springboot simple （9） springboot jpa（Hibernate）

绝地灬酷狼 2024-03-31 10:29 62阅读 0赞

## 1 JPA Hibernate ##

Hibernate是一个全自动的ORM框架（Object Relational Mapping ,对象关系映射）。  
Spring Data JPA：  
是Spring Data的子模块，JPA默认使用hibernate作为ORM实现。

## 2 springboot集成Hibernate ##

第1步：引入pom文件：

<dependency>
    			<groupId>mysql</groupId>
    			<artifactId>mysql-connector-java</artifactId>
    			<version>${mysql-connector}</version>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-data-jpa</artifactId>
    		</dependency>

第2步：定义配置文件：

@Order(Ordered.HIGHEST_PRECEDENCE)
    @Configuration
    @EnableTransactionManagement(proxyTargetClass = true)
    @EnableJpaRepositories(basePackages = "org.feidao.chapter42.repository")
    @EntityScan(basePackages = "org.feidao.chapter42.entity")
    public class JpaConfiguration {
        
        @Bean
        PersistenceExceptionTranslationPostProcessor persistenceExceptionTranslationPostProcessor() {
        
            return new PersistenceExceptionTranslationPostProcessor();
        }
    }

第3步：定义entity实体bean；

@Getter@Setter
    @Entity
    @Table(name="tb_heroic")
    public class Heroic{
        
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        public Long id;
        @Column(name="name")
        public String name = "";
        @Column(name="remarks")
        public String remarks = "";
    }

第4步：定义dao的interface；

@Repository
    public interface HeroicRepository  extends JpaRepository <Heroic, Long>{
        
    }

然后就可以直接调用HeroicRepository 的接口了。

## 3 测试验证 ##

### 3.1 新增英雄(heroic)验证 ###

![在这里插入图片描述][7774ab8bb0e54c379bee2f451f376d9f.png]  
可以数据库中多了一条记录：![在这里插入图片描述][e6ac208a43a44909a8a4483ded6e462b.png]

### 3.2 查询英雄(heroic)验证 ###

![在这里插入图片描述][dccc663d42db414c82a7a25508250875.png]

### 3.3 修改英雄(heroic)验证 ###

![在这里插入图片描述][df1d3afd71b645c98377738a0894738e.png]  
可以数据库记录已经修改  
![在这里插入图片描述][4db641fd9a05462a94f283bdbcf74446.png]

### 3.4 删除英雄(heroic)验证 ###

![在这里插入图片描述][aa08a4395fa544589277ebfd5fde2672.png]  
可见数据库中的记录已经清空了。  
![在这里插入图片描述][0dd34bc6e76844c8bae8fae95b288e33.png]

## 4 问题汇总 ##

**报错1**：org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘entityManagerFactory’  
解决： import org.springframework.data.annotation.Id; 改为improt javax.persistence.Id;

**报错2:**：Caused by: java.lang.NullPointerException  
at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:2997)  
解决：

<dependency>
       <groupId>mysql</groupId>
       <artifactId>mysql-connector-java</artifactId>
       <version>5.1.39</version>
    </dependency>

修改为：

<dependency>
       <groupId>mysql</groupId>
       <artifactId>mysql-connector-java</artifactId>
       <version>8.0.30</version>
    </dependency>

**报错3：**  
com.mysql.cj.exceptions.ConnectionIsClosedException: No operations allowed after connection closed.  
at sun.reflect.GeneratedConstructorAccessor50.newInstance(Unknown Source) ~\[na:na\]  
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~\[na:1.8.0\_25\]  
at java.lang.reflect.Constructor.newInstance(Constructor.java:408) ~\[na:1.8.0\_25\]  
解决：  
配置文件增加：

spring.datasource.hikari.max-lifetime=30000

代码详见：  
[https://gitee.com/linghufeixia/springboot-simple][https_gitee.com_linghufeixia_springboot-simple]  
chapter4-2

--------------------

**教程列表**：  
[springboot simple（0） springboot简介][springboot simple_0_ springboot]

[springboot simple（1） springboot Helloworld][springboot simple_1_ springboot Helloworld]

[springboot simple（2） springboot Starter][springboot simple_2_ springboot Starter]

[springboot simple（3 ）springboot Web开发][springboot simple_3 _springboot Web]

[springboot simple（4）springboot 数据持久化][springboot simple_4_springboot]

[springboot simple （5） springboot Nosql][springboot simple _5_ springboot Nosql]

[springboot simple （6） springboot mqtt][springboot simple _6_ springboot mqtt]

[springboot simple （7） springboot thrift][springboot simple _7_ springboot thrift]

[springboot simple （8） springboot kafka][springboot simple _8_ springboot kafka]

[springboot simple （9） springboot jpa（Hibernate）][springboot simple _9_ springboot jpa_Hibernate]

[springboot simple （10） springboot protobuf][springboot simple _10_ springboot protobuf]

[springboot simple （11） springboot protostuff][springboot simple _11_ springboot protostuff]

[7774ab8bb0e54c379bee2f451f376d9f.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/ae1c0bf3334f4eef98fac8bae0330cb7.png
[e6ac208a43a44909a8a4483ded6e462b.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/b46f0c3b186647689657b7c6586a6329.png
[dccc663d42db414c82a7a25508250875.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/1f7e77124ceb43cca43727275104c3e9.png
[df1d3afd71b645c98377738a0894738e.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/c2cae727c2294e7aaa30c5d9225737ce.png
[4db641fd9a05462a94f283bdbcf74446.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/f2d9e31f7268456197b1f5cc59a8af76.png
[aa08a4395fa544589277ebfd5fde2672.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/d8a3af4397dc4b43a5769e3a4d022022.png
[0dd34bc6e76844c8bae8fae95b288e33.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/31/29b7084f7f7448ad86cd47241c61e31d.png
[https_gitee.com_linghufeixia_springboot-simple]: https://gitee.com/linghufeixia/springboot-simple
[springboot simple_0_ springboot]: https://blog.csdn.net/afei8080/article/details/101297868
[springboot simple_1_ springboot Helloworld]: https://blog.csdn.net/afei8080/article/details/101345712
[springboot simple_2_ springboot Starter]: https://blog.csdn.net/afei8080/article/details/101346285
[springboot simple_3 _springboot Web]: https://blog.csdn.net/afei8080/article/details/101348597
[springboot simple_4_springboot]: https://blog.csdn.net/afei8080/article/details/101422030
[springboot simple _5_ springboot Nosql]: https://blog.csdn.net/afei8080/article/details/101422594
[springboot simple _6_ springboot mqtt]: https://blog.csdn.net/afei8080/article/details/121513387?spm=1001.2014.3001.5502
[springboot simple _7_ springboot thrift]: https://blog.csdn.net/afei8080/article/details/127687148
[springboot simple _8_ springboot kafka]: https://blog.csdn.net/afei8080/article/details/127749475
[springboot simple _9_ springboot jpa_Hibernate]: https://blog.csdn.net/afei8080/article/details/128001389
[springboot simple _10_ springboot protobuf]: https://blog.csdn.net/afei8080/article/details/128297408
[springboot simple _11_ springboot protostuff]: https://blog.csdn.net/afei8080/article/details/128342603