spring @Autowired - 没有找到至少 1 个依赖项的符合条件的 bean
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@Autowired - No qualifying bean of type found for dependency at least 1 bean
提问by Arun
Currently I'm facing an issue in Autowire configuration between controller and the service layer.
目前，我在控制器和服务层之间的 Autowire 配置中遇到了问题。
I'm unable to trace my mistakes.
我无法追踪我的错误。
Simple Log Info
简单日志信息
SEVERE: Exception while loading the app
SEVERE: Undeployment failed for context /OTT
SEVERE: Exception while loading the app : java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: org.apache.catalina.LifecycleException: org.springframework.beans.factory.NoSuchBeanDefinitionException:
No qualifying bean of type [com.ott.service.EmployeeService] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}
Below I have also given the Controller and Service Layer code and also the dispatcher-servlet.xml
下面我还给出了控制器和服务层代码以及 dispatcher-servlet.xml
Controller
控制器
package com.ott.controller;
import com.ott.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
/**
*
* @author SPAR
*/
@Controller
public class AdminController {
private EmployeeService employeeService;
@RequestMapping("/employee")
public String employee(){
this.employeeService.fetchAll();
return "employee";
}
@Autowired(required = true)
@Qualifier(value="employeeService")
public void setEmployeeService(EmployeeService empService) {
this.employeeService = empService;
}
}
Service Interface
服务接口
package com.ott.service;
import com.ott.hibernate.Employee;
import java.util.List;
/**
*
* @author SPAR
*/
public interface EmployeeService {
List<Employee> fetchAll();
}
Service Interface Impl
服务接口实现
package com.ott.service;
import com.ott.dao.EmployeeDAO;
import com.ott.hibernate.Employee;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
/**
*
* @author SPAR
*/
@Service
public class EmployeeServiceImpl implements EmployeeService{
private EmployeeDAO employeeDAO;
@Override
@Transactional(readOnly = true)
public List<Employee> fetchAll() {
List<Employee> employees = employeeDAO.fetchAll();
for (Employee employee : employees) {
System.out.println("Name : "+employee.getFirst_Name() +" "+ employee.getLast_Name());
System.out.println("Email Id : "+employee.getEmail_Id());
}
return employees;
}
@Autowired(required = true)
@Qualifier(value="employeeDAO")
public void setEmployeeDAO(EmployeeDAO empDAO) {
this.employeeDAO = empDAO;
}
}
Dispatcher-servlet.xml
Dispatcher-servlet.xml
<?xml version='1.0' encoding='UTF-8' ?>
<!-- was: <?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:p="http://www.springframework.org/schema/p"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">
<context:component-scan base-package="com.ott.controller"/>
<context:component-scan base-package="com.ott.hibernate"/>
<context:component-scan base-package="com.ott.service"/>
<context:component-scan base-package="com.ott.dao"/>
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"/>
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"/>
<mvc:resources mapping="/resources/**" location="/resources/" />
<bean id="tilesConfigurer" class="org.springframework.web.servlet.view.tiles3.TilesConfigurer">
<property name="definitions">
<list>
<value>/WEB-INF/tiles-def/general-layout.xml</value>
</list>
</property>
</bean>
<bean id="viewResolverTiles" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.tiles3.TilesView"/>
</bean>
<mvc:annotation-driven />
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix">
<value>/WEB-INF/pages/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
</beans>
采纳答案by minion
You don't have to necessarily provide name and Qualifier. If you set a name, that's the name with which the bean is registered in the context. If you don't provide a name for your service it will be registered as uncapitalized non-qualified class name based on BeanNameGenerator. So in your case the Implementation will be registered as employeeServiceImpl. So if you try to autowire with that name, it should resolve directly.
您不必一定提供名称和限定符。如果您设置了一个名称，它就是在上下文中注册 bean 的名称。如果您没有为您的服务提供名称，它将被注册为基于BeanNameGenerator. 因此，在您的情况下，实施将注册为employeeServiceImpl. 因此，如果您尝试使用该名称自动装配，它应该直接解析。
private EmployeeService employeeServiceImpl;
@RequestMapping("/employee")
public String employee() {
this.employeeService.fetchAll();
return "employee";
}
@Autowired(required = true)
public void setEmployeeService(EmployeeService employeeServiceImpl) {
this.employeeServiceImpl = employeeServiceImpl;
}
@Qualifieris used in case if there are more than one bean exists of same type and you want to autowire different implementation beans for various purposes.
@Qualifier如果存在多个相同类型的 bean 并且您想为各种目的自动装配不同的实现 bean，则使用。
回答by Arun
Guys I found the issue
伙计们，我发现了这个问题
I just tried by adding the qualifier name in employee service finally it solved my issue.
我只是尝试通过在员工服务中添加限定符名称终于解决了我的问题。
@Service("employeeService")
public class EmployeeServiceImpl implements EmployeeService{
}
回答by Ramesh Kotha
I believe for @Serviceyou have to add qualifier name like below :
我相信@Service您必须添加如下限定符名称：
@Service("employeeService")should solve your issue
@Service("employeeService")应该能解决你的问题
or after @Serviceyou should add @Qualifierannontion like below :
或者在@Service你应该添加@Qualifier如下 annontion之后：
@Service
@Qualifier("employeeService")
回答by kaustubh kamat
In your controller class, just add @ComponentScan("package") annotation. In my case the package name is com.shoppingcart.So i wrote the code as @ComponentScan("com.shoppingcart") and it worked for me.
在您的控制器类中，只需添加 @ComponentScan("package") 注释。在我的情况下，包名称是 com.shoppingcart。所以我将代码编写为 @ComponentScan("com.shoppingcart") 并且它对我有用。
回答by Resul Rzaeeff
You forgot @Service annotation in your service class.
您忘记了服务类中的 @Service 注释。
回答by Narayan Yerrabachu
@Service: It tells that particular class is a Service to the client. Service class contains mainly business Logic. If you have more Service classes in a package than provide @Qualifier otherwise it should not require @Qualifier.
@Service：它告诉特定的类是客户端的服务。服务类主要包含业务逻辑。如果包中的服务类多于提供@Qualifier，否则它不应该需要@Qualifier。
Case 1:
情况1：
@Service("employeeService")
public class EmployeeServiceImpl implements EmployeeService{
}
Case2:
案例2：
@Service
public class EmployeeServiceImpl implements EmployeeService{
}
both cases are working...
两种情况都在工作......
回答by user7839057
Just add below annotation with qualifier name of service in service Implementation class:
只需在服务实现类中添加以下带有服务限定符名称的注释：
@Service("employeeService")
@Transactional
public class EmployeeServiceImpl implements EmployeeService{
}
回答by Mariuszy
If you only have one bean of type EmployeeService, and the interface EmployeeService does not have other implementations, you can simply put "@Service" before the EmployeeServiceImpl and "@Autowire" before the setter method. Otherwise, you should name the special bean like @Service("myspecial") and put "@autowire @Qualifier("myspecial") before the setter method.
如果您只有一个 EmployeeService 类型的 bean，并且接口 EmployeeService 没有其他实现，则可以简单地将“@Service”放在 EmployeeServiceImpl 之前，将“@Autowire”放在 setter 方法之前。否则，您应该将特殊 bean 命名为 @Service("myspecial") 并将 "@autowire @Qualifier("myspecial") 放在 setter 方法之前。
回答by Laxman Jaygonde
Missing the 'implements' keyword in the impl classes might also be the issue
在 impl 类中缺少“implements”关键字也可能是问题所在
