Spring基于的注解自动装配和依赖注入（***）

Posted 2021-02-08 贰零一八

#自动装配的小Demo:

package com.gyf.annotation;

public interface UserDao {
    public void save();
}


package com.gyf.annotation;

import org.springframework.stereotype.Repository;

@Repository("userDao")
public class UserDaoImpl implements UserDao {
    @Override
    public void save() {
        System.out.println("UserDao接口的实现类的save方法的实现...");
    }
}



package com.gyf.annotation;

public interface UserService {
     void save();
}


package com.gyf.annotation;

import org.springframework.stereotype.Service;

import javax.annotation.Resource;

@Service("userService")
public class UserServiceImpl implements UserService {
    @Resource(name = "userDao")
    private UserDao userDao;
    @Override
    public void save() {
        this.userDao.save();
        System.out.println("userservice...save...");
    }
}

 

 

#配置文件：

<?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">


   <context:component-scan base-package="com.gyf.annotation"/>
</beans>

package com.gyf.test;

import com.gyf.annotation.UserController;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class test {
    public static void main(String[] args) {
        String xmlPath="beans6.xml";
        ApplicationContext ac=new ClassPathXmlApplicationContext(xmlPath);
        UserController userController=(UserController)ac.getBean("userController");
        userController.save();
    }
}

运行结果：userController save...

 

----------------------------------------------------------------------------------------------------------------------------------------------

 

 

#依赖注入

package com.gyf.ioc;

public interface UserDao {
      void say();
}

package com.gyf.ioc;

public class UserDaoImpl implements UserDao {

    @Override
    public void say() {
        System.out.println("userDao say hello world");
    }

}

package com.gyf.ioc;

public interface UserService {
      void say();
}

package com.gyf.ioc;


public class UserServiceImpl implements UserService {
    private UserDao userDao;

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

    @Override
    public void say() {
        this.userDao.say();
        System.out.println("userService say hello world");
    }
}

 

#配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       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">

      <bean id="userDao" class="com.gyf.ioc.UserDaoImpl"/>

       <bean id="userService" class="com.gyf.ioc.UserServiceImpl">
             <property name="userDao" ref="userDao"/>
       </bean>
    
</beans>

#测试：

package com.gyf.test;

import com.gyf.ioc.UserDao;
import com.gyf.ioc.UserService;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class test {
    @Test
    public void test1(){
        ApplicationContext ac=new ClassPathXmlApplicationContext("beansIOC.xml");

        UserDao userDao=(UserDao)ac.getBean("userDao");
        userDao.say();
        UserService userService=(UserService)ac.getBean("userService");
        userService.say();
    }
}

 学会重复！

多练习，Spring 基础很重要！