工程的目录结构以及所需的jar包如下:
1.beans.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.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<!-- The implicitly registered post-processors include AutowiredAnnotationBeanPostProcessor, CommonAnnotationBeanPostProcessor,PersistenceAnnotationBeanPostProcessor, as well as the aforementioned RequiredAnnotationBeanPostProcessor.-->
<context:annotation-config/>
<bean name="userDao1" class="com.bjsxt.dao.impl.UserDAOImpl"></bean>
<bean name="userDao2" class="com.bjsxt.dao.impl.UserDAOImpl"></bean>
<bean name="userService" class="com.bjsxt.service.UserService"></bean>
</beans>
2.接口UserDao
package com.bjsxt.dao;
import com.bjsxt.model.User;
public interface UserDAO {
public void save(User user);
}
3.接口的实现UserDaoImpl
package com.bjsxt.dao.impl;
import com.bjsxt.dao.UserDAO;
import com.bjsxt.model.User;
public class UserDAOImpl implements UserDAO {
public void save(User user) {
System.out.println("test--------"+user.getUsername());
System.out.println("user saved!");
}
}
4.编写数据传输User类
package com.bjsxt.model;
public class User {
private String username;
private String password;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
5.UserService
package com.bjsxt.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import com.bjsxt.dao.UserDAO;
import com.bjsxt.model.User;
public class UserService {
private UserDAO userDAO;
public void add(User user) {
userDAO.save(user);
}
public UserDAO getUserDAO() {
return userDAO;
}
/*首先按名称来注入,由于没有名为"userDAO"的bean。所以采用类型来注入,但是com.bjsxt.dao.UserDAO类型的bean有2个,所以会报错。
*处理:搭配@Qualifier来使用,指定注入userDao1,userDao2中那个bean
*/
@Autowired
@Qualifier("userDao2") //指定注入userDao2
public void setUserDAO(UserDAO userDAO) {
this.userDAO = userDAO;
}
}
6.编写测试类UserServiceTest
package com.bjsxt.service;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.bjsxt.model.User;
public class UserServiceTest {
@Test
public void testAdd() {
/**ApplicationContext是建立在BeanFactory之上的,BeanFactory它只是完成了Bean工厂的一些功能,像Bean的声明周期它都处理不了。而ApplicationContext除了能完成BeanFactory所有的功能之外,还能够完成 一些其他的附加的功能,比如说bean的声明的周期。
*/
ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
UserService service = (UserService)ctx.getBean("userService");
User u = new User();
u.setUsername("zhangsan");
u.setPassword("gaoweigang");
service.add(u);
}
}