Question

我有一个非常简单的Hibernate设置，但是在保存实体时收到此奇怪的错误：

org.hibernate.property.access.spi.PropertyAccessException：通过反射访问持久性[com.example.demo]字段而错误访问字段[private java.lang.String com.example.demo.Student.firstName]。 Student＃firstName]：学生[id = 0，firstName = My，lastName = Name]

这是我保存它的方式：

StudentDao studentDao = new StudentDao();
Student student = new Student("My", "Name");
studentDao.saveStudent(student);

这是我的学生实体：

package com.example.demo;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "student")
public class Student {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private int id;
    @Column(name = "first_name")
    private String firstName;
    @Column(name = "last_name")
    private String lastName;
    public Student() {
    }
    public Student(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    @Override
    public String toString() {
        return "Student [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + "]";
    }
}

StudentDao：

package com.example.demo;

import java.util.List;
import org.hibernate.Session;
import org.hibernate.Transaction;
import com.example.demo.Student;
import com.example.demo.HibernateUtil;

public class StudentDao {
    public void saveStudent(Student student) {
        Transaction transaction = null;
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            // start a transaction
            transaction = session.beginTransaction();
            // save the student object
            session.save(student);
            // commit transaction
            transaction.commit();
        } catch (Exception e) {
            e.printStackTrace();
            if (transaction != null) {
                transaction.rollback();
            }
        }
    }
    public List <Student> getStudents() {
        try (Session session = HibernateUtil.getSessionFactory().openSession()) {
            return session.createQuery("from Student", Student.class).list();
        }
    }
}

HibernateUtil：

package com.example.demo;

import java.util.Properties;
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.cfg.Environment;
import org.hibernate.service.ServiceRegistry;
import com.example.demo.Student;

public class HibernateUtil {
    private static SessionFactory sessionFactory;
    public static SessionFactory getSessionFactory() {
        if (sessionFactory == null) {
            try {
                Configuration configuration = new Configuration();
                // Hibernate settings equivalent to hibernate.cfg.xml's properties
                Properties settings = new Properties();
                settings.put(Environment.DRIVER, "com.mysql.cj.jdbc.Driver");
                settings.put(Environment.URL, "jdbc:mysql://localhost:3306/hibernate_db?useSSL=false&serverTimezone=UTC");
                settings.put(Environment.USER, "root");
                settings.put(Environment.PASS, "root");
                settings.put(Environment.DIALECT, "org.hibernate.dialect.MySQL5Dialect");
                settings.put(Environment.SHOW_SQL, "true");
                settings.put(Environment.CURRENT_SESSION_CONTEXT_CLASS, "thread");
                settings.put(Environment.HBM2DDL_AUTO, "create-drop");
                configuration.setProperties(settings);
                configuration.addAnnotatedClass(Student.class);
                ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
                        .applySettings(configuration.getProperties()).build();
                sessionFactory = configuration.buildSessionFactory(serviceRegistry);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return sessionFactory;
    }
}

我的依赖项：

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.13</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-core -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.3.7.Final</version>
        </dependency>

我尝试了不同版本的hibernate-core，但没有任何效果。

Answer 1

我正在使用spring框架。删除以下依赖项后，它起作用了：

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-devtools</artifactId>
</dependency>

休眠错误，通过对持久属性的反射来访问字段[private java.lang.String com.example.demo.Student.firstName]

1 个答案: