Spring 注解装配

创建依赖关系:UserDao,UserAction,UserService
UserDao:

package zhujie;
import org.springframework.stereotype.Component;
@Component("userDao")
public class UserDao {
	public void  add() {
		System.out.println("连接数据库成功，并已添加用户");
	}
}

UserService:

package zhujie;
import javax.annotation.Resource;
import org.springframework.stereotype.Component;
@Component("userService")
public class UserService {
	@Resource(name="userDao")
	private UserDao userDao;
	public void add() {
		userDao.add();
	}
}

UserAction:

package zhujie;
import javax.annotation.Resource;
import org.springframework.stereotype.Component;
@Component("userAction")
public class UserAction {
	@Resource(name="userService")
	private  UserService userService;
	public String addUser() {
		userService.add();
		return null;
	}
}

app.xml配置:
切记是开启对应的包扫描：<context:component-scan base-package="对应的包名"></context:component-scan>

<?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"
       xmlns:p="http://www.springframework.org/schema/p" 
       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-4.3.xsd">
		<!-- 开启base-package 扫描 -->
		<context:component-scan base-package="zhujie"></context:component-scan>
</beans>

测试类:

@Test
	public void app() {
		ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("app.xml");
		UserAction	userAction = (UserAction) applicationContext.getBean("userAction");
		userAction.addUser();
	}

-------------------------------------------优化------------------------------------------------------------
为了分清楚层次结构：
注解可以对应相应的层次：
如下:
持久层：

package zhujie;
import org.springframework.stereotype.Repository;
@Repository//持久层
public class UserDao {
	public void  add() {
		System.out.println("连接数据库成功，并已添加用户");
	}
}

控制层：

package zhujie;
import javax.annotation.Resource;
import org.springframework.stereotype.Controller;
@Controller//控制层
public class UserAction {
	@Resource(name="userService")
	private  UserService userService;
	public String addUser() {
		userService.add();
		return null;
	}
}

控制层下的service层：

package zhujie;
import javax.annotation.Resource;
import org.springframework.stereotype.Service;
@Service//控制层下的service层
public class UserService {
	@Resource(name="userDao")
	private UserDao userDao;
	public void add() {
		userDao.add();
	}
}

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