java 创建名为“employeeController”的 bean 时出错：注入自动装配的依赖项失败
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StackOverFlow
Error creating bean with name 'employeeController': Injection of autowired dependencies failed
提问by Bhavin
I tried for Configuration with MvcConfiguration.java as Dispatcher file.But it throw errors while creating bean for controller and DAO file.
我尝试使用 MvcConfiguration.java 作为 Dispatcher 文件进行配置。但是它在为控制器和 DAO 文件创建 bean 时抛出错误。
I know there are lots of question regarding this error on stackoverflow. But I'm not able to solve and stuck in it.
我知道在 stackoverflow 上有很多关于这个错误的问题。但我无法解决并陷入困境。
Following are files in which I found below errors.
以下是我发现以下错误的文件。
EmployeeController.java
员工控制器.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
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
配置文件
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
网页.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>
EDIT :-
编辑 ：-
EmployeeService.java
员工服务.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
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;
}
}
Error Log :-
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)
org.springframework.beans.factory.BeanCreationException：创建名为“employeeController”的 bean 时出错：自动装配依赖项的注入失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException：无法自动装配字段：私有 com.jwt.service.EmployeeService com.jwt.controller.EmployeeController.employeeService; 嵌套异常是 org.springframework.beans.factory.BeanCreationException：创建名为“employeeServiceImpl”的 bean 时出错：自动装配依赖项的注入失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException：无法自动装配字段：private com.jwt.dao.EmployeeDAO com.jwt.service.EmployeeServiceImpl.employeeDAO；嵌套异常是 org.springframework.beans.factory.BeanCreationException：创建名为“employeeDAOImpl”的 bean 在文件 [D:\Macron Workspace.metadata.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SpringMVCHibernateCRUD\WEB-INF\classes\com\jwt\dao\ 中定义时出错EmployeeDAOImpl.class]：bean实例化失败；嵌套异常是 org.springframework.beans.BeanInstantiationException：无法实例化 [com.jwt.dao.EmployeeDAOImpl]：未找到默认构造函数；嵌套异常是 java.lang.NoSuchMethodException: com.jwt.dao.EmployeeDAOImpl.() 在 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334) 在 org.springframework.supportbeansfactory .AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1202) 在 org.springframework.beans.factory。concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) 引起：org.springframework.beans.factory.BeanCreationException：无法自动装配字段：private com.jwt.service.EmployeeService com.jwt.controller.EmployeeController.employeeService; 嵌套异常是 org.springframework.beans.factory.BeanCreationException：创建名为“employeeServiceImpl”的 bean 时出错：自动装配依赖项的注入失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException：无法自动装配字段：private com.jwt.dao.EmployeeDAO com.jwt.service.EmployeeServiceImpl.employeeDAO；嵌套异常是 org.springframework.beans.factory.BeanCreationException：创建名为“employeeDAOImpl”的 bean 在文件 [D:\Macron Workspace.metadata.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SpringMVCHibernateCRUD\WEB-INF\classes\com\jwt\dao\ 中定义时出错EmployeeDAOImpl.class]：bean实例化失败；嵌套异常是 org.springframework.beans.BeanInstantiationException：无法实例化 [com.jwt.dao.EmployeeDAOImpl]：未找到默认构造函数；嵌套异常是 java.lang.NoSuchMethodException: com.jwt.dao.EmployeeDAOImpl.() 在 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:561) 在 org.springframework.beansfactoryyyyy .annotation.InjectionMetadata.inject(InjectionMetadata.java:88) 在 org.springframework.beans.factory.annotation。AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331) ... 29 更多 原因：org.springframework.beans.factory.BeanCreationException：创建名为“employeeServiceImpl”的 bean 时出错：自动装配依赖项的注入失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException：无法自动装配字段：private com.jwt.dao.EmployeeDAO com.jwt.service.EmployeeServiceImpl.employeeDAO；嵌套异常是 org.springframework.beans.factory.BeanCreationException：在文件 [D:\Macron Workspace.metadata.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\SpringMVCHibernateCRUD 中定义的名称为“employeeDAOImpl”的 bean 创建时出错\WEB-INF\classes\com\jwt\dao\EmployeeDAOImpl.class]：bean实例化失败；嵌套异常是 org.springframework.beans.BeanInstantiationException：无法实例化 [com.jwt.dao.EmployeeDAOImpl]：未找到默认构造函数；嵌套异常是 java.lang.NoSuchMethodException: com.jwt.dao.EmployeeDAOImpl.() 在 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334) 在 org.springframework.supportbeansfactory .AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1202) 在 org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537) 在 org.springframework.beans.tractfactory.support. :476) 在 org.
回答by Saharsh Singh
@Autowired
private EmployeeService employeeService;
This is the issue. I see a dependency for EmployeeService in your controller implementation, but you did not paste the EmployeeService class definition here. Does this class exist and is there a bean being defined for it? The controller bean is expecting this bean to be injected by Spring, but Spring is not able to find it in the application context, since it does not exist, and hence the exception.
这就是问题。我在您的控制器实现中看到 EmployeeService 的依赖项，但您没有在此处粘贴 EmployeeService 类定义。这个类是否存在并且是否为它定义了一个 bean？控制器 bean 期望 Spring 注入这个 bean，但 Spring 无法在应用程序上下文中找到它，因为它不存在，因此出现异常。
回答by gohil90
My suggestion would be keep it simple.
我的建议是保持简单。
- Remove below bean creation from configuration class -
- 从配置类中删除下面的 bean 创建 -
@Bean public EmployeeDAO getContactDAO() { return new EmployeeDAOImpl(getDataSource()); } @Bean public EmployeeController getEmployeeController() { return new EmployeeController(); }
@Bean public EmployeeDAO getContactDAO() { return new EmployeeDAOImpl(getDataSource()); } @Bean public EmployeeController getEmployeeController() { return new EmployeeController(); }
- Annotate controller class with @Controller, service with @Service & DAO with @Repository. Then, you can easily autowire them in other class.
- 用@Controller 注释控制器类，用@Service 注释服务，用@Repository 注释DAO。然后，您可以轻松地在其他类中自动装配它们。
@Repository public class EmployeeDAOImpl { } @Service public class EmployeeService { @Autowired private EmployeeDAO employeeDAO; } @Controller public class EmployeeController { @Autowired private EmployeeService employeeService; }
@Repository public class EmployeeDAOImpl { } @Service public class EmployeeService { @Autowired private EmployeeDAO employeeDAO; } @Controller public class EmployeeController { @Autowired private EmployeeService employeeService; }
- Lastly, for your EmployeeDAOImpl class, remove any parameterized constructor you have for datasource. You can simply autowire that too as you have created @Bean for datasource in configuration file -
- 最后，对于 EmployeeDAOImpl 类，删除数据源的任何参数化构造函数。您也可以简单地自动装配它，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; }
@Bean public DataSource datasource() { System.out.println("in datasoure"); return dataSource; } @Repository public class EmployeeDAOImpl { @Autowired private Datasource datasource; }
This way your issue should get fixed.
这样你的问题应该得到解决。
