spring 全家桶系列之 spring data jpa

女爷i 2021-11-22 07:08 413阅读 0赞

**懒加载失效：[参考][Link 1]**

**常用注解 ：[参考][Link 2]**

**封装JPA基本功能 ：[参考][Link 3]**

**hibernate N+1问题：[参考][Link 4]**

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**使用spring boot 整合 spring data jpa**

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> **maven **

<dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-jpa</artifactId>
            </dependency>
            
            <dependency>
                <groupId>com.fasterxml.jackson.datatype</groupId>
                <artifactId>jackson-datatype-hibernate5</artifactId>
                <version>2.9.9</version>
            </dependency>
             
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql.version}</version>
                <scope>runtime</scope>
            </dependency>

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

>  application配置文件

**一般的话修改方言，database即可**

jpa:
        database: MYSQL
        #在启动时初始化架构
        generate-ddl: true
        #注册OpenEntityManagerInViewInterceptor拦截器
        open-in-view: true
        #hibernate 配置参考 https://docs.jboss.org/hibernate/orm/5.4/userguide/html_single/Hibernate_User_Guide.html#configurations
        hibernate:
          ddl-auto: update
        properties:
          hibernate:
            dialect: org.hibernate.dialect.MySQL8Dialect
            current_session_context_class: org.springframework.orm.hibernate5.SpringSessionContext
            #在给定的事务持久性上下文之外初始化懒加载
            enable_lazy_load_no_trans: true
            #降低高度并发中事务死锁的可能性
            order_inserts: true
            order_updates: true
            jdbc:
              #批量处理 50条新增一次(create，update，delete)
              batch_size: 50
              #版本化实体是否应包含在批处理中
              batch_versioned_data: true
            #使用@Transient注解操作异常问题解决
            event:
              merge:
                entity_copy_observer: allow

> 显示sql语句添加

jpa:
        show-sql: true
        properties:
          hibernate:
            #格式化sql
            format_sql: true
            #Hibernate会在SQL中生成注释便于调试
            use_sql_comments: true

配置完成

[Link 1]: https://blog.csdn.net/qq_37059838/article/details/88414384
[Link 2]: https://blog.csdn.net/qq_37059838/article/details/84400438
[Link 3]: https://blog.csdn.net/qq_37059838/article/details/85004034
[Link 4]: https://docs.jboss.org/hibernate/orm/5.4/userguide/html_single/Hibernate_User_Guide.html#fetching-fetch-annotation