Spring autowire не удалось через несколько слоев

Question

Пока я пытаюсь разработать webapi с помощью Spring Dao, я не могу определить зависимости. Ниже приведен мой код, пожалуйста, кто-нибудь поможет мне решить эту проблему.

Структура папок проекта: -

EmployeeDAOImpl.java: -

 package com.emp.dao;

 @Repository
 public class EmployeeDAOImpl implements EmployeeDAO {

@Autowired
@Qualifier(value = "datasource")
private DataSource dataSource;

public void setDataSource(DataSource dataSource) {
    this.dataSource = dataSource;
}

@Override
public int save(Employee emp) throws Exception {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public boolean update(Employee emp) throws Exception {
    // TODO Auto-generated method stub
    return false;
}

@Override
public boolean delete(Employee emp) throws Exception {
    // TODO Auto-generated method stub
    return false;
}

@Override
public Employee findById(int id) throws Exception {
    // TODO Auto-generated method stub
    return null;
}

@Override
public List<Employee> findAll() throws Exception {
    // TODO Auto-generated method stub
    return null;
}

}

EmployeeBOImpl: -

package com.emp.business;

@Service
public class EmployeeBOImpl implements EmployeeBO{

@Autowired
EmployeeDAOImpl employeeImpl;

public void setEmployeeImpl(EmployeeDAOImpl employeeImpl) {
    this.employeeImpl = employeeImpl;
}


@Override
public int save(Employee emp) throws Exception {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public boolean update(Employee emp) throws Exception {
    // TODO Auto-generated method stub
    return false;
}

@Override
public boolean delete(Employee emp) throws Exception {
    // TODO Auto-generated method stub
    return false;
}

@Override
public Employee findById(int id) throws Exception {
    // TODO Auto-generated method stub
    return null;
}

@Override
public List<Employee> findAll() throws Exception {
    // TODO Auto-generated method stub
    return null;
}

}

EmployeeController: -

package com.emp.controller;
@Controller
public class EmployeeController{

@Autowired
private EmployeeBOImpl employeeBO;

public void setEmployeeBO(EmployeeBOImpl employeeBO) {
    this.employeeBO = employeeBO;
}
}

config.xml

<?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"
xsi:schemaLocation="http://www.springframework.org/schema/beans 
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd 
http://www.springframework.org/schema/context 
http://www.springframework.org/schema/context/spring-context-2.5.xsd">
<context:component-scan base-package="com.emp.controller" />
<context:component-scan base-package="com.emp.business" />
<context:component-scan base-package="com.emp.aop" />
<context:component-scan base-package="com.emp.dao" />
<context:annotation-config />
<bean id="datasource"    class="org.springframework.jdbc.datasource.DriverManagerDataSource"    autowire-candidate="true">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://localhost:3306/student"    />
    <property name="username" value="root" />
    <property name="password" value="password" />
    <!-- <property name="maxTotal" value="20" />
    <property name="maxIdle" value="5" /> -->
    <!-- <property name="maxWaitMillis" value="5000" /> -->
</bean>
<!-- <bean id="empController"     class="com.emp.controller.EmployeeController">

</bean> -->
</beans>

EmployeeTest.java: -

package com.emp.test;

public class EmployeeTest {

public static void main(String args[]){
    ConfigurableApplicationContext cap = new    ClassPathXmlApplicationContext("resources/config.xml");

}
 }

Исключение: -

WARNING: Exception encountered during context initialization -      cancelling refresh attempt: 

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.emp.business.EmployeeBOImpl com.emp.controller.EmployeeController.employeeBO; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeBOImpl': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.emp.dao.EmployeeDAOImpl com.emp.business.EmployeeBOImpl.employeeImpl; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeDAOImpl': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.sql.DataSource com.emp.dao.EmployeeDAOImpl.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'datasource' defined in class path resource [resources/config.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [com.mysql.jdbc.Driver]

Answer 1

Похоже, вы скучаете по mysql-connector.jar в вашем классе:

Could not load JDBC driver class [com.mysql.jdbc.Driver]

Answer 2

Вам нужно включить драйвер mysql jdbc в путь к классам. Вы можете получить банку с https://dev.mysql.com/downloads/connector/j/ или использовать зависимость Maven

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.38</version>
</dependency>

или эквивалент для вашей системы сборки.

Также избегайте классов реализации автопроводки для ваших зависимостей. Это тесно связывает ваше приложение. Вместо

 @Autowired
EmployeeDAOImpl employeeImpl;

использование

 @Autowired
EmployeeDAO employeeDao;