依赖注入就是对类的属性进行赋值

4.1、环境搭建

创建名为spring_ioc_xml的新module，过程参考3.1节

4.1.1、创建spring配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

</beans>

4.1.2、创建学生类Student

package org.rain.spring.pojo;

/**
 * @author liaojy
 * @date 2023/7/27 - 22:33
 */
public class Student {

    private Integer id;
    private String name;
    private Integer age;
    private String sex;

    public Student() {
    }

    public Student(Integer id, String name, Integer age, String sex) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.sex = sex;
    }

    public Integer getId() {
        return id;
    }

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

    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 String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

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

4.2、setter注入(常用)

4.2.1、配置bean

    <!--
        property标签:通过组件类的setXxx()方法给组件对象设置属性
            name属性：指定属性名
            value属性：设置属性值
    -->
    <bean id="student" class="org.rain.spring.pojo.Student">
        <property name="id" value="0011"></property>
        <property name="name" value="张三"></property>
        <property name="age" value="23"></property>
        <property name="sex" value="男"></property>
    </bean>

4.2.2、测试

package org.rain.spring.test;

import org.junit.Test;
import org.rain.spring.pojo.Student;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @author liaojy
 * @date 2023/7/27 - 22:43
 */
public class IOCByXmlTest {

    @Test
    public void testDISetter(){
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring-ioc.xml");
        Student student = applicationContext.getBean("student", Student.class);
        System.out.println(student);
    }
}

4.3、构造器注入

4.3.1、配置bean

注意：constructor-arg标签的数量，必须和某一个构造器方法的参数数量一致

    <!--
        constructor标签：通过组件类的有参构造方法给组件对象设置属性
            name属性：指定有参构造方法参数名
            value属性：设置有参构造方法参数值
    -->
    <bean id="studentTwo" class="org.rain.spring.pojo.Student">
        <constructor-arg name="id" value="1002"></constructor-arg>
        <constructor-arg name="name" value="李四"></constructor-arg>
        <constructor-arg name="age" value="24"></constructor-arg>
        <constructor-arg name="sex" value="女"></constructor-arg>
    </bean>

4.3.2、测试

    @Test
    public void testDIConstructor(){
        ApplicationContext appli