spring IOC控制反转与DI依赖注入

代码实现

代码结构

代码实现

User1

set方式注入
创建User1，声明name和age属性，并添加对应的setter和getter方法，以及toString方法

package cn.tedu.pojo;

public class User1 {
    private UserInfo userInfo;

    private String name ;
    private Integer age ;
    
    @Override
    public String toString() {
        return "User1{" +
                "userInfo=" + userInfo +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    public String getName() {
        return name;
    }

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

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public UserInfo getUserInfo() {
        return userInfo;
    }

    public void setUserInfo(UserInfo userInfo) {
        this.userInfo = userInfo;
    }
}

UserInfo

构造器注入
创建UserInfo，声明id和na属性，并添加有参和无参构造方法，以及toString方法

package cn.tedu.pojo;

public class UserInfo {
    private Integer id;
    private String na;

    public UserInfo() {
    }

    public UserInfo(Integer id, String na) {
        this.id = id;
        this.na = na;
    }

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

applicationContext.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
	http://www.springframework.org/schema/beans/spring-beans-4.0.xsd">

    <!-- 声明bean对象，id是唯一标志，class：bean对象的全路径 -->
    <bean id="userId" class="cn.tedu.pojo.User1">
        <!--方法一：set方式注入-->
        <!-- 通过set方式为普通属性赋值 -->
        <property name="name" value="set方式注入"></property>
        <!-- 通过set方式为对象属性赋值 -->
        <property name="userInfo" ref="userInfoId"></property>
    </bean>
    <bean id="userInfoId" class="cn.tedu.pojo.UserInfo">
        <!--方式二：构造器注入-->
        <!--通过构造器中参数为属性赋值-->
        <constructor-arg name="id" value="1"></constructor-arg>
        <constructor-arg name="na" value="构造器注入"></constructor-arg>
    </bean>
</beans>

测试类Test1

package cn.tedu;

import cn.tedu.pojo.User1;
import cn.tedu.pojo.UserInfo;
import org.junit.jupiter.api.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test1 {

    @Test
    public void test1(){
        //1.加载spring的核心配置文件
        ClassPathXmlApplicationContext ca =
                new ClassPathXmlApplicationContext("applicationContext.xml");
        //2.从spring容器中获取bean对象
        User1 user = (User1) ca.getBean("userId");
        //3.打印对象的toString方法
        System.out.println(user);

        UserInfo userInfo =(UserInfo) ca.getBean("userInfoId");
        System.out.println(userInfo);
    }
}

结果：

本文地址：https://blog.csdn.net/weixin_43187081/article/details/112018030