我在使用 hibernate 将数据保存到 mysql 时遇到问题。我正在使用 spring mvc 并学习企业应用程序，但在持久保存到数据库中时遇到了一些麻烦。我正在创建两个名为 Persons 的实体，并将其组织到 mysql 数据库中。用于练习的模式称为 Lab2。还使用 Maven 来构建我的项目。我在 myProject/src/main/webapp/WEB-INF 下创建了 webapp 文件夹。我想知道我是否正确配置了 hibernate.cfg.xml。我还在 WEB-INF 文件夹下创建了 hibernate.cfg.xml ，下面是我的代码:
hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="connection.url">jdbc:mysql://localhost:3306/Lab2</property>
<property name="connection.driver_class">org.gjt.mm.mysql.Driver</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>
<!-- DB schema will be updated if needed -->
<property name="hbm2ddl.auto">create</property>
<!--dialect-->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!--will print out sql queries to our console-->
<property name="show_sql">true</property>
<!--names annotated entity class-->
<mapping class="edu.sjsu.cmpe275.lab2.models.Person"></mapping>
<mapping class="edu.sjsu.cmpe275.lab2.models.Organization"></mapping>
</session-factory>
</hibernate-configuration>
通过研究和在线查看什么是 WEB-INF 我必须创建该文件夹，因为它存储 web.xml 并在该文件夹中加载所有已编译的类和可执行文件。
WEB-INF 中还包含我的 web.xml。 web.xml 加载所有配置。我将 hibernate.cfg.xml 文件传递到 web.xml 以及 services.xml(业务逻辑文件)以及目前不执行任何操作的 applicationContext.xml 中。
下面是我的 web.xml 代码:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
version="3.1">
<display-name>Lab 2</display-name>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/applicationContext.xml, /WEB-INF/services.xml, /WEB-INF/hibernate.cfg.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
下面是dispatcher-servlet.xml 文件。该文件监听传入请求并发送响应。它将请求发送到 Controller 。 :
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan base-package="edu.sjsu.cmpe275.lab2.controller" />
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping" />
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter" />
</beans>
我的 service.xml 文件加载 PesronDao 和 OrganizationDao 的服务实现。另外，我决定在这里添加我的数据库配置，因为我将使用 SessionFactory 接口(interface)。我觉得我的错误发生的地方是这样的，因为我无法持久保存到 mysql 中。另外，当我在 Person.java 中定义 @Table 时，我收到一条错误，指出它无法解析表 person。
以下是service.xml:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<bean name="personService" class="edu.sjsu.cmpe275.lab2.service.PersonImpl" autowire="byName"/>
<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/Lab2" />
<property name="username" value="root" />
<property name="password" value="root" />
</bean>
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="annotatedClasses">
<list>
<value>edu.sjsu.cmpe275.lab2.models.Person</value>
<value>edu.sjsu.cmpe275.lab2.models.Organization</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
<prop key="hibernate.show_sql">true</prop>
</props>
</property>
</bean> -->
<context:component-scan base-package="edu.sjsu.cmpe275.lab2.service" />
</beans>
下面是 applicationContext.xml 文件:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">
</beans>
以下是我的错误:
Hibernate: select next_val as id_val from hibernate_sequence for update
03-Nov-2015 18:30:25.837 ERROR [http-nio-8080-exec-5] org.hibernate.id.enhanced.TableStructure$1$1.execute could not read a hi value
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'lab2.hibernate_sequence' doesn't exist
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
at com.mysql.jdbc.Util.getInstance(Util.java:360)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:978)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3887)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3823)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2435)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2582)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2530)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1907)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2030)
at org.hibernate.id.enhanced.TableStructure.executeQuery(TableStructure.java:224)
at org.hibernate.id.enhanced.TableStructure.access$300(TableStructure.java:46)
at org.hibernate.id.enhanced.TableStructure$1$1.execute(TableStructure.java:139)
at org.hibernate.id.enhanced.TableStructure$1$1.execute(TableStructure.java:126)
at org.hibernate.jdbc.WorkExecutor.executeReturningWork(WorkExecutor.java:55)
at org.hibernate.jdbc.AbstractReturningWork.accept(AbstractReturningWork.java:34)
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcIsolationDelegate.delegateWork(JdbcIsolationDelegate.java:56)
at org.hibernate.id.enhanced.TableStructure$1.getNextValue(TableStructure.java:125)
at org.hibernate.id.enhanced.NoopOptimizer.generate(NoopOptimizer.java:42)
at org.hibernate.id.enhanced.SequenceStyleGenerator.generate(SequenceStyleGenerator.java:417)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:101)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:192)
at org.hibernate.event.internal.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:38)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:177)
at org.hibernate.event.internal.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:32)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:73)
at org.hibernate.internal.SessionImpl.fireSave(SessionImpl.java:678)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:670)
at org.hibernate.internal.SessionImpl.save(SessionImpl.java:665)
at edu.sjsu.cmpe275.lab2.service.PersonImpl.createPerson(PersonImpl.java:48)
at edu.sjsu.cmpe275.lab2.controller.Controllers.home(Controllers.java:37)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:806)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:729)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
请有人帮助我，我认为错误来 self 配置 hibernate.cfg.xml 文件以及 services.xml 文件的方式，因为我觉得错误发生的地方。请帮助我发现错误或纠正我做错的事情。
最佳答案
问题是表lab2.hibernate_sequence不存在。 Hibernate 使用该表来保存 pid 序列。当您在配置中执行类似操作时，Hibernate 将创建此表
<property name="hbm2ddl.auto">create</property>
你的配置看起来很奇怪。您在 hibernate.cfg.xml 和 service.xml 中拥有数据库连接属性。这些属性彼此不同。所以我认为 Hibernate 在启动时不会在数据库中创建任何表。
关于java - 使用 hibernate 持久化到 mysql 时出错，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33513299/