找实体的方法：

   public class MySQLPersonDAO implements PersonDAO {
     @Override
        public void deleteById(int id) {
            EntityManager em = FACTORY.createEntityManager();
            EntityTransaction transaction = em.getTransaction();
            transaction.begin();
            TypedQuery query = em.createQuery("SELECT p FROM Person p WHERE p.id = :id", Person.class);
            query.setParameter("id", id);
            em.remove(query); // hier mistake
            transaction.commit();
            em.close();
        }

人

@Entity
public class Person {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "person_id")
    private int id;

    private String name;

    private String password;
//getters,setters,constructor

坚持我需要明确指定所有实体吗？

    <persistence-unit name="myjpa">
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <class> com.evghenii.domain.Person</class>
        <properties>
            <property name="hibernate.connection.driver_class" value="com.mysql.cj.jdbc.Driver"/>
            <property name="hibernate.connection.password" value="root"/>
            <property name="hibernate.connection.username" value="root"/>
            <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/board_jpa?serverTimezone=Europe/Berlin"/>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL8Dialect"/>
            <!--<property name="hibernate.hbm2ddl.auto" value="create"/>-->
            <property name="hibernate.hbm2ddl.auto" value="update"/>
            <property name="hibernate.show_sql" value="true"/>
        </properties>
    </persistence-unit>
</persistence>

maven

    <dependencies>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.4.11.Final</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.19</version>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>5.4.12.Final</version>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>6.0.17.Final</version>
        </dependency>       
    </dependencies>

</project>

Answer 1

正如消息所说，remove 想要删除一个 Entity，因此您需要一个持久化的 Person 来执行此操作。与你相处的人

Person person = em.find(Person.class,id);

您使用

执行更新或删除查询

query.executeUpdate();

java.lang.IllegalArgumentException：未知实体：Jpa

java.lang.IllegalArgumentException: Unknown entity: Jpa

java

hibernate

jpa

jpql

illegalargumentexception