Spring

因为之前重装系统忘记备份，放在c盘的代码和笔记(因为一般喜欢写到注释里)，全没了。再加上一年没有敲代码，只能是从0开始敲一套完整的体系了。

安装与配置

jar去这个网址下载，找最新版

下载后解压

QQ图片20210116214711

解压后差不多是这个样子：

image-20210116214923201

一堆jar

image-20210116214946140

开发简单的Spring 必须用的5个jar

spring-aop、spring-beans、spring-context、spring-core、spring-expression

以及一个日志的jar

commons-logging

创建一个Java项目作为重新开始的第一个测试项目

这里IDE选用eclipse（简单好上手），提前装好sts插件。

image-20210116215406732

编写“第一个”SpringIOC程序

创建一个applicationContext.xml

创建一个实体Student

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package top.eshyee.entity;

public class Student {
	private int stuNo;
	private String stuName;
	private int stuAge;
	public int getStuNo() {
		return stuNo;
	}
	public void setStuNo(int stuNo) {
		this.stuNo = stuNo;
	}
	public String getStuName() {
		return stuName;
	}
	public void setStuName(String stuName) {
		this.stuName = stuName;
	}
	public int getStuAge() {
		return stuAge;
	}
	public void setStuAge(int stuAge) {
		this.stuAge = stuAge;
	}
	@Override
	public String toString() {
		return "Student [stuNo=" + stuNo + ", stuName=" + stuName + ", stuAge=" + stuAge + "]";
	}	
}

在Spring的applicationcontext的xml中，创建一个bean

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<?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">

<bean id="student" class="top.eshyee.entity.Student">
<property name="stuNo" value="1"></property>
<property name="stuAge" value="2"></property>
<property name="stuName" value="genge"></property>

</bean>
</beans>

新建一个test

尝试拿取bean：

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package top.eshyee.test;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import top.eshyee.entity.Student;

public class Test1 {
	public static void main(String[] args) {
//Spring 上下文对象
		ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
		
		Student student=(Student) context.getBean("student");
		System.out.println(student);
	}
	Student getStudent1() {
		Student student = new Student();
		student.setStuName("genge");
		student.setStuNo(0);
		student.setStuAge(0);
		System.out.println(student);
		return student;
	}
}

运行结果：

Student [stuNo=1, stuName=genge, stuAge=2]