Spring课程 Spring入门篇 3-4 Spring bean装配（上）之自动装配

课程链接：

1　　　　自动装配的方式

2　　　　自动装配实现

1　　　　自动装配的方式

根据反射的机制

1.1　　byName根据属性名自动装配，类似于依赖注入的set注入。（如果找不到set属性中的bean，如果test中用try方法的话，报空指针异常）

1.2　　byType根据类名进行注入，xml配置文件beanId可以不用写

1.3　　constructor应用于构造器参数。（找不到构造器参数一致的bean，抛异常）

2　　　　自动装配实现

2.1　　自动装配byName：

该方式实现方式与set注入类似，唯一不同之处见xml配置文件红色部分

实体类：

package com.imooc.autowiring;

public class AutoWiringDaoImpl implements AutoWiringDao{

    @Override

    public void say(String word) {

        // TODO Auto-generated method stub

        System.out.println("请你说话："+word);

    }

}

接口（与set注入相同）：

package com.imooc.autowiring;

public class AutoWiringService {

    private AutoWiringDao autoWiringDao;

    public void setAutoWiringDao(AutoWiringDao autoWiringDao) {

        this.autoWiringDao = autoWiringDao;

    }

    public void sayHello(String word){

        autoWiringDao.say(word);

    }

}

xml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"

default-autowire="byName">

<bean id="autoWiringService" class="com.imooc.autowiring.AutoWiringService">

<!--     <property name="autoWiringDao" ref="autoWiringDao"></property>     -->

</bean>

<bean id="autoWiringDao" class="com.imooc.autowiring.AutoWiringDaoImpl"></bean> 

</beans>

测试文件：

package com.imooc.autowiring;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.junit.runners.BlockJUnit4ClassRunner;

import com.imooc.test.base.UnitTestBase;

@RunWith(BlockJUnit4ClassRunner.class)

public class TestAutoWiring extends UnitTestBase{

    public TestAutoWiring() {

        super("classpath:spring-autowiring.xml");

        // TODO Auto-generated constructor stub

    }

    @Test

    public void testAutoWiring(){

        try {

            AutoWiringService aws = super.getbean("autoWiringService");

            aws.sayHello("老婆好！");

        } catch (Exception e) {

            // TODO: handle exception

            e.printStackTrace();

        }

    }

}

打印结果

三月 02, 2019 6:51:24 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh

信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@652c4193: startup date [Sat Mar 02 06:51:24 CST 2019]; root of context hierarchy

三月 02, 2019 6:51:24 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

信息: Loading XML bean definitions from class path resource [spring-autowiring.xml]

请你说话：老婆好！

三月 02, 2019 6:51:25 上午 org.springframework.context.support.ClassPathXmlApplicationContext doClose

信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@652c4193: startup date [Sat Mar 02 06:51:24 CST 2019]; root of context hierarchy

2.2　　自动装配byType（其他文件与byName完全一致，只有xml配置文件不同）

xml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"

default-autowire="byType">

<bean id="autoWiringService" class="com.imooc.autowiring.AutoWiringService">

</bean>

<bean id="autoWiringDao111" class="com.imooc.autowiring.AutoWiringDaoImpl"></bean> 

</beans>

打印结果

三月 02, 2019 6:51:24 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh

信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@652c4193: startup date [Sat Mar 02 06:51:24 CST 2019]; root of context hierarchy

三月 02, 2019 6:51:24 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

信息: Loading XML bean definitions from class path resource [spring-autowiring.xml]

请你说话：老婆好！

三月 02, 2019 6:51:25 上午 org.springframework.context.support.ClassPathXmlApplicationContext doClose

信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@652c4193: startup date [Sat Mar 02 06:51:24 CST 2019]; root of context hierarchy

2.3　　constructor（类似于构造依赖注入法）

实体类：

package com.imooc.autowiring;

public class AutoWiringService {

    private AutoWiringDao autoWiringDao;

//    public void setAutoWiringDao(AutoWiringDao autoWiringDao) {

//        this.autoWiringDao = autoWiringDao;

//    }

    public AutoWiringService(AutoWiringDao autoWiringDao) {

        this.autoWiringDao = autoWiringDao;

    }

    public void sayHello(String word){

        autoWiringDao.say(word);

    }

    public AutoWiringService() {

        super();

        // TODO Auto-generated constructor stub

    }

}

xml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"

default-autowire="constructor">

<bean id="autoWiringService" class="com.imooc.autowiring.AutoWiringService">

</bean>

<bean id="autoWiringDao111" class="com.imooc.autowiring.AutoWiringDaoImpl"></bean> 

</beans>

测试类：

package com.imooc.autowiring;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.junit.runners.BlockJUnit4ClassRunner;

import com.imooc.test.base.UnitTestBase;

@RunWith(BlockJUnit4ClassRunner.class)

public class TestAutoWiring extends UnitTestBase{

    public TestAutoWiring() {

        super("classpath:spring-autowiring.xml");

        // TODO Auto-generated constructor stub

    }

    @Test

    public void testAutoWiring(){

        try {

            AutoWiringService aws = super.getbean("autoWiringService");

            aws.sayHello("老婆好！");

        } catch (Exception e) {

            // TODO: handle exception

            e.printStackTrace();

        }

    }

}

巴特西

Spring课程 Spring入门篇 3-4 Spring bean装配（上）之自动装配

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