Spring自动装配

applocationContext.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"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/aop
        https://www.springframework.org/schema/aop/spring-aop.xsd"
>
    <context:annotation-config/>
    <!--
        如果设置了byName 的话会直接找 id
        如果设置了byType 的话会直接找 class属性所对应的类名
    -->
    <bean id="dog" class="com.rzk.pojo.Dog"></bean>
    <bean id="cat" class="com.rzk.pojo.Cat"></bean>
    <!--
        byName: 会自动在容器上下文查找，和自己对象set方法后面的值对应的 bean id
        byType: 会自动在容器上下文查找，和自己对象属性类名相同的bean
    -->
    <bean id="people" class="com.rzk.pojo.People" autowire="byName">
　 　<bean id="people" class="com.rzk.pojo.People" autowire="byType">

    </bean>
</beans>

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

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

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

    public Cat getCat() {
        return cat;
    }

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

    public Dog getDog() {
        return dog;
    }

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

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "People{" +
                "cat=" + cat +
                ", dog=" + dog +
                ", name='" + name + '\'' +
                '}';
    }
}

测试类
public class MyTest {
    @Test
    public void test(){
        ApplicationContext context = new ClassPathXmlApplicationContext("applocationContext.xml");
        People people = context.getBean("people", People.class);
        people.getCat().shout();
        people.getDog().shout();
    }
}

 

自动转配：autowire
1) autowire="byType" 根据类型，自动导入需要的类属性，如果定义的类属性是单个，导入的类属性有>=2个类实例,报错
如果定义的类属性是集合，导入的类属性有>=2个类实例没问题
2) autowire="byName" 根据类中定义的类属性的名字，如果bean中有>=2的类属性的实例，报错

byName: 会自动在容器上下文查找，和自己对象set方法后面的值对应的 bean id
byType: 会自动在容器上下文查找，和自己对象属性类名相同的bean

 

byName: 会自动在容器上下文查找，和自己对象set方法后面的值对应的 bean id
byType: 会自动在容器上下文查找，和自己对象属性类名相同的bean