依赖注入-7-优快云博客

本文链接：https://blog.youkuaiyun.com/zsx1314lovezyf/article/details/127645513

依赖注入

项目结构图

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pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>thinking-in-spring</artifactId>
        <groupId>org.xiaoge</groupId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>  <!--解决依赖顺序问题, 解决依赖集成问题-->
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>ioc-container-overview</artifactId>


    <dependencies>
<!--        spring ioc 核心依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
        </dependency>
    </dependencies>

</project>

dependency-lookup-context.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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

<!--    实施加载bean-->
    <bean id="user" class="org.xiaoge.thinking.in.spring.ioc.overview.domain.User">
        <property name="id" value="1" />
        <property name="name" value="xiaoge"/>
    </bean>

    <!-- 延迟bean 是沟通objectFactory简介创建的 -->
    <bean id="objectFactory" class="org.springframework.beans.factory.config.ObjectFactoryCreatingFactoryBean">
        <property name="targetBeanName" value="user" />
    </bean>

    <!-- 延迟bean 是沟通objectFactory简介创建的 -->
    <bean id="superUser" class="org.xiaoge.thinking.in.spring.ioc.overview.domain.SuperUser" parent="user" primary="true">
        <property name="address" value="武汉" />
    </bean>

</beans>

dependency-injection-context.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:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/util https://www.springframework.org/schema/util/spring-util.xsd">

    <!--    通过导入服用 dependency-lookup-context.xml -->
    <import resource="dependency-lookup-context.xml" />

    <bean id="userRepository" class="org.xiaoge.thinking.in.spring.ioc.overview.repository.UserRepository"
    autowire="byType"> <!-- auto-wiring autowire自动绑定配置 -->
<!-- 手动配置        -->
<!--        <property name="users">-->
<!--            <util:list>-->
<!--                <ref bean="superUser" />-->
<!--                <ref bean="user" />-->
<!--            </util:list>-->
<!--        </property>-->

    </bean>


</beans>

Super注解

package org.xiaoge.thinking.in.spring.ioc.overview.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * @Classname Super
 * @Date 2022/11/1 16:06
 * @Created by ZhangXiao
 * @Description TODO
 */
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface Super {
}

User.class

package org.xiaoge.thinking.in.spring.ioc.overview.domain;

/**
 * @Classname User
 * @Date 2022/10/17 14:57
 * @Created by ZhangXiao
 * @Description TODO
 */
public class User {

    private Long id;

    private String name;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

SuperUser.class

package org.xiaoge.thinking.in.spring.ioc.overview.domain;

import org.xiaoge.thinking.in.spring.ioc.overview.annotation.Super;

/**
 * @Classname SuperUser 超级用户
 * @Date 2022/11/1 16:06
 * @Created by ZhangXiao
 * @Description TODO
 */
@Super
public class SuperUser extends User{

    private String address;

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "SuperUser{" +
                "address='" + address + '\'' +
                "} " + super.toString();
    }
}

UserRepository.class

package org.xiaoge.thinking.in.spring.ioc.overview.repository;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.context.ApplicationContext;
import org.xiaoge.thinking.in.spring.ioc.overview.domain.User;

import java.util.Collection;

/**
 * @Classname UserRepository
 * @Date 2022/11/1 16:52
 * @Created by ZhangXiao
 * @Description TODO
 */
public class UserRepository {

    private Collection<User> users; // 自定义  bean

    private BeanFactory beanFactory; // 内建 非 bean 对象 (依赖)

    private ObjectFactory<ApplicationContext> objectFactory;

    public Collection<User> getUsers() {
        return users;
    }

    public void setUsers(Collection<User> users) {
        this.users = users;
    }

    public BeanFactory getBeanFactory() {
        return beanFactory;
    }

    public void setBeanFactory(BeanFactory beanFactory) {
        this.beanFactory = beanFactory;
    }

    public ObjectFactory<ApplicationContext> getObjectFactory() {
        return objectFactory;
    }

    public void setObjectFactory(ObjectFactory<ApplicationContext> objectFactory) {
        this.objectFactory = objectFactory;
    }
}

测试类

package org.xiaoge.thinking.in.spring.ioc.overview.dependency.injection;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.xiaoge.thinking.in.spring.ioc.overview.annotation.Super;
import org.xiaoge.thinking.in.spring.ioc.overview.domain.User;
import org.xiaoge.thinking.in.spring.ioc.overview.repository.UserRepository;

import java.util.Map;

/**
 * 注意: 依赖注入/依赖查找 它们的来源并不是一个
 * 依赖注入示例 看 UserRepository
 *  1. 名称集合注入: util:list
 *  2. 类型集合注入: autowire
 *  3. 注入内部bean: users
 *  4. 注入非内建bean: BeanFactory
 *  5. 延迟注入: ObjectFactory
 *
 * @Classname DependencyInjectionDemo
 * @Date 2022/10/17 14:56
 * @Created by ZhangXiao
 * @Description TODO
 */
public class DependencyInjectionDemo {

    public static void main(String[] args) {
        // 配置xml配置文件
        // 启动spring应用上下文
        BeanFactory beanFactory = new ClassPathXmlApplicationContext("classpath:META-INF/dependency-injection-context.xml");

        UserRepository userRepository = beanFactory.getBean("userRepository", UserRepository.class);

        // 依赖注入, 注入内部bean
        System.out.println(userRepository.getUsers());

        // 依赖注入  注入非bean对象
        System.out.println(userRepository.getBeanFactory());
        System.out.println(userRepository.getBeanFactory() == beanFactory);

        // 依赖查找 (错误)
        // System.out.println(beanFactory.getBean(BeanFactory.class));

        // 延迟注入
        ObjectFactory<ApplicationContext> objectFactory = userRepository.getObjectFactory();
        System.out.println(objectFactory.getObject());

        System.out.println(objectFactory.getObject() == beanFactory);

    }


}




/*
	运行结果
		[User{id=1, name='xiaoge'}, SuperUser{address='武汉'} User{id=1, name='xiaoge'}]
		
		org.springframework.beans.factory.support.DefaultListableBeanFactory@22f71333: defining beans 			
		[user,objectFactory,superUser,userRepository]; root of factory hierarchy
		
		false
		
		org.springframework.context.support.ClassPathXmlApplicationContext@7e6cbb7a, started on Wed Nov 02 09:17:05 CST 2022
        
        true

*/