尝试访问dao bean时，注入自动连接的依赖项失败 [英] Injection of autowired dependencies failed while trying to access dao bean

问题描述

访问网页时出错。这是我的代码 -

web.xml文件 -

 < ;欢迎-文件列表> 
< welcome-file> index.jsp< / welcome-file> 
< / welcome-file-list> 
< 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> 
  

带名称的调度程序servlet - dispatcher-servlet.xml

 < context：annotation-config /> 
< context：component-scan base-package =com.webProject.controller>< / context：component-scan> 
<！ - < context：component-scan base-package =com.webProject> 
< context：include-filter type =aspectjexpression =com.webProject。*/> 
< / context：component-scan> 
  - > 
 
< bean id =jspViewResolverclass =org.springframework.web.servlet.view.InternalResourceViewResolver> 
< property name =viewClassvalue =org.springframework.web.servlet.view.JstlView/> 
< property name =prefixvalue =/ WEB-INF / jsp //> 
< property name =suffixvalue =。jsp/> 
< / bean> 
 
< bean id =mysqlDataSourceclass =org.apache.commons.dbcp.BasicDataSource
 destroy-method =close> 
< property name =driverClassNamevalue =com.mysql.jdbc.Driver/> 
< property name =urlvalue =jdbc：mysql：// localhost：3306 / school/> 
< property name =usernamevalue =root/> 
< property name =passwordvalue =test/> 
< / bean> 
< bean id =mySessionFactory
 class =org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean> 
< property name =dataSourceref =mysqlDataSource/> 
< property name =annotatedClasses> 
< list> 
< value> com.webProject.model.Student< / value> 
< / list> 
< / property> 
< property name =hibernateProperties> 
< props> 
< prop key =hibernate.dialect> org.hibernate.dialect.MySQLDialect< /丙> 
< prop key =hibernate.show_sql> true< / prop> 
< prop key =hibernate.hbm2ddl.auto> create< / prop> 
< prop key =javax.persistence.validation.mode> none< / prop> 
< prop key =connection.autocommit> true< / prop> 
< / props> 
< / property> 
< / bean> 
< bean id =hibernateTemplateclass =org.springframework.orm.hibernate3.HibernateTemplate> 
< property name =sessionFactoryref =mySessionFactory/> 
< / bean> 
<！ - < bean id =studentDaoclass =com.webProject.dao.StudentDaoImpl>< / bean>  - > 
 
 
< / beans> 
  

学生控制器课程 -

  package com.webProject.controller; 
 
 @Controller 
 @RequestMapping（/ Student）
 
公共类StudentController {
 @Autowired 
 private IStudentDao studentDao; 
 //列表< Student>学生们; 
 
 / * public StudentController（）{
 students = new ArrayList< Student>（）; 
} * / 
 
 public IStudentDao getStudentDao（）{
 return studentDao; 
} 
 
 public void setStudentDao（IStudentDao studentDao）{
 this.studentDao = studentDao; 
} 
 
 @RequestMapping（value =details / {number}，method = RequestMethod.GET）
 public String studentDetails（@PathVariable（number）int studentNumber，模型模型）{
 //学生= this.students.get（studentNumber）; 
学生=（学生）getStudentDao（）。load（new Long（studentNumber））; 
 model.addAttribute（学生，学生）; 
 model.addAttribute（studentNumber，Integer.toString（studentNumber））; 
返回studentDetails; 
 
} 
 
 @RequestMapping（value =addStudent，method = RequestMethod.POST）
 public String addStudent（@ModelAttribute（student）学生，模型模型）{
 
 if（student！= null）{
 getStudentDao（）。save（student）; 
 //this.students.add(student）; 
 model.addAttribute（学生，学生）; 
 model.addAttribute（studentNumber，Integer.toString（getStudentDao（）。count（）））; 
返回studentAddSuccess; 
} else {
抛出新的NullPointerException（）; 
} 
} 
 
 @RequestMapping（value =studentRegistration）
 public String sendStudentForm（Model model）{
 
 Student student =新生（）; 
 model.addAttribute（学生，学生）; 
 
返回studentForm; 
} 
 
 @RequestMapping（value =delete / {studentNumber}）
 public String deleteStudent（@PathVariable（studentNumber）int studentNumber，Model model）{
 
学生=（学生）getStudentDao（）。load（new Long（studentNumber））; 
 model.addAttribute（std，student）; 
 getStudentDao（）。deleteById（new Long（studentNumber））; 
返回deleteStudent; 
 
} 
 
 
} 
  

studentform.jsp

 < body> 
< form：form method =postmodelAttribute =studentaction =addStudent> 
 
< table> 
 
< tr> 
< td>学生姓名< / td> 
< td>格式：输入路径=studentName< / td> 
< / tr> 
< tr> 
< td>部门< / td> 
< td>格式：输入路径=部门< / td> 
< / tr> 
< tr> 
< td> College< / td> 
< td>格式：输入路径=collegeName< / td> 
< / tr> 
< tr> 
< td colspan =3>< input type =submit/>< / td> 
< / tr> 
 
< / table> 
 
< / form：form> 
 
< / body> 
  

当我提到 -

我得到一个错误，因为资源没有发现。所以我尝试将我的所有包裹包括在内 -

 < context：component-scan base-package =com.webProject.controller >< /上下文：组分扫描> 
< context：component-scan base-package =com.webProject.dao>< / context：component-scan> 
< context：component-scan base-package =com.webProject.model>< / context：component-scan>但后来我也得到相同的资源未找到错误。我尝试了另一种方式中提到的另一种方式 -  http://stackoverflow.com/questions/7914363/injection-of-autowired-dependencies-failed 
< context：component-scan base-package =com.webProject > 
< context：include-filter type =aspectjexpression =com.webProject。*/> 
< / context：component-scan> 
  

但同样的结果 - 资源未找到。

所以只有当我给这个base-package =com.webProject.controller时，我才会收到资源未找到错误，但后来又出现了另一个错误 -

org.springframework.beans.factory.BeanCreationException：创建名为'studentController'的bean时出错：注入自动连接的依赖项失败;

嵌套异常是org.springframework.beans.factory.BeanCreationException：无法自动装配字段：private com.webProject.dao.IStudentDao

com.webProject.controller.StudentController.studentDao;嵌套异常是org.springframework.beans.factory.NoSuchBeanDefinitionException：没有匹配

找到依赖的类型为[com.webProject.dao.IStudentDao]的bean：预期至少为1 bean有资格作为此依赖项的autowire候选者。

依赖注释：{@ org.springframework.beans.factory.annotation.Autowired（required = true）}

<然后我试着注入studentDao，然后我也得到一个错误。

我正在使用Tomcat来部署这个工件。并使用maven来构建这个项目。我不确定spring + hibernate + maven项目是如何在tomcat中运行的？

我最近开始使用spring和hibernate进行编程，这是我使用这些技术的第一个项目。所以请原谅我，如果我犯了一些基本错误。

你可以帮我解决一些问题。

学生Dao -

  package com.webProject.dao; 
 
 import java.util.List; 
 
 import org.hibernate.HibernateException; 
 import org.hibernate.Session; 
 import org.springframework.beans.factory.annotation.Autowired; 
 import org.springframework.orm.hibernate3.HibernateCallback; 
 import org.springframework.orm.hibernate3.HibernateTemplate; 
 
 import com.webProject.model。*; 
 
公共抽象类AbstractHibernateDAOImpl实现AbstractDao {
 
 @Autowired 
 private HibernateTemplate hibernateTemplate; 
 
 public HibernateTemplate getHibernateTemplate（）{
 return hibernateTemplate; 
} 
 
 public void setHibernateTemplate（HibernateTemplate hibernateTemplate）{
 this.hibernateTemplate = hibernateTemplate; 
} 
 
 protected类domainClass = getDomainClass（）; 
 
 / ** 
 *返回域对象类的方法
 * / 
 protected abstract class getDomainClass（）; 
 
 @SuppressWarnings（unchecked）
 public PersistentObject load（Long id）{
 return（PersistentObject）getHibernateTemplate（）。load（domainClass，id）; 
} 
 
 public void update（PersistentObject t）{
 getHibernateTemplate（）。update（t）; 
} 
 
 public void save（PersistentObject t）{
 getHibernateTemplate（）。save（t）; 
} 
 
 public void delete（PersistentObject t）{
 getHibernateTemplate（）。delete（t）; 
} 
 
 @SuppressWarnings（unchecked）
 public List< PersistentObject> getList（）{
 return（getHibernateTemplate（）。find（from+ domainClass.getName（）
 +x））; 
} 
 
 public void deleteById（Long id）{
 Object obj = load（id）; 
 getHibernateTemplate（）。delete（obj）; 
} 
 
 @SuppressWarnings（unchecked）
 public void deleteAll（）{
 getHibernateTemplate（）。execute（new HibernateCallback（）{
 public Object doInHibernate（Session session）
 throws HibernateException {
 String hqlDelete =delete+ domainClass.getName（）; 
 int deletedEntities = session.createQuery（hqlDelete）
 .executeUpdate（ ）; 
返回null; 
} 
 
}）; 
} 
 
 public int count（）{
 List list = getHibernateTemplate（）。find（
select count（*）from+ domainClass.getName（） +x）; 
整数计数=（整数）list.get（0）; 
返回count.intValue（）; 
} 
 
} 
  

student dao interface -

  package com.webProject.dao; 
 
公共接口IStudentDao扩展AbstractDao {
 
} 
  

student dao implementation -

  package com.webProject.dao; 
 
 import org.springframework.stereotype.Repository; 
 
 import com.webProject.model.Student; 
 
 
 @Repository（studentDao）
公共类StudentDaoImpl扩展AbstractHibernateDAOImpl实现IStudentDao {
 
 
 @Override 
 protected getDomainClass（）类$ 
返回Student.class; 
} 
 
} 
  

解决方案

如果您的DAO类放在具有控制器类的不同包中，那么您应该更改组件扫描元素：

 < context：component-scan base-package =com.webProject> 
  

还要检查是否已使用@Repository（或@Component）注释注释了DAO类。

I am getting an error while accessing the web page. here is my code -

web.xml file -

 <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
    <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>

dispatcher servlet with name - "dispatcher-servlet.xml"

    <context:annotation-config />
    <context:component-scan base-package="com.webProject.controller"></context:component-scan>
    <!-- <context:component-scan base-package="com.webProject">
        <context:include-filter type="aspectj" expression="com.webProject.*" />
    </context:component-scan>
    -->

    <bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>

    <bean id="mysqlDataSource" class="org.apache.commons.dbcp.BasicDataSource"
        destroy-method="close">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/school" />
        <property name="username" value="root" />
        <property name="password" value="test" />
    </bean>
    <bean id="mySessionFactory"
        class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
        <property name="dataSource" ref="mysqlDataSource" />
        <property name="annotatedClasses">
            <list>
                <value>com.webProject.model.Student</value>
            </list>
        </property>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect"> org.hibernate.dialect.MySQLDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">create</prop>
                <prop key="javax.persistence.validation.mode">none</prop>
                <prop key="connection.autocommit">true</prop>
            </props>
        </property>
    </bean>
    <bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate">
        <property name="sessionFactory" ref="mySessionFactory" />
    </bean>
    <!-- <bean id="studentDao" class="com.webProject.dao.StudentDaoImpl"></bean>-->


</beans>

Student controller class -

package com.webProject.controller;

@Controller
@RequestMapping("/Student")

public class StudentController {
@Autowired
private IStudentDao studentDao;
//List<Student> students;

/*public StudentController() {
    students = new ArrayList<Student>();
}*/

public IStudentDao getStudentDao() {
    return studentDao;
}

public void setStudentDao(IStudentDao studentDao) {
    this.studentDao = studentDao;
}

@RequestMapping(value="details/{number}",method=RequestMethod.GET)
public String studentDetails(@PathVariable("number") int studentNumber, Model model){
    //Student student = this.students.get(studentNumber);
    Student student = (Student) getStudentDao().load(new Long(studentNumber));
    model.addAttribute("student",student);
    model.addAttribute("studentNumber", Integer.toString(studentNumber));
    return "studentDetails";

}

@RequestMapping(value="addStudent", method=RequestMethod.POST)
public String addStudent(@ModelAttribute("student") Student student, Model model){

    if(student != null){
        getStudentDao().save(student);
        //this.students.add(student);
        model.addAttribute("student", student);
        model.addAttribute("studentNumber", Integer.toString(getStudentDao().count()));
        return "studentAddSuccess";
    }else{
        throw new NullPointerException();
    }   
}

@RequestMapping(value="studentRegistration")
public String sendStudentForm(Model model){

    Student student = new Student();
    model.addAttribute("student", student);

    return "studentForm";
}

@RequestMapping(value="delete/{studentNumber}")
public String deleteStudent(@PathVariable("studentNumber") int studentNumber, Model model){

    Student student = (Student) getStudentDao().load(new Long(studentNumber));
    model.addAttribute("std", student);
    getStudentDao().deleteById(new Long(studentNumber));
    return "deleteStudent";

}


}

studentform.jsp

  <body>
    <form:form method="post" modelAttribute="student" action="addStudent">

<table>

    <tr>
        <td>Student Name</td>
        <td>form:input path="studentName"</td>          
    </tr>
    <tr>
        <td>Department</td>
        <td>form:input path="department"</td>
    </tr>
    <tr>
        <td>College</td>
        <td>form:input path="collegeName"</td>
    </tr>
    <tr>
        <td colspan="3"><input type="submit" /></td>
    </tr>

</table>

   </form:form>

</body>

when i mention - this i get an error as "Resource not found". so i tried including all my packages as-

 <context:component-scan base-package="com.webProject.controller"></context:component-scan>
<context:component-scan base-package="com.webProject.dao"></context:component-scan>
<context:component-scan base-package="com.webProject.model"></context:component-scan> but then also i get same "resource not found" error. i tried another way as mentioned in another thread - http://stackoverflow.com/questions/7914363/injection-of-autowired-dependencies-failed
<context:component-scan base-package="com.webProject">
     <context:include-filter type="aspectj" expression="com.webProject.*" />
</context:component-scan>

but then also same result - "Resource not found".

so only when i give this base-package="com.webProject.controller", then i dont get "Resource not found error", but then it get another error -

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'studentController': Injection of autowired dependencies failed;

nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.webProject.dao.IStudentDao

com.webProject.controller.StudentController.studentDao; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching

bean of type [com.webProject.dao.IStudentDao] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency.

Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

then i tried to inject the studentDao as , then i also i get an error.

I am using Tomcat to deploy this artifact. and using maven to build this project. i am not sure how it spring+ hibernate+ maven project works in tomcat?

I have recently started programming using spring and hibernate and this is my first project using these technologies. so please pardon me if i am making some basic mistake.

can you please help me with some solution.

student Dao -

package com.webProject.dao;

import java.util.List;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.HibernateTemplate;

import com.webProject.model.*;

public abstract class AbstractHibernateDAOImpl implements AbstractDao {

    @Autowired
    private HibernateTemplate hibernateTemplate;

    public HibernateTemplate getHibernateTemplate() {
        return hibernateTemplate;
    }

    public void setHibernateTemplate(HibernateTemplate hibernateTemplate) {
        this.hibernateTemplate = hibernateTemplate;
    }

    protected Class domainClass = getDomainClass();

    /**
     * Method to return the class of the domain object
     */
    protected abstract Class getDomainClass();

    @SuppressWarnings("unchecked")
    public PersistentObject load(Long id) {
        return (PersistentObject) getHibernateTemplate().load(domainClass, id);
    }

    public void update(PersistentObject t) {
        getHibernateTemplate().update(t);
    }

    public void save(PersistentObject t) {
        getHibernateTemplate().save(t);
    }

    public void delete(PersistentObject t) {
        getHibernateTemplate().delete(t);
    }

    @SuppressWarnings("unchecked")
    public List<PersistentObject> getList() {
        return (getHibernateTemplate().find("from " + domainClass.getName()
                + " x"));
    }

    public void deleteById(Long id) {
        Object obj = load(id);
        getHibernateTemplate().delete(obj);
    }

    @SuppressWarnings("unchecked")
    public void deleteAll() {
        getHibernateTemplate().execute(new HibernateCallback() {
            public Object doInHibernate(Session session)
                    throws HibernateException {
                String hqlDelete = "delete " + domainClass.getName();
                int deletedEntities = session.createQuery(hqlDelete)
                        .executeUpdate();
                return null;
            }

        });
    }

    public int count() {
        List list = getHibernateTemplate().find(
                "select count(*) from " + domainClass.getName() + " x");
        Integer count = (Integer) list.get(0);
        return count.intValue();
    }

}

student dao interface -

package com.webProject.dao;

public interface IStudentDao extends AbstractDao{

}

student dao implementation -

package com.webProject.dao;

import org.springframework.stereotype.Repository;

import com.webProject.model.Student;


@Repository ("studentDao")
public class StudentDaoImpl extends AbstractHibernateDAOImpl implements IStudentDao{


    @Override
    protected Class getDomainClass() {
        return Student.class;
    }

}

解决方案

If your DAO classes is placed in different packages with controller classes then you should change your component scan element:

<context:component-scan base-package="com.webProject">

Also check that you have annotated your DAO classes with @Repository (or @Component) annotation.

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