注解实现自动装配

• 配置
• @Autowired与@Qualifier

配置

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">

        <context:annotation-config/>
</beans>

@Autowired与@Qualifier

$1.$ 将@Autowired加在实体类的属性上面，可以自动通过属性名或属性类型来自动装配；
$2.$ 如果@Autowired自动装配的环境比较复杂，自动装配无法通过一个注解@Autowired完成的时候，我们可以使用@Qualifier(value = “xxx”)去配置@Autowired的使用，指定一个唯一的bean对象注入；
$3.$ 使用@Autowired后就不需要set方法了。

package com.tl.pojo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;

/**
 * @author tl
 */
public class People {
    private String name;
    @Autowired
    @Qualifier(value = "dog22")
    private Dog dog;
    @Autowired
    private Cat cat;

    public People() {
    }

    public String getName() {
        return name;
    }

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

    public Dog getDog() {
        return dog;
    }


    public Cat getCat() {
        return cat;
    }

}

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">

        <context:annotation-config/>
    <bean id="cat11" class="com.tl.pojo.Cat"/>
    <bean id="dog22" class="com.tl.pojo.Dog"/>
    <bean id="dog23" class="com.tl.pojo.Dog"/>
    <bean id="people" class="com.tl.pojo.People">
        <property name="name" value="tl"/>
<!--        <property name="cat" ref="cat"/>-->
<!--        <property name="dog" ref="dog"/>-->
    </bean>
</beans>