Java Spring MVC + Hibernate - sessionFactory "unsatisfied dependency"错误

Question

我正在创建我的第一个 Spring + Hibernate Web 应用程序，这就是我在控制台中的内容:

Root Cause
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'quizDAOImpl': Unsatisfied dependency expressed through field 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in ServletContext resource [/WEB-INF/dispatcher-servlet.xml]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: No identifier specified for entity: com.kubacki.entity.Quiz

我试图找到现有的解决方案，但似乎没有任何效果，您能帮助我吗？

我不确定问题是否可能是由错误的 XML 配置或编码本身的错误引起的，从我的角度来看，“sessionFactory”bean 在 XML 中配置正确，注入(inject)它应该没有问题。

此外，我在这个项目中使用 Maven，但我已经在 pom.xml 中列出了所有 spring + hibernate 内容

这是我的源代码:

QuizDAO:

package com.kubacki.dao;

import java.util.List;

import com.kubacki.entity.Quiz;

public interface QuizDAO {

    public Quiz getQuiz(int id);

    public List<Quiz> getQuizzes();

}

QuizDAOImpl:

package com.kubacki.dao;

import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.query.Query;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import com.kubacki.entity.Quiz;

@Repository
public class QuizDAOImpl implements QuizDAO {

    @Autowired
    private SessionFactory sessionFactory;

    @Override
    public Quiz getQuiz(int id) {

        Session tempSession = sessionFactory.getCurrentSession();

        Quiz tempQuiz = tempSession.get(Quiz.class, id);

        return tempQuiz;
    }

    @Override
    public List<Quiz> getQuizzes() {

        Session tempSession = sessionFactory.getCurrentSession();

        Query<Quiz> theQuery = tempSession.createQuery("from quiz", Quiz.class);

        List<Quiz> tempQuizzes = theQuery.getResultList();

        return tempQuizzes;
    }

}

Web.xml:

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>

  <display-name>WebApp</display-name>

    <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>

调度程序-servlet.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"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    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
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/tx 
        http://www.springframework.org/schema/tx/spring-tx.xsd">

    <!-- Add support for component scanning -->
    <context:component-scan base-package="com.kubacki" />

    <!-- Add support for conversion, formatting and validation support -->
    <mvc:annotation-driven/>

    <!-- Define Spring MVC view resolver -->
    <bean
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/view/" />
        <property name="suffix" value=".jsp" />
    </bean>

    <!-- Step 1: Define Database DataSource / connection pool -->
    <bean id="myDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
          destroy-method="close">
        <property name="driverClass" value="com.mysql.jdbc.Driver" />
        <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/quizdb?useSSL=false" />
        <property name="user" value="root" />
        <property name="password" value="admin" /> 

        <!-- these are connection pool properties for C3P0 -->
        <property name="minPoolSize" value="5" />
        <property name="maxPoolSize" value="20" />
        <property name="maxIdleTime" value="30000" />
    </bean>  

    <!-- Step 2: Setup Hibernate session factory -->
    <bean id="sessionFactory"
        class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
        <property name="dataSource" ref="myDataSource" />
        <property name="packagesToScan" value="com.kubacki.entity" />
        <property name="hibernateProperties">
           <props>
              <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
              <prop key="hibernate.show_sql">true</prop>
           </props>
        </property>
   </bean>    

    <!-- Step 3: Setup Hibernate transaction manager -->
    <bean id="myTransactionManager"
            class="org.springframework.orm.hibernate5.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean>

    <!-- Step 4: Enable configuration of transactional behavior based on annotations -->
    <tx:annotation-driven transaction-manager="myTransactionManager" />


</beans>

Answer 1

根据错误

No identifier specified for entity: com.kubacki.entity.Quiz

我认为，您缺少 Quiz 类中用 @Id 注释的字段。每个@Entity 必须有一个@Id - 这将是数据库中的主键。