Spring框架：由程序员自己new个构造方法来调用对象，变成由Spring创建对象并注入相关值，直接可以使用。
使用方法：
导入Spring相关的包
1.写一个类Category
2.写一个配置文件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" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> <bean name="c" class="com.how2java.pojo.Category">//通关关键字c能获取Category对象 <property name="name" value="category 1" />//在对象获取的时候注入value的值到name中 </bean> </beans> ApplicationContext context = new ClassPathXmlApplicationContext( new String[] { "applicationContext.xml" }); Category c = (Category) context.getBean("c");原文：https://www.cnblogs.com/lspa/p/8850082.html