Question

当我尝试使用@Autowired时，它给了我例外

我使用@Autowired annotation

添加的内容

context：annotation-config /
bean id =“GoAnalyserService”class =“com.dataanalyser.serviceimpl.GoAnalyserServiceImpl”/
context：component-scan base-package =“com.dataanalyser.service”/

我的spring-dispatcher-servlet

<?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:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-3.1.xsd
    http://www.springframework.org/schema/mvc
    http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
    http://www.springframework.org/schema/util
    http://www.springframework.org/schema/util/spring-util-3.1.xsd">

    <context:component-scan base-package="com.dataanalyser.controller"/>
    <!-- <context:component-scan base-package="com.dataanalyser"/> -->
    <context:component-scan base-package="com.dataanalyser.dao"/>
    <context:component-scan base-package="com.dataanalyser.service"/> 
    <mvc:annotation-driven/>

    <mvc:default-servlet-handler/>
    <context:annotation-config />

    <bean id="viewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name = "prefix" value="/WEB-INF/" />            
        <property name = "suffix" value = ".html" />
    </bean>    

    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="org.postgresql.Driver" />
        <property name="url" value="jdbc:postgresql://localhost:5432/GoAnalyserDB" />
        <property name="username" value="postgres" />
        <property name="password" value="toor" />
    </bean>

    <bean id = "goAnalyserService" class = "com.dataanalyser.serviceimpl.GoAnalyserServiceImpl"/>
    <bean id = "userDao" class = "com.dataanalyser.daoimpl.UserDaoImpl"/>
</beans>

我的控制器类

@Controller
public class GoAnalyserControl {

    public GoAnalyserControl()
    {
        System.out.println("------- Inside the controller -------");
    }

    @Autowired
    GoAnalyserService goAnalyserService;

    @RequestMapping(value = "/logInChecker", method = RequestMethod.POST, consumes = {"application/json"})
    public @ResponseBody String logInCheckerFn(@RequestBody UserLogData userLogData){
        System.out.println("inside loginChecker()");
        //GoAnalyserService goAnalyserService = new GoAnalyserServiceImpl(); 
        Integer userAuthFlag = goAnalyserService.checkUserAuth(userLogData);
        System.out.println(userAuthFlag.toString());
        return userAuthFlag.toString();
    }
}

我的服务类

public interface GoAnalyserService {

    public Integer checkUserAuth(UserLogData userLogData);

}

我的服务实施类

public class GoAnalyserServiceImpl implements GoAnalyserService {

    @Autowired
    UserDao userDao;

    @Override 
    public Integer checkUserAuth(UserLogData userLogData){
        //UserDao userDao = new UserDaoImpl(); 
        if((userDao.getUserCount(userLogData.getUserName())) == 1){
            String dbPass = userDao.getUserPass(userLogData.getUserName());
            if( dbPass.equals(userLogData.getPassword()))
                return 1;
            else
                return 2;
        }else
            return 0;
    }

}

当我在没有@Autowired注释的情况下试用它时，这段代码很好用，但是当我添加@Autowired它给了我

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'goAnalyserControl': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.dataanalyser.service.GoAnalyserService com.dataanalyser.controller.GoAnalyserControl.goAnalyserService; nested exception is org.springframework.beans.factory.CannotLoadBeanClassException: Cannot find class [com.dataanalyser.serviceimpl.GoAnalyserService] for bean with name 'GoAnalyserService' defined in ServletContext resource [/WEB-INF/spring-dispatcher-servlet.xml]; nested exception is java.lang.ClassNotFoundException: com.dataanalyser.serviceimpl.GoAnalyserService
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.dataanalyser.service.GoAnalyserService com.dataanalyser.controller.GoAnalyserControl.goAnalyserService; nested exception is org.springframework.beans.factory.CannotLoadBeanClassException: Cannot find class [com.dataanalyser.serviceimpl.GoAnalyserService] for bean with name 'GoAnalyserService' defined in ServletContext resource [/WEB-INF/spring-dispatcher-servlet.xml]; nested exception is java.lang.ClassNotFoundException: com.dataanalyser.serviceimpl.GoAnalyserService
Caused by: org.springframework.beans.factory.CannotLoadBeanClassException: Cannot find class [com.dataanalyser.serviceimpl.GoAnalyserService] for bean with name 'GoAnalyserService' defined in ServletContext resource [/WEB-INF/spring-dispatcher-servlet.xml]; nested exception is java.lang.ClassNotFoundException: com.dataanalyser.serviceimpl.GoAnalyserService

还有更多这样的，我认为spring-dispatcher-servlet.xml中出现了问题，我搜索了很多，仍然无法找到错误的东西。我有任何需要添加到项目中的jar文件.... ??

Answer 1

将@Repo放在GoAnalyserServiceImpl类
上

当您使用@Autowired时，您可能无法解决创建对象的问题。并且使用@Autowired必须位于类@Controller or @Repo or @Service / only @Component.之上注释用于将类标记为Spring 3中的控制器。

Answer 2

尝试删除

    <bean id = "goAnalyserService" class = "com.dataanalyser.serviceimpl.GoAnalyserServiceImpl"/>

来自xml配置。

并将GoAnalyserServiceImpl注释为@Component。

Answer 3

首先，确保您在XML中声明的类存在于包中。然后，使用@Component注释注释您的类。 Spring使用这些注释来查找在使用@Autowired时应该实例化的类。

Answer 4

您的组件扫描声明是：

<context:component-scan base-package="com.dataanalyser.service"/>

，而您的异常消息指出：

Cannot find class com.dataanalyser.serviceimpl.GoAnalyserService

因此，组件扫描中的包声明错误。成功：

<context:component-scan base-package="com.dataanalyser.serviceimpl"/>

或将课程的包更改为com.dataanalyser.service

当然假设您的服务类已正确注释

@Autowired字段导致org.springframework.beans.factory.BeanCreationException

4 个答案: