Spring-如何将Hibernate数据保存到SQL Server? [英] Spring - How to save Hibernate data to SQL server?

问题描述

我正在使用Hibernate开发Spring应用程序.我想保存数据，以便即使在启动和停止服务器时也能保留数据.尝试将数据保存到SQL数据库时，我遇到了很多异常，因此我尝试将Person的实例保存到SQL数据库中，剥离了所有内容，并整理了一个简单的hello世界风格示例.

I'm working on a Spring application with Hibernate. I'd like to save the data so that it persists even when starting and stopping the server. When attempting to save data to an SQL database, I run into a ton of exceptions so I stripped everything back and put together a simple, hello world style example by attempting to save an instance of a Person to the SQL database.

我遍历了所有可以找到的线程，但是它们都与关系有关-这只是一个没有关系的实体.任何建议，不胜感激！

I've been through every thread I can find but they're all relating to relationships - this is just a single entity with no relationships. Any advice greatly appreciated!

这是我保存条目的尝试:

Here's my attempt at saving an entry:

Person person = new Person("Some Person");
personRepository.save(person);
SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(person);
session.getTransaction().commit();

例外:

Caused by: org.hibernate.property.access.spi.PropertyAccessException:
Error accessing field [private java.lang.String com.wdw.core.Person.name] by reflection for persistent property [com.wdw.core.Person#name] : com.wdw.core.Person@4a232870
Caused by: java.lang.IllegalArgumentException: Can not set java.lang.String field com.wdw.core.Person.name to com.wdw.core.Person

型号:

@Entity
public class Person {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private long personId;
    private String name;

    public Person() {
    }

    public Person(String name) {
        this.name = name;
    }

    // getters and setters
}

存储库:

public interface PersonRepository  extends CrudRepository<Person, Long> {}

hibernate.cfg.xml:

hibernate.cfg.xml:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <property name="hibernate.bytecode.use_reflection_optimizer">true</property>
        <property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driver</property>
        <property name="hibernate.connection.password">root</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:8889/the_sideline</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
        <property name="show_sql">true</property>
        <property name="format_sql">true</property>
        <property name="use_sql_comments">true</property>
        <property name="hbm2ddl.auto">create</property>
        <mapping class="com.wdw.core.Person"/>
    </session-factory>
</hibernate-configuration>

当我创建一个没有表的空数据库并运行该程序时，它将创建一个没有条目的表Person:

When I create an empty database with no tables and run the program, it creates the table Person with no entries:

mysql> use test_1
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+---------------------------+
| Tables_in_test_1
+---------------------------+
| Person                    |
+---------------------------+
1 row in set (0.00 sec)

mysql> select * from Person;
Empty set (0.00 sec)

推荐答案

我在这里要做的就是在启动和停止服务器之间保留数据，并能够通过SQL数据库访问数据.通过仅指定要让Hibernate使用的数据库，我无需使用@Transactional或Session接口就解决了该问题.在在此处找到-感谢@Master Slave.

All I wanted to do here was persist the data between starting and stopping the server, and be able to access the data via an SQL database. I solved the issue without using @Transactional or the Session interface, by just specifying the database you want Hibernate to use. Found here - thank you to @Master Slave.

步骤:

1. 启动我的SQL服务器并创建数据库
2. 添加application.properties文件以将Spring配置为使用该数据库
3. 第一次运行应用程序时，将spring.jpa.hibernate.ddl-auto =设置为create.下次，将其设置为update.这将在会话之间保留该数据.

1. Spin up a my SQL server and create a database
2. Add an application.properties file to configure Spring to use that database
3. The first time you run the app, set spring.jpa.hibernate.ddl-auto = to create. The next time, set it to update. This will persist that data across sessions.

application.properties:-仅用于首次运行:

spring.datasource.url=jdbc:mysql://localhost:8889/my_db
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=create

在bootRun之后，将在my_db中填充数据.停止Spring服务器并重新启动它，但这一次是application.properties中的spring.jpa.hibernate.ddl-auto=update.

After bootRun, my_db will be populated with data. Stop your Spring server and restart it, but this time with spring.jpa.hibernate.ddl-auto=update in your application.properties.

希望这可以帮助遇到类似问题的其他人.

Hope this helps somebody else who runs into similar issues.

这篇关于Spring-如何将Hibernate数据保存到SQL Server?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！