java - 创建名称为 'employeeController' : Injection of autowired dependencies failed 的 bean 时出错

Question

我尝试使用 MvcConfiguration.java 作为 Dispatcher 文件进行配置。但是在为 Controller 和 DAO 文件创建 bean 时它会抛出错误。

我知道 stackoverflow 上有很多关于此错误的问题。但我无法解决并陷入困境。

以下是我发现以下错误的文件。

EmployeeController.java

package com.jwt.controller;
import java.io.IOException;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import org.jboss.logging.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
import com.jwt.model.Employee;
import com.jwt.service.EmployeeService;

@Controller
public class EmployeeController {

    private static final Logger logger = Logger
            .getLogger(EmployeeController.class);

    public EmployeeController() {
        System.out.println("EmployeeController()");
    }

    @Autowired
    private EmployeeService employeeService;

    @RequestMapping(value = "/")
    public ModelAndView listEmployee(ModelAndView model) throws IOException {
        List<Employee> listEmployee = employeeService.getAllEmployees();
        model.addObject("listEmployee", listEmployee);
        model.setViewName("home");
        return model;
    }

    @RequestMapping(value = "/newEmployee", method = RequestMethod.GET)
    public ModelAndView newContact(ModelAndView model) {
        Employee employee = new Employee();
        model.addObject("employee", employee);
        model.setViewName("EmployeeForm");
        return model;
    }

    @RequestMapping(value = "/saveEmployee", method = RequestMethod.POST)
    public ModelAndView saveEmployee(@ModelAttribute Employee employee) {
        if (employee.getId() == 0) { // if employee id is 0 then creating the
            // employee other updating the employee
            employeeService.addEmployee(employee);
        } else {
            employeeService.updateEmployee(employee);
        }
        return new ModelAndView("redirect:/");
    }

    @RequestMapping(value = "/deleteEmployee", method = RequestMethod.GET)
    public ModelAndView deleteEmployee(HttpServletRequest request) {
        int employeeId = Integer.parseInt(request.getParameter("id"));
        employeeService.deleteEmployee(employeeId);
        return new ModelAndView("redirect:/");
    }

    @RequestMapping(value = "/editEmployee", method = RequestMethod.GET)
    public ModelAndView editContact(HttpServletRequest request) {
        int employeeId = Integer.parseInt(request.getParameter("id"));
        Employee employee = employeeService.getEmployee(employeeId);
        ModelAndView model = new ModelAndView("EmployeeForm");
        model.addObject("employee", employee);

        return model;
    }

}

pom.xml

<?xml version="1.0"?>
<!DOCTYPE project PUBLIC "-//SPRING//DTD BEAN 2.0//EN" "http://www.springframework.org/dtd/spring-beans-2.0 dtd">
<project xmlns="http://maven.apache.org/POM/4.0.0" 
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
                        http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

<groupId>com.jwt.spring</groupId>

<artifactId>SpringMVCHibernateCRUD</artifactId>

<packaging>war</packaging>

<version>1.0-SNAPSHOT</version>

<name>SpringMVCHibernateCRUD Maven Webapp</name>

<url>http://maven.apache.org</url>

<!-- Specifying the Versions of Spring, Hiberante, MySQL etc -->

<properties>
<spring.version>4.1.6.RELEASE</spring.version>
<hibernate.version>4.3.8.Final</hibernate.version>
<mssql.version>4.0</mssql.version>
<junit-version>4.11</junit-version>
<servlet-api-version>3.1.0</servlet-api-version>
<jsp-version>2.2.1</jsp-version>
<jstl-version>1.2</jstl-version>
<java.version>1.7</java.version>
</properties>

<dependencies>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>4.1.6.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>4.1.6.RELEASE</version>
<scope>test</scope>
</dependency>

<!-- Hibernate 4 dependencies -->

<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.3.8.Final</version>
</dependency>

<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-c3p0</artifactId>
<version>4.3.8.Final</version>
</dependency>

<!--MSSQL Connector -->

<dependency>
<groupId>com.microsoft.sqlserver</groupId>
<artifactId>mssql-jdbc</artifactId>
<version>6.1.0.jre8</version>
<scope>test</scope>
</dependency>

<!-- Servlet and JSP --> 

<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>

</dependency>


<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>javax.servlet.jsp-api</artifactId>
<version>2.2.1</version>
<scope>provided</scope>
</dependency>

<!-- JSTL dependency -->


<!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->



<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>

<!-- JUnit -->



<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>

</dependencies>


<build>
<finalName>SpringMVCHibernateCRUD</finalName>
<plugins>


<plugin>
<artifactId>maven-surefire-plugin</artifactId>


<configuration>


<includes>

<include>**/*Tests.java</include>

</includes>

</configuration>

</plugin>


<plugin>

<artifactId>maven-compiler-plugin</artifactId>

<version>2.3.2</version>


<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>

</plugin>

</plugins>

</build>

</project>

MvcConfiguration.java

package com.jwt;

import javax.sql.DataSource;

import com.jwt.controller.EmployeeController;
import com.jwt.dao.EmployeeDAO;
import com.jwt.dao.EmployeeDAOImpl;

import javafx.scene.control.Alert;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@ComponentScan(basePackages="com.jwt")
@EnableWebMvc

public class MvcConfiguration extends WebMvcConfigurerAdapter{

    public void demo() {
        System.out.println("in configuration...");
    }

    @Bean
    public ViewResolver getViewResolver(){
        System.out.println("in configuration...");
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/views/");
        resolver.setSuffix(".jsp");
        return resolver;

    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/resources/**").addResourceLocations("/resources/");
    }

    @Bean
    public DataSource getDataSource() {
        System.out.println("in datasoure");
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("com.microsoft.sqlserver.jdbc.SQLServerDriver");      
        dataSource.setUrl("jdbc:sqlserver://localhost:1433\\MSSQLSERVER;databaseName=Demo");
        dataSource.setUsername("gcflex_user");
        dataSource.setPassword("Gcas1234!");

        return dataSource;
    }

    @Bean
    public EmployeeDAO getContactDAO() {
        return new EmployeeDAOImpl(getDataSource());
    }

    @Bean
    public EmployeeController getEmployeeController() {
        return new EmployeeController();

    }

}

web.xml

<?xml version="1.0" encoding="ISO-8859-1" ?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
          http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    version="3.0">

    <display-name>Spring MVC Hibernate CRUD Example</display-name>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value></param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>


    <servlet>
        <servlet-name>SpringDispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextClass</param-name>
            <param-value> org.springframework.web.context.support.AnnotationConfigWebApplicationContext </param-value>
        </init-param>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>com.jwt.MvcConfiguration</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>SpringDispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>  

    <session-config>
        <session-timeout>30</session-timeout>
    </session-config>

</web-app> 

编辑:-

EmployeeService.java

package com.jwt.service;

import java.util.List;

import com.jwt.model.Employee;

public interface EmployeeService {

    public void addEmployee(Employee employee);

    public List<Employee> getAllEmployees();

    public void deleteEmployee(Integer employeeId);

    public Employee getEmployee(int employeeid);

    public Employee updateEmployee(Employee employee);
}

EmployeeServiceImpl.java

package com.jwt.service;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.jwt.dao.EmployeeDAO;
import com.jwt.model.Employee;

@Service
@Transactional
public class EmployeeServiceImpl implements EmployeeService {

    @Autowired
    private EmployeeDAO employeeDAO;

    @Override
    @Transactional
    public void addEmployee(Employee employee) {
        employeeDAO.addEmployee(employee);
    }

    @Override
    @Transactional
    public List<Employee> getAllEmployees() {
        return employeeDAO.getAllEmployees();
    }

    @Override
    @Transactional
    public void deleteEmployee(Integer employeeId) {
        employeeDAO.deleteEmployee(employeeId);
    }

    public Employee getEmployee(int empid) {
        return employeeDAO.getEmployee(empid);
    }

    public Employee updateEmployee(Employee employee) {
        // TODO Auto-generated method stub
        return employeeDAO.updateEmployee(employee);
    }

    public void setEmployeeDAO(EmployeeDAO employeeDAO) {
        this.employeeDAO = employeeDAO;
    }

}

错误日志:-

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.jwt.service.EmployeeService com.jwt.controller.EmployeeController.employeeService; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeServiceImpl': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.jwt.dao.EmployeeDAO com.jwt.service.EmployeeServiceImpl.employeeDAO; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeDAOImpl' defined in file [D:\Macron Workspace.metadata.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SpringMVCHibernateCRUD\WEB-INF\classes\com\jwt\dao\EmployeeDAOImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.jwt.dao.EmployeeDAOImpl]: No default constructor found; nested exception is java.lang.NoSuchMethodException: com.jwt.dao.EmployeeDAOImpl.() at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1202) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:755) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480) at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:663) at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:629) at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:677) at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:548) at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:489) at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136) at javax.servlet.GenericServlet.init(GenericServlet.java:158) at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1269) at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1182) at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1072) at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5362) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5660) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1700) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1690) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.jwt.service.EmployeeService com.jwt.controller.EmployeeController.employeeService; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeServiceImpl': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.jwt.dao.EmployeeDAO com.jwt.service.EmployeeServiceImpl.employeeDAO; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeDAOImpl' defined in file [D:\Macron Workspace.metadata.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SpringMVCHibernateCRUD\WEB-INF\classes\com\jwt\dao\EmployeeDAOImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.jwt.dao.EmployeeDAOImpl]: No default constructor found; nested exception is java.lang.NoSuchMethodException: com.jwt.dao.EmployeeDAOImpl.() at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:561) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331) ... 29 more Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeServiceImpl': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.jwt.dao.EmployeeDAO com.jwt.service.EmployeeServiceImpl.employeeDAO; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeDAOImpl' defined in file [D:\Macron Workspace.metadata.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SpringMVCHibernateCRUD\WEB-INF\classes\com\jwt\dao\EmployeeDAOImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.jwt.dao.EmployeeDAOImpl]: No default constructor found; nested exception is java.lang.NoSuchMethodException: com.jwt.dao.EmployeeDAOImpl.() at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1202) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194) at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1120) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1044) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:942) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:533)

Answer 1

我的建议是保持简单。

1. 从配置类中删除以下 bean 创建 -

@Bean
public EmployeeDAO getContactDAO() {
    return new EmployeeDAOImpl(getDataSource());
}

@Bean
public EmployeeController getEmployeeController() {
    return new EmployeeController();
}

使用@Controller注释 Controller 类，使用@Service注释服务，使用@Repository注释DAO。然后，您可以轻松地在其他类中 Autowiring 它们。

@Repository
public class EmployeeDAOImpl {
}

@Service
public class EmployeeService {  
    @Autowired
    private EmployeeDAO employeeDAO;
}

@Controller
public class EmployeeController {
    @Autowired
    private EmployeeService employeeService;
}

最后，对于您的 EmployeeDAOImpl 类，删除数据源的任何参数化构造函数。您也可以简单地 Autowiring 它，因为您已经在配置文件中为数据源创建了 @Bean -

@Bean
public DataSource datasource() {
    System.out.println("in datasoure");
    return dataSource;
}

@Repository
public class EmployeeDAOImpl {
    @Autowired
    private Datasource datasource;

}

这样您的问题就应该得到解决。