找不到在xml中定义的bean

Question

我是spring mvc的新手，我有一个问题是如何知道标签是否正在扫描正确的包？ 例如： 我已经定义了一个名为

的标签

<context:component-scan base-package="spring.mvc"/>

此套餐位置如下：

当我在user-beans.xml中定义bean时，例如

    <bean id="userService" class="spring.mvc.service.UserServiceImpl" />

用户-beans.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" 
	   xmlns:context="http://www.springframework.org/schema/context" 
	   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	   xsi:schemaLocation=" http://www.springframework.org/schema/beans  
	   						http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
	   						http://www.springframework.org/schema/context  
	   						http://www.springframework.org/schema/context/spring-context-3.0.xsd">
    
    <context:component-scan base-package="spring.mvc"/>
    <context:annotation-config />
    
    <bean id="userService" class="spring.mvc.service.UserServiceImpl" />
    <bean id="userDao" class="spring.mvc.dao.UserDaoImpl" />
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="datasource" />
    </bean>
    
    <bean id="datasource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/myusers" />
        <property name="username" value="root" />
        <property name="password" value="root" />
    </bean>
</beans>

似乎在我为class =“”

输入的路径中找不到bean

错误如下所示：

19:44:19.399 [localhost-startStop-1] WARN  o.s.w.c.s.XmlWebApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.CannotLoadBeanClassException: Cannot find class [spring.mvc.service.UserServiceImpl] for bean with name 'userService' defined in class path resource [config/user-beans.xml]; nested exception is java.lang.ClassNotFoundException: spring.mvc.service.UserServiceImpl
19:44:19.399 [localhost-startStop-1] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@65f7a781: defining beans [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,org.springframework.context.event.internalEventListenerProcessor,org.springframework.context.event.internalEventListenerFactory,userService,userDao,jdbcTemplate,datasource,org.springframework.web.servlet.view.InternalResourceViewResolver#0]; root of factory hierarchy
19:44:19.433 [localhost-startStop-1] ERROR o.s.web.servlet.DispatcherServlet - Context initialization failed
org.springframework.beans.factory.CannotLoadBeanClassException: Cannot find class [spring.mvc.service.UserServiceImpl] for bean with name 'userService' defined in class path resource [config/user-beans.xml]; nested exception is java.lang.ClassNotFoundException: spring.mvc.service.UserServiceImpl
	at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1385) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.determineTargetType(AbstractAutowireCapableBeanFactory.java:641) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.predictBeanType(AbstractAutowireCapableBeanFactory.java:609) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1484) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.isFactoryBean(AbstractBeanFactory.java:1007) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:741) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:866) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:542) ~[spring-context-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:668) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:634) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:682) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:553) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:494) ~[spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:138) [spring-webmvc-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at javax.servlet.GenericServlet.init(GenericServlet.java:158) [servlet-api.jar:3.1.FR]
	at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1183) [catalina.jar:8.5.15]
	at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1099) [catalina.jar:8.5.15]
	at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:989) [catalina.jar:8.5.15]
	at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4931) [catalina.jar:8.5.15]
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5241) [catalina.jar:8.5.15]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) [catalina.jar:8.5.15]
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1419) [catalina.jar:8.5.15]
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409) [catalina.jar:8.5.15]
	at java.util.concurrent.FutureTask.run(Unknown Source) [na:1.8.0_131]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [na:1.8.0_131]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [na:1.8.0_131]
	at java.lang.Thread.run(Unknown Source) [na:1.8.0_131]
Caused by: java.lang.ClassNotFoundException: spring.mvc.service.UserServiceImpl
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1285) ~[catalina.jar:8.5.15]
	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119) ~[catalina.jar:8.5.15]
	at org.springframework.util.ClassUtils.forName(ClassUtils.java:250) ~[spring-core-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanDefinition.resolveBeanClass(AbstractBeanDefinition.java:401) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doResolveBeanClass(AbstractBeanFactory.java:1432) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.resolveBeanClass(AbstractBeanFactory.java:1377) ~[spring-beans-4.3.7.RELEASE.jar:4.3.7.RELEASE]
	... 26 common frames omitted

有人可以解释组件扫描的工作原理吗？

提前致谢

Answer 1

验证UserServiceImpl级中的以下两点：
1.检查班级中的包裹声明。它应与spring.mvc.service相同 2.检查班级中是否添加了班级注释（@Component/@Service）。