[英]Injection of autowired dependencies failed while trying to access dao bean
訪問網頁時出現錯誤。 這是我的代碼-
web.xml文件-
<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>
名稱的調度程序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="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>
學生控制班-
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>
當我提到-這時,我收到一條錯誤消息“找不到資源”。 所以我嘗試將我所有的包裹都包括在內
<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>
但結果也一樣-“找不到資源”。
因此,僅當我給此base-package =“ com.webProject.controller”時,我才不會收到“找不到資源錯誤”,但隨后又出現另一個錯誤-
org.springframework.beans.factory.BeanCreationException:創建名稱為'studentController'的bean時出錯:自動連接依賴項的注入失敗;
嵌套的異常是org.springframework.beans.factory.BeanCreationException:無法自動連線字段:私有com.webProject.dao.IStudentDao
com.webProject.controller.StudentController.studentDao; 嵌套的異常是org.springframework.beans.factory.NoSuchBeanDefinitionException:沒有匹配項
找到類型為[com.webProject.dao.IStudentDao]的Bean以獲得依賴關系:期望至少有1個符合此依賴關系自動候選條件的bean。
依賴項注釋:{@ org.springframework.beans.factory.annotation.Autowired(required = true)}
然后我嘗試將StudentDao注入,然后我也遇到錯誤。
我正在使用Tomcat部署此工件。 並使用Maven構建該項目。 我不確定spring + hibernate + maven項目在tomcat中如何工作?
我最近開始使用spring和hibernate進行編程,這是我使用這些技術的第一個項目。 因此,如果我犯了一些基本錯誤,請原諒我。
你能幫我一些解決方案嗎?
學生道-
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();
}
}
學生dao界面-
package com.webProject.dao;
public interface IStudentDao extends AbstractDao{
}
學生道實施-
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;
}
}
如果將DAO類與控制器類放在不同的包中,則應更改組件掃描元素:
<context:component-scan base-package="com.webProject">
還要檢查是否已使用@Repository(或@Component)注釋對DAO類進行注釋。
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