Question

我是JavaEE的新手，并且很难在Intellij中使用JPA控制台。在执行JPQL查询时浪费了大量时间来消除此错误：

jpa-ql> SELECT p FROM PersonEntity p
[2017-04-21 18:44:46] using C:\Users\admin\.IntelliJIdea2017.1\system\compiler\jpaproject4.0.82b748b3\.generated\Jpa_Console\JpaProject4.0-PU-1492789486636\META-INF\persistence.xml
[2017-04-21 18:44:48] PersonEntity is not mapped [SELECT p FROM PersonEntity p]

我在MySQL中创建了简单的JavaEE Persistence项目和简单的数据库。我在Intellij中添加了DataSource并生成了持久性映射。我导入了必要的库并摆脱了所有编译错误。我可以在数据库工具窗口中看到我的数据库并可以执行SQL查询。但由于这个恼人的错误，我无法执行JPQL查询：PersonEntity未映射。

的persistence.xml：

<persistence-unit name="NewPersistenceUnit">
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
    <class>models.PersonEntity</class>
    <properties>
        <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/sample"/>
        <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
        <property name="hibernate.connection.username" value=""/>
        <property name="hibernate.connection.password" value=""/>
        <property name="hibernate.archive.autodetection" value="class"/>
        <property name="hibernate.show_sql" value="true"/>
        <property name="hibernate.format_sql" value="true"/>
        <property name="hbm2ddl.auto" value="update"/>
    </properties>
</persistence-unit>

PersonEntity.java：

package models;


import javax.persistence.*;

@Entity
@Table(name = "person", schema = "sample", catalog = "")
public class PersonEntity {
    private int id;
    private String name;

    @Id
    @Column(name = "id")
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    @Basic
    @Column(name = "name")
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        PersonEntity that = (PersonEntity) o;

        if (id != that.id) return false;
        if (name != null ? !name.equals(that.name) : that.name != null) return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = id;
        result = 31 * result + (name != null ? name.hashCode() : 0);
        return result;
    }
}

数据库结构： DB structure

项目结构： Project structure

有任何解决此问题的想法吗？

Answer 1

管理自己解决问题。

我通过执行此查询为MySQL数据库中的root用户授予了权限： GRANT ALL PRIVILEGES ON * . * TO 'root'@'localhost'
在我的persistense.xml中，我添加了数据库用户凭据： <property name="hibernate.connection.username" value="dbuser"/> <property name="hibernate.connection.password" value="password"/>
我创建了以编程方式执行JPQL查询的主类：

`

import models.PersonEntity;
import org.hibernate.jpa.HibernatePersistenceProvider;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.spi.PersistenceProvider;
import java.util.HashMap;
import java.util.List;

public class App {
    public static final String QUERY = "SELECT p FROM PersonEntity p";
    public static void main(String[] args) {
        PersistenceProvider persistenceProvider = new HibernatePersistenceProvider();
        EntityManagerFactory factory = persistenceProvider.createEntityManagerFactory("NewPersistenceUnit", new HashMap());
        EntityManager em = factory.createEntityManager();
        List<PersonEntity> resultList = em.createQuery(QUERY, PersonEntity.class).getResultList();
        System.out.println(resultList);
        em.close();
    }
}`

JPA控制台仅在执行主方法后才能工作。在此之前我收到了一个错误：用户访问被拒绝＆＃39; @＆＃39; localhost＆＃39;。

希望它可以帮助您节省时间！

无法在JPA控制台Intellij中执行JPQL查询

1 个答案: