POM
创建一个工程名为 spring-ioc-demo 的项目，pom.xml 文件如下：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.example</groupId><artifactId>spring-ioc-demo</artifactId><version>1.0.0-SNAPSHOT</version><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><maven.compiler.source>1.8</maven.compiler.source><maven.compiler.target>1.8</maven.compiler.target><spring.version>5.1.5.RELEASE</spring.version><lombok.version>1.16.20</lombok.version><junit.version>4.12</junit.version><log4j.version>1.2.17</log4j.version><slf4j.version>1.7.25</slf4j.version></properties><dependencies><!-- Spring Begin --><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>${spring.version}</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-test</artifactId><version>${spring.version}</version><scope>test</scope></dependency><!-- Spring End --><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>${junit.version}</version></dependency><!-- lombok Begin --><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>${lombok.version}</version><scope>provided</scope></dependency><!-- lombok End --><!-- Log Begin --><dependency><groupId>org.slf4j</groupId><artifactId>slf4j-api</artifactId><version>${slf4j.version}</version></dependency><dependency><groupId>org.slf4j</groupId><artifactId>slf4j-log4j12</artifactId><version>${slf4j.version}</version></dependency><dependency><groupId>org.slf4j</groupId><artifactId>jcl-over-slf4j</artifactId><version>${slf4j.version}</version></dependency><dependency><groupId>org.slf4j</groupId><artifactId>jul-to-slf4j</artifactId><version>${slf4j.version}</version></dependency><dependency><groupId>log4j</groupId><artifactId>log4j</artifactId><version>${log4j.version}</version></dependency><!-- Log End --></dependencies><build><plugins><!-- Compiler 插件, 设定 JDK 版本 --><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><version>3.7.0</version><configuration><source>${java.version}</source><target>${java.version}</target><encoding>${project.build.sourceEncoding}</encoding><showWarnings>true</showWarnings></configuration></plugin></plugins></build></project>核心包：主要增加了 org.springframework: spring-context 依赖
案例一，基于 xml 配置
创建 entity
java">@Data
public class Student {private int id;private String name;private String email;private String address;private Hobboy hobboy;
}java">@Data
public class Hobboy {private String basketball;private String football;private String running;
}创建 Spring 配置文件
在 src/main/resources 目录下创建 spring-context.xml 配置文件，从现在开始类的实例化工作交给 Spring 容器管理（IoC），配置文件如下：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><bean id="stu" class="com.example.spring.demo.entity.Student"><property name="id" value="10"></property><property name="name" value="vincent"></property><property name="email" value="601521821@qq.com"></property><property name="address" value="上海市、宝山区"></property><property name="hobboy" ref="hob"></property></bean><bean id="hob" class="com.example.spring.demo.entity.Hobboy"><property name="basketball" value="Nike"></property><property name="football" value="Adidas"></property><property name="running" value="5km"></property></bean></beans><bean/>：用于定义一个实例对象。一个实例对应一个 bean 元素。
id：该属性是 Bean 实例的唯一标识，程序通过 id 属性访问 Bean，Bean 与 Bean 间的依赖关系也是通过 id 属性关联的。
class：指定该 Bean 所属的类，注意这里只能是类，不能是接口
测试 Spring IoC
创建一个 GetBeanTest 测试类，测试对象是否能够通过 Spring 来创建，代码如下：
java">public class GetBeanTest {@Testpublic void testGetBean() {ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring-context.xml");Student stu = (Student) applicationContext.getBean("stu");System.out.println(stu);}
}测试结果：
Student(id=10, name=vincent, email=601521821@qq.com, address=上海市、宝山区, hobboy=Hobboy(basketball=Nike, football=Adidas, running=5km))案例一，基于注解配置
改造 entity
java">@Data
@Component
public class Student {@Value("10")private int id;@Value("Vincrnt")private String name;@Value("601521821@qq.com")private String email;@Value("上海市宝山区")private String address;@Autowiredprivate Hobboy hobboy;
}java">@Data
@Component
public class Hobboy {@Value("Nike")private String basketball;@Value("Adidas")private String football;@Value("5km")private String running;
}改造 Spring 配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><!-- 开启自动注解 --><context:annotation-config/><!-- 扫描全部的整个项目的包 --><context:component-scan base-package="com.example.spring.ioc.demo"/></beans>改造测试类 Spring IoC
java">@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:spring-context.xml")
public class GetBeanTest {@Autowiredprivate Student student;@Testpublic void annotationStu(){System.out.println(student);}}测试结果：
Student(id=10, name=vincent, email=601521821@qq.com, address=上海市、宝山区, hobboy=Hobboy(basketball=Nike, football=Adidas, running=5km))案例二，基于 xml 配置
创建 StudentService 接口
java">public interface StudentService {public void sayHi();
}创建 UserServiceImpl 实现类
java">public class StudentServiceImpl implements StudentService {public void sayHi() {System.out.println("Hello Spring IoC !!!");}
}创建 Spring 配置文件
在 src/main/resources 目录下创建 spring-context.xml 配置文件，从现在开始类的实例化工作交给 Spring 容器管理（IoC），配置文件如下：
<?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="studentService" class="com.example.spring.demo.service.impl.StudentServiceImpl" />
</beans><bean />：用于定义一个实例对象。一个实例对应一个 bean 元素。
id：该属性是 Bean 实例的唯一标识，程序通过 id 属性访问 Bean，Bean 与 Bean 间的依赖关系也是通过 id 属性关联的。
class：指定该 Bean 所属的类，注意这里只能是类，不能是接口。
测试 Spring IoC
创建一个 GetBeanTest 测试类，测试对象是否能够通过 Spring 来创建，代码如下：
java">public class GetBeanTest {@Testpublic void sayHi() {ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring-context.xml");StudentService studentServiceImpl = (StudentService) applicationContext.getBean("studentService");String sayHi = studentServiceImpl.sayHi();System.out.println(sayHi);}
}测试结果
Hello Spring IoC ！！！案例二，基于注解配置
改造实现类，加上注解 @Service
java">@Service
public class StudentServiceImpl implements StudentService {@Overridepublic String sayHi() {return "Hello Spring IoC ！！！";}
}改造 Spring 配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><!-- 开启自动注解 --><context:annotation-config/><!-- 扫描全部的整个项目的包 --><context:component-scan base-package="com.example.spring.ioc.demo"/></beans>改造测试类 Spring IoC
java">@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:spring-context.xml")
public class GetBeanTest {@Autowiredprivate StudentService studentService;@Testpublic void annotationSayHi() {String sayHi = studentService.sayHi();System.out.println(sayHi);
}测试结果：
Hello Spring IoC ！！！
