spring BeanCreationException关于映射的困惑

Question

试图整合hibernate和spring,我遇到了这个错误

严重:上下文初始化失败 org.springframework.beans.factory.BeanCreationException:创建名为' org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping'的bean时出错:bean的初始化失败; 嵌套异常是java.lang.IllegalStateException:无法将处理程序' org.me.spring.hib.school.web.SchoolController#0' 映射到URL路径[ /allschools]:已经有类型[class org.me.spring.hib.school.web.SchoolController]映射的处理程序.

我的控制器看起来像

package org.me.spring.hib.school.web;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.me.spring.hib.school.dao.SchoolDAO;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class SchoolController {
    private SchoolDAO schoolDao;

    public SchoolDAO getSchoolDao() {
        return schoolDao;
    }

    public void setSchoolDao(SchoolDAO schoolDao) {
        this.schoolDao = schoolDao;
    }
        @RequestMapping("/allschools")
    public ModelAndView showAllSchools(HttpServletRequest request,HttpServletResponse response) throws Exception{
        if(this.schoolDao ==null){
            System.out.println("this.schoolDao is null");
        }
        ModelMap modelMap = new ModelMap();
        modelMap.addAttribute("schoolsList", this.schoolDao.getAllSchools());
        return new ModelAndView("allschools", modelMap);
    }

}

我在应用程序上下文文件中注入了dao实现

    <context:component-scan base-package="org.me.spring.hib.school.web" />

    <bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate"> 
       <property name="sessionFactory" >
           <ref bean="sessionFactory" />
       </property>    
    </bean>

    <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
       <property name="dataSource">
          <ref local="dataSource"/>
       </property>
       <property name="annotatedClasses">
            <list>
                <value>org.me.spring.hib.school.domain.School</value>
                <value>org.me.spring.hib.school.domain.Teacher</value>
                <value>org.me.spring.hib.school.domain.Student</value>
            </list>
       </property>


       <property name="hibernateProperties">
        <props>
                <prop key="hibernate.dialect"> org.hibernate.dialect.HSQLDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">create</prop>
        </props>
       </property>

   </bean>

    <bean id="schoolDao" class="org.me.spring.hib.school.dao.SchoolDAOImpl">
        <property name="hibernateTemplate" ref="hibernateTemplate" />
    </bean>


    <bean  class="org.me.spring.hib.school.web.SchoolController" >
            <property name="schoolDao" ref="schoolDao" />
    </bean>

我无法弄清楚为什么 SchoolController#0要映射到网址.

Answer 1

发生这种情况是因为你有两者

<context:component-scan base-package="org.me.spring.hib.school.web" />

和

<bean  class="org.me.spring.hib.school.web.SchoolController" >

第一行将自动发现并SchoolController为您注册.通过明确声明另一个,您将获得重复,并且url-mapping将发生冲突.

您需要删除<context:component-scan>或删除控制器和DAO的显式bean定义.如果您执行后者,那么您将需要使用自动装配来注入其依赖项.