Spring6梳理6——依赖注入之Setter注入

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;}@Overridepublic 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;}@Overridepublic 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 {@Testpublic 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

    @Testpublic 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