当前位置：首页 > article >正文

Spring6梳理6——依赖注入之Setter注入

article 2024/9/21 11:13:05

以上笔记来源：
尚硅谷Spring零基础入门到进阶，一套搞定spring6全套视频教程（源码级讲解）https://www.bilibili.com/video/BV1kR4y1b7Qc

一、引言

二、Java方法初始化过程

2.1 set方法及构造器方法实现Book对象初始化

三、Spring注入依赖

3.1 使用set方法进行依赖注入

3.2 使用构造器方法进行注入

四、总结

一、引言

依赖注入：

1.类有属性，创建对象过程中，向属性设置值
第一种方式：基于set方法完成
第二种方式：基于构造器完成

二、Java方法初始化过程

2.1 set方法及构造器方法实现Book对象初始化

①生成Book实体类

package com.atguigu.spring6.iocxml.bean;

public class Book {
    private String bname;
    private String author;

    public Book() {
    }

    public String getBname() {
        return bname;
    }

    public void setBname(String bname) {
        this.bname = bname;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public Book(String bname, String author) {
        this.bname = bname;
        this.author = author;
    }

    @Override
    public String toString() {
        return "Book{" +
                "bname='" + bname + '\'' +
                ", author='" + author + '\'' +
                '}';
    }

    public void run() {
        System.out.println("book run...");
    }
    public static void main(String[] args) {
        //set方法注入
        Book book=new Book();
        book.setBname("java");
        book.setAuthor("尚硅谷");
        System.out.println(book);
        //通过构造器注入
        Book book2=new Book("C++","尚硅谷");
        System.out.println(book2);
    }
}

②运行程序，如图所示

三、Spring注入依赖

3.1 使用set方法进行依赖注入

①生成Book实体类

package com.atguigu.spring6.iocxml.bean;

public class Book {
    private String bname;
    private String author;

    public Book() {
    }

    public String getBname() {
        return bname;
    }

    public void setBname(String bname) {
        this.bname = bname;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public Book(String bname, String author) {
        this.bname = bname;
        this.author = author;
    }

    @Override
    public String toString() {
        return "Book{" +
                "bname='" + bname + '\'' +
                ", author='" + author + '\'' +
                '}';
    }

    public void run() {
        System.out.println("book run...");
    }
}

②创建bean-di.xml文件

创建一个名为book的bean,并使用<property></property>标签对bean进行依赖注入

<?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">
    <!--
配置HelloWorld所对应的bean，即将HelloWorld的对象交给Spring的IOC容器管理
通过bean标签配置IOC容器所管理的bean
属性：
    id：设置bean的唯一标识
    class：设置bean所对应类的全路径
-->
        <bean id="book" class="com.atguigu.spring6.iocxml.bean.Book">
            <property name="bname" value="零基础学Java"></property>
            <property name="author" value="haozihua"></property>
        </bean>

</beans>

③ 创建测试类

package com.atguigu.spring6.iocxml.bean;

import org.junit.jupiter.api.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestBook_di {
    @Test
    public void testBook(){
        ApplicationContext context = new ClassPathXmlApplicationContext("bean-di.xml");
        Book book = context.getBean("book", Book.class);
        book.run();
        System.out.println(book);
    }
}

④运行截图如下

3.2 使用构造器方法进行注入

①生成Book实体类（如3.1所示）

②添加XML配置文件


    <!--构造方法注入-->
    <bean id="bookCon" class="com.atguigu.spring6.iocxml.bean.Book">
        <constructor-arg name="bname" value="不想学Java"></constructor-arg>
        <constructor-arg name="author" value="hhhhhh"></constructor-arg>
    </bean>

③在测试类中创建新的测试方法

    @Test
    public void testBookCon(){
        ApplicationContext context = new ClassPathXmlApplicationContext("bean-di.xml");
        Book book = context.getBean("bookCon", Book.class);
        book.run();
        System.out.println(book);
    }

④运行结果如图所示