Question

信息：HHH10001008：清理连接池[jdbc：mysql：// localhost：3306 / hb_student_tracker？useSSL = false＆serverTimezone = UTC] 线程“主” org.hibernate.PropertyAccessException中的异常：无法通过反射设置字段值[POST_INSERT_INDICATOR]的值：[类com.luvjava.hibernate.demo.entity.Student.id]的设置 com.luvjava.hibernate.demo.entity.Student.id位于 org.hibernate.property.access.spi.SetterFieldImpl.set（SetterFieldImpl.java:72）在 com.luvjava.hibernate.demo.CreateStudentDemo.main（CreateStudentDemo.java:33）引起原因：java.lang.IllegalArgumentException：无法设置int字段 com.luvjava.hibernate.demo.entity.Student.id至 org.hibernate.id.IdentifierGeneratorHelper $ 2

将学生对象保存在CreateStudentDemo.class中时，出现

错误

CreateStudentDemo.class

package com.luvjava.hibernate.demo;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

import com.luvjava.hibernate.demo.entity.Student;

public class CreateStudentDemo {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        //create session factory
        SessionFactory factory=new Configuration()
                                   .configure("hibernate.cfg.xml")
                                   .addAnnotatedClass(Student.class)
                                   .buildSessionFactory();

        //create session object
        Session session=factory.getCurrentSession();
        System.out.println("before try block");
        //save object

        try {
            //begin transaction
            session.beginTransaction();
            System.out.println("Creating student object..");
            //create object
            Student theStudent=new Student("Ravisher","Singh","rvsingh3213@gmail.com");
            //save object
            System.out.println("Saving Student Object...");
            session.save(theStudent);  **This is line from where exception starts**
            System.out.println(" afterSaving Student Object...");

            //commit changes
            session.getTransaction().commit();
            System.out.println("commit Done");
        }
        finally {
            session.flush();
            session.close();
            factory.close();
        }

    }

}

这是实体类

package com.luvjava.hibernate.demo.entity;

import java.io.Serializable;

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;


    @Id
    @Column(name="first_Name" )
    private String firstName;

    @Id
    @Column(name="last_Name")
    private String lastName;

    @Id
    @Column(name="email")
    private String email;

    public Student() {
        System.out.println("In default constructor");
    }

    //Constructor using fields
    public Student(String firstName, String lastName, String email) {
        System.out.println("arg constructor.");
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }

    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;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "Student [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + ", email=" + email + "]";
    }




}

这将是hibernate.cfg.xml

<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>

        <!-- JDBC Database connection settings -->
        <property name="connection.driver_class">com.mysql.cj.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost:3306/hb_student_tracker?useSSL=false&amp;serverTimezone=UTC</property>
        <property name="connection.username">hbstudent</property>

        <property name="connection.password">hbstudent</property>

        <!-- JDBC connection pool settings ... using built-in test pool -->
        <property name="connection.pool_size">1</property>

        <!-- Select our SQL dialect -->
        <property name="dialect">org.hibernate.dialect.MySQLDialect</property>

        <!-- Echo the SQL to stdout -->
        <property name="show_sql">true</property>

        <!-- Set the current session context -->
        <property name="current_session_context_class">thread</property>

    </session-factory>

</hibernate-configuration>

Answer 1

您的实体类中仅需要一个@Id注释这是您实体的外观

@Entity
@Table(name="student")
public class Student {

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

    @Column(name="first_Name" ) <--- first_Name, this value MUST MATCH WITH WHAT YOU HAVE IN YOUR DATABASE
    private String firstName;

    @Column(name="last_Name")<--- last_Name, this value MUST MATCH WITH WHAT YOU HAVE IN YOUR DATABASE
    private String lastName;

    @Column(name="email")
    private String email;

    public Student() {
        System.out.println("In default constructor");
    }

    //Constructor using fields
    public Student(String firstName, String lastName, String email) {
        System.out.println("arg constructor.");
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }

    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;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "Student [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + ", email=" + email + "]";
    }




}

无法使用休眠保存对象

1 个答案: