1、建立文件

1.1、cat类

public class Cat {
    public void shout() {
        System.out.println("miaomiaomiao~");
    }
}

1.2、dog类

public class Dog {
    public void shout() {
        System.out.println("wangwangwang~");
    }

}

1.3、Person类

public class Person {
    private Dog dog;
    private Cat cat;
    private String name;

    Person(){

    }

    Person(String name){
        this.name = name;
    }

    public Dog getDog() {
        return dog;
    }

    public void setDog(Dog dog) {
        this.dog = dog;
    }

    public Cat getCat() {
        return cat;
    }

    public void setCat(Cat cat) {
        this.cat = cat;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

1.4、MyTest类客户端代码

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("ApplicationContext.xml");
        Person person = context.getBean("person", Person.class);
        person.getCat().shout();
        person.getDog().shout();
    }
}

1.5、ApplicationContext.xml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:p="http://www.springframework.org/schema/p"
       xmlns:c="http://www.springframework.org/schema/c"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="dog" class="com.bubaiwantong.CP.Dog"/>
    <bean id="cat" class="com.bubaiwantong.CP.Cat"/>
    <!--1、传统方式注入-->
    <bean id="person" class="com.bubaiwantong.CP.Person">
        <property name="name" value="小明"/>
        <property name="cat" ref="cat"/>
        <property name="dog" ref="dog"/>
    </bean>
</beans>

2、C命名空间注入

这里的C代表的Constructor，比一般的注入少许多代码。

<?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:p="http://www.springframework.org/schema/p"
       xmlns:c="http://www.springframework.org/schema/c"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="dog" class="com.bubaiwantong.CP.Dog"/>
    <bean id="cat" class="com.bubaiwantong.CP.Cat"/>
    <!--2、c命名空间注入-->
    <bean id="person" class="com.bubaiwantong.CP.Person" c:name="小明"/>
</beans>

3、P命名空间注入

这里的P是Properties的简写，和C命名空间类似，这俩这种方式都是为了简化代码。

<?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:p="http://www.springframework.org/schema/p"
       xmlns:c="http://www.springframework.org/schema/c"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="dog" class="com.bubaiwantong.CP.Dog"/>
    <bean id="cat" class="com.bubaiwantong.CP.Cat"/>
    <!--2、p命名空间注入-->
    <bean id="person" class="com.bubaiwantong.CP.Person" p:name="小明" p:cat-ref="cat" p:dog-ref="dog"></bean>
</beans>

4、autowired的自动注入

4.1、ByName注入

<?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:p="http://www.springframework.org/schema/p"
       xmlns:c="http://www.springframework.org/schema/c"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="dog" class="com.bubaiwantong.CP.Dog"/>
    <bean id="cat" class="com.bubaiwantong.CP.Cat"/>

    <!--autowired注入，通过name注入，要求对象名唯一，否则会报错-->
    <bean id="person" class="com.bubaiwantong.CP.Person" autowire="byName"/>
</beans>

4.2、ByType注入

<?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:p="http://www.springframework.org/schema/p"
       xmlns:c="http://www.springframework.org/schema/c"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="dog" class="com.bubaiwantong.CP.Dog"/>
    <bean id="cat" class="com.bubaiwantong.CP.Cat"/>

    <!--autowired注入，通过name注入，要求对象名唯一，否则会报错-->
    <bean id="person" class="com.bubaiwantong.CP.Person" autowire="byType"/>
</beans>