为什么从hibernate.cfg.xml切换到Autowired时，sessionFactory显示空异常？

如何解决为什么从hibernate.cfg.xml切换到Autowired时，sessionFactory显示空异常？

我已经分别使用hibernate配置文件尝试了此代码，并且运行良好。但是，我没有所有2个xml文件，而是将所有hibernate.cfg.xml数据放入spring-servlet.xml中，并尝试使用自动装配注释。但这给了我们空指针异常。

我的代码结构是

我的代码是

Student.java

package com.wipro.bean;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="Student")
public class Student  {
    @Id
    private String studentId;
    @Column
    private String studentName;
    private String studentSubject;
    public String getStudentId() {
        return studentId;
    }
    public void setStudentId(String studentId) {
        this.studentId = studentId;
    }
    public String getStudentName() {
        return studentName;
    }
    public void setStudentName(String studentName) {
        this.studentName = studentName;
    }
    public String getStudentSubject() {
        return studentSubject;
    }
    public void setStudentSubject(String studentSubject) {
        this.studentSubject = studentSubject;
    }
    @Override
    public String toString() {
        return "Student [studentId=" + studentId + ",studentName=" + studentName + ",studentSubject=" + studentSubject
                + "]";
    }
    
    
}

ControllerStudent.java

package com.wipro.controller;

import java.util.List;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import com.wipro.dao.StudentDao;

@Controller
public class ControllerStudent {
    
    private ApplicationContext conn;
    
    
    @RequestMapping("/show")
    public String view3(Model m) {
        conn=new ClassPathXmlApplicationContext("ApplicationContext.xml");
        StudentDao obj=conn.getBean("dao",StudentDao.class);
        List l=obj.showData();
        m.addAttribute("msg",l);
        return "show";
    }
    
}

StudentDao.java

package com.wipro.dao;

import java.util.List;

import javax.transaction.Transactional;

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

public class StudentDao {

    @Autowired
    private SessionFactory sessionFactory;
    
    private Session session;
    
public List showData() {
        
        //factory =new Configuration().configure(new File("F:/Wipro teachings/springg/crudStudent/src/main/java/com/wipro/bean/hibernate.cfg.xml")).buildSessionFactory();
            session=sessionFactory.openSession();
            Query q=session.createQuery("from Student");
            List list=q.list();
            return list;
        
    }
}

ApplicationContext.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:p="http://www.springframework.org/schema/p"  
    xsi:schemaLocation="http://www.springframework.org/schema/beans  
               http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
         
 <bean id="dao" class="com.wipro.dao.StudentDao"></bean>              
</beans>

spring-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"  
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:jee="http://www.springframework.org/schema/jee"
xmlns:lang="http://www.springframework.org/schema/lang"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:util="http://www.springframework.org/schema/util"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   
    xmlns:context="http://www.springframework.org/schema/context"  
    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/aop
http://www.springframework.org/schema/aop/spring-aop.xsd  
http://www.springframework.org/schema/jee
http://www.springframework.org/schema/jee/spring-jee.xsd
http://www.springframework.org/schema/lang
http://www.springframework.org/schema/lang/spring-lang.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util.xsd"> 
        

        
        <context:component-scan base-package="com.wipro"></context:component-scan>
        
        <mvc:annotation-driven></mvc:annotation-driven>
        
        
        
        <bean id="vr" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name="prefix" value="/WEB-INF/views/"></property>
            <property name="suffix" value=".jsp"></property>
        </bean>
        
         <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver" />
        <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl" />
        <property name="username" value="sys as sysdba" />
        <property name="password" value="Muskan123" />
    </bean>
    
    <bean id="sessionFactory" class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.Oracle8iDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>
        <property name="packagesToScan" value="com.wipro.bean" />
    </bean>
    
    <bean id="hibernateTemplate" class="org.springframework.orm.hibernate5.HibernateTemplate">
        <property name="sessionFactory" ref="sessionFactory"></property>
    </bean>
    
    <tx:annotation-driven />
    
    <bean id="transactionManager" class="org.springframework.orm.hibernate5.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory" />
    </bean> 
        
        <context:annotation-config />
        </beans>

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>Archetype Created Web Application</display-name>
    
    <servlet>
    <servlet-name>spring</servlet-name>
    <servlet-class> org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet>
    
    <servlet-mapping>
        <servlet-name>spring</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>


</web-app>

pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.wipro</groupId>
  <artifactId>crudStudent</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>crudStudent Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    
      
        <dependency>  
        <groupId>org.springframework</groupId>  
        <artifactId>spring-core</artifactId>  
        <version>5.2.1.RELEASE</version>  
    </dependency> 
     
    <dependency>  
        <groupId>org.springframework</groupId>  
        <artifactId>spring-web</artifactId>  
        <version>5.2.1.RELEASE</version>  
    </dependency>  
    
    <dependency>  
        <groupId>org.springframework</groupId>  
        <artifactId>spring-webmvc</artifactId>  
        <version>5.1.1.RELEASE</version>  
    </dependency>  
  
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-core</artifactId>
      <version>5.4.9.Final</version>
    </dependency>
    
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-orm</artifactId>
      <version>5.2.1.RELEASE</version>
    </dependency>
    
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>5.2.6.RELEASE</version>
    </dependency>
    
    <dependency>
      <groupId>commons-dbcp</groupId>
      <artifactId>commons-dbcp</artifactId>
      <version>1.2.2</version>
    </dependency>
    
    <dependency>
      <groupId>com.oracle.database.jdbc</groupId>
      <artifactId>ojdbc6</artifactId>
      <version>11.2.0.4</version>
    </dependency> 
    
    
  </dependencies>

  <build>
    <finalName>crudStudent</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

show.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
    <%@page isELIgnored="false" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<h2>${msg}</h2>
</body>
</html>

index.jsp

<html>
<body>
<h2>Hello World!</h2>

<a href="show">Show Students</a>

</body>
</html>

我不知道错误在哪里。我仅在stackoverflow上看到过类似的其他问题，但是那里的答案都没有帮助我。请帮我提供此代码。

为什么从hibernate.cfg.xml切换到Autowired时，sessionFactory显示空异常？

如何解决为什么从hibernate.cfg.xml切换到Autowired时，sessionFactory显示空异常？

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