mysql - 无法使用 Spring Hibernate 连接到 MySQL 数据库

Question

我是 Spring 的新手，无法通过 Spring Hibernate 连接到我的 MySQL 数据库。我明白了

Request processing failed; nested exception is : org.springframework.transaction.CannotCreateTransactionException:

Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Could not open connection

我的 applicationContext.xml

<context:annotation-config />
<context:component-scan base-package="Zoostore" />
<tx:annotation-driven />
<bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
    <property name="url" value="jdbc:mysql://localhost:3306/zoostore?characterEncoding=UTF-8"/>
    <property name="username" value="root"/>
    <property name="password" value="your_password"/>
</bean>


<bean id="entityManagerFactory"
      class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
      p:dataSource-ref="dataSource"
      />

<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

<bean id="transactionManager"
      class="org.springframework.orm.jpa.JpaTransactionManager"
      p:entityManagerFactory-ref="entityManagerFactory"
      p:persistenceUnitName="BookJpaPersistenceUnit"/>

<tx:annotation-driven transaction-manager="transactionManager"/>

这是我的 Controller 代码的一部分，我尝试将数据存储到数据库并从中获取数据

@RequestMapping(value = "saveadvert", method = RequestMethod.POST)
public ModelAndView saveAdvert(Advert advert) {
    advert.setUserId(1);
    advertService.persist(advert);
    return new ModelAndView("test", "allAdverts", advertService.getAll());

这是我得到的异常:

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Could not open connection
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

如有必要，我可以提供根本原因

Answer 1

不确定是哪种错误，我提到我遇到的条件。

1. 确保你打开了mysql服务，你可以测试连接IDE数据库功能，比如IDEA。
2. 注意useSSL=false，有时它会是致命的。
3. 如果您的 mysql-connector-java 版本高于 8.*，您可能需要将 datasource-driver-name 更改为 com.mysql.cj.jdbc.Driver

Though spring will help you change.

1. 如果您指定带有表名、列的 jpa。确保使用正确的语法 @Table(name='xxx') @Column(name= 'xxx')
2. 注意 mysql 服务器的端口。

In windows. netstat -ano |findstr: 3306

taskkill /PID enterPID /F

In Linux netstat -anp |grep 3306 kill -9 pid

• 检查 gradle 或 maven 依赖
• 这就是我卡住的地方。

In spring-boot, you can make the configuration set up automatically. But you need to make the files right in their places.

• xx.yml需要放入资源(在IDEA中需要指定包为资源包)
• xxxApplication.class(spring-boot-starter类应该在其他类之外，或者指定其他类的路径。