什么是IOC
控制反转，将对象的创建进行反转，常规情况下，对象都是开发者手动创建的，使用IOC开发者不再需要创建对象，而是由IOC容器根据需求自动创建项目所需要的对象。
相关依赖：
-
<dependency>
-
<groupId>org.springframework
</groupId>
-
<artifactId>spring-context
</artifactId>
-
<version>5.3.15
</version>
-
</dependency>
案例：
随便创建一个实体类：
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package org.example.pojo;
-
-
import lombok.Data;
-
import lombok.experimental.Accessors;
-
-
@Data
-
@Accessors(chain = true)
-
public
class
DataConfig {
-
-
private String ip;
-
-
private String dataBaseName;
-
-
private String userName;
-
-
private String pwd;
-
}
不用IOC，所有对象开发者自己创建：
测试：
-
package org.example.test;
-
-
import org.example.pojo.DataConfig;
-
-
public
class
Test {
-
public
static
void
main
(String[] args) {
-
DataConfig
dataConfig
=
new
DataConfig();
-
dataConfig.setIp(
"127.0.0.1")
-
.setDataBaseName(
"test")
-
.setUserName(
"root")
-
.setPwd(
"ok");
-
System.out.println(dataConfig);
-
}
-
}
测试结果：
使用IOC，对象不用开发者创建，而是交给Spring框架来完成：
一、基于XML：
开发者把需要的对象在XML中进行配置，Spring框架读取这个配置文件，根据配置文件的内容来创建对象。
创建一个spring.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:context=
"http://www.springframework.org/schema/context"
-
xmlns:p=
"http://www.springframework.org/schema/p"
-
xmlns:aop=
"http://www.springframework.org/schema/aop"
-
xsi:schemaLocation=
"http://www.springframework.org/schema/beans
-
https://www.springframework.org/schema/beans/spring-beans.xsd
-
http://www.springframework.org/schema/context
-
https://www.springframework.org/schema/context/spring-context.xsd
-
http://www.springframework.org/schema/aop
-
https://www.springframework.org/schema/aop/spring-aop-4.3.xsd">
-
<bean class="org.example.pojo.DataConfig" id="config">
-
<property name="ip" value="127.0.0.1" />
-
<property name="dataBaseName" value="test" />
-
<property name="userName" value="root" />
-
<property name="pwd" value="ok" />
-
</bean>
-
</beans>
测试：
-
package org.example.test;
-
-
import org.springframework.context.ApplicationContext;
-
import org.springframework.context.support.ClassPathXmlApplicationContext;
-
-
public
class
Test2 {
-
public
static
void
main
(String[] args) {
-
ApplicationContext
context
=
new
ClassPathXmlApplicationContext(
"spring.xml");
-
System.out.println(context.getBean(
"config"));
-
}
-
}
测试结果：
二、基于注解：
1、配置类
用一个Java类来替代XML文件，把在XML中配置的内容放到配置类中。
-
package org.example.configuration;
-
-
import org.example.pojo.DataConfig;
-
import org.springframework.context.annotation.Bean;
-
import org.springframework.context.annotation.Configuration;
-
-
@Configuration
-
public
class
BeanConfiguration {
-
-
@Bean(value = "config")
-
public DataConfig
dataConfig
(){
-
DataConfig
dataConfig
=
new
DataConfig();
-
dataConfig.setIp(
"127.0.0.1")
-
.setDataBaseName(
"test")
-
.setUserName(
"root")
-
.setPwd(
"ok");
-
return dataConfig;
-
}
-
}
测试：
-
package org.example.test;
-
-
import org.example.configuration.BeanConfiguration;
-
import org.springframework.context.ApplicationContext;
-
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
-
-
public
class
Test3 {
-
public
static
void
main
(String[] args) {
-
ApplicationContext
context
=
new
AnnotationConfigApplicationContext(BeanConfiguration.class);
-
System.out.println(context.getBean(
"config"));
-
}
-
}
测试结果：
2、扫包+注解
更简单的方式，不再需要依赖于XML或者配置类，而是直接将bean的创建交给目标类，在目标类添加注解来创建。
-
package org.example.pojo;
-
-
import lombok.Data;
-
import lombok.experimental.Accessors;
-
import org.springframework.beans.factory.annotation.Value;
-
import org.springframework.stereotype.Component;
-
-
@Data
-
@Component
-
@Accessors(chain = true)
-
public
class
DataConfig2 {
-
-
@Value("127.0.0.1")
-
private String ip;
-
-
@Value("test")
-
private String dataBaseName;
-
-
@Value("root")
-
private String userName;
-
-
@Value("ok")
-
private String pwd;
-
}
测试：
-
package org.example.test;
-
-
import org.example.pojo.DataConfig2;
-
import org.springframework.context.ApplicationContext;
-
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
-
-
public
class
Test4 {
-
public
static
void
main
(String[] args) {
-
ApplicationContext
context
=
new
AnnotationConfigApplicationContext(
"org.example.pojo");
-
System.out.println(context.getBean(DataConfig2.class));
-
}
-
}
测试结果：
自动创建对象，完成依赖注入。
-
package org.example.pojo;
-
-
import lombok.Data;
-
import org.springframework.beans.factory.annotation.Autowired;
-
import org.springframework.beans.factory.annotation.Value;
-
import org.springframework.stereotype.Component;
-
-
@Data
-
@Component
-
public
class
GlobalConfig {
-
@Value("8080")
-
private String port;
-
@Value("/")
-
private String path;
-
@Autowired
-
private DataConfig2 dataConfig2;
-
}
测试：
-
package org.example.test;
-
-
import org.example.pojo.GlobalConfig;
-
import org.springframework.context.ApplicationContext;
-
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
-
-
public
class
Test5 {
-
public
static
void
main
(String[] args) {
-
ApplicationContext
context
=
new
AnnotationConfigApplicationContext(
"org.example.pojo");
-
System.out.println(context.getBean(GlobalConfig.class));
-
}
-
}
测试结果：
@Autowired 通过类型进行注入，如果需要通过名称取值，通过 @Qualifier 注解完成名称的映射。
-
package org.example.pojo;
-
-
import lombok.Data;
-
import org.springframework.beans.factory.annotation.Autowired;
-
import org.springframework.beans.factory.annotation.Qualifier;
-
import org.springframework.beans.factory.annotation.Value;
-
import org.springframework.stereotype.Component;
-
-
@Data
-
@Component
-
public
class
GlobalConfig2 {
-
@Value("8080")
-
private String port;
-
@Value("/")
-
private String path;
-
@Autowired
-
@Qualifier("config")
-
private DataConfig2 dataConfig2;
-
}
测试：
-
package org.example.test;
-
-
import org.example.pojo.GlobalConfig2;
-
import org.springframework.context.ApplicationContext;
-
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
-
-
public
class
Test6 {
-
public
static
void
main
(String[] args) {
-
ApplicationContext
context
=
new
AnnotationConfigApplicationContext(
"org.example.pojo");
-
System.out.println(context.getBean(GlobalConfig2.class));
-
}
-
}
测试结果：
什么是AOP
面向切面编程，是一种抽象化的面向对象编程，对面向对象编程的一种补充，底层使用动态代理机制来实现。
相关依赖：
-
<dependency>
-
<groupId>org.springframework</groupId>
-
<artifactId>spring-aspects</artifactId>
-
<version>
5.3
.18</version>
-
</dependency>
应用场景：
打印日志、事务、权限处理
案例：
1、创建切面类
-
package org.example.aop;
-
-
import org.aspectj.lang.JoinPoint;
-
import org.aspectj.lang.annotation.AfterReturning;
-
import org.aspectj.lang.annotation.Aspect;
-
import org.aspectj.lang.annotation.Before;
-
import org.springframework.stereotype.Component;
-
-
import java.util.Arrays;
-
-
@Component
-
@Aspect
-
public
class
LoggerAspect {
-
@Before("execution(public int org.example.aop.CalImpl.*(..))")
-
public
void
before
(JoinPoint joinPoint){
-
String
name
= joinPoint.getSignature().getName();
-
System.out.println(name+
"方法的参数是"+ Arrays.toString(joinPoint.getArgs()));
-
}
-
-
@AfterReturning(value = "execution(public int org.example.aop.CalImpl.*(..))",returning = "result")
-
public
void
afterReturning
(JoinPoint joinPoint,Object result){
-
String
name
= joinPoint.getSignature().getName();
-
System.out.println(name+
"方法的结果是"+result);
-
}
-
}
2、实现类添加 @Component 注解
-
package org.example.aop;
-
-
public
interface
Cal {
-
public
int
add
(int num1, int num2);
-
public
int
sub
(int num1, int num2);
-
public
int
mul
(int num1, int num2);
-
public
int
div
(int num1, int num2);
-
}
-
package org.example.aop;
-
-
import org.springframework.stereotype.Component;
-
-
@Component
-
public
class
CalImpl
implements
Cal {
-
-
@Override
-
public
int
add
(int num1, int num2) {
-
int
result
= num1 + num2;
-
return result;
-
}
-
-
@Override
-
public
int
sub
(int num1, int num2) {
-
int
result
= num1 - num2;
-
return result;
-
}
-
-
@Override
-
public
int
mul
(int num1, int num2) {
-
int
result
= num1 * num2;
-
return result;
-
}
-
-
@Override
-
public
int
div
(int num1, int num2) {
-
int
result
= num1 / num2;
-
return result;
-
}
-
}
3、配置自动扫包，开启自动生成代理对象
-
<?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:context=
"http://www.springframework.org/schema/context"
-
xmlns:aop=
"http://www.springframework.org/schema/aop"
-
xmlns:p=
"http://www.springframework.org/schema/p"
-
xsi:schemaLocation=
"http://www.springframework.org/schema/beans
-
http://www.springframework.org/schema/beans/spring-beans.xsd
-
http://www.springframework.org/schema/context
-
http://www.springframework.org/schema/context/spring-context.xsd
-
http://www.springframework.org/schema/aop
-
http://www.springframework.org/schema/aop/spring-aop-4.3.xsd">
-
<!-- 自动扫包 -->
-
<context:component-scan base-package="org.example.aop">
</context:component-scan>
-
<!-- 开启自动生成代理 -->
-
<aop:aspectj-autoproxy>
</aop:aspectj-autoproxy>
-
</beans>
4、使用
-
package org.example.test;
-
-
import org.example.aop.Cal;
-
import org.springframework.context.ApplicationContext;
-
import org.springframework.context.support.ClassPathXmlApplicationContext;
-
-
public
class
Test7 {
-
public
static
void
main
(String[] args) {
-
ApplicationContext
context
=
new
ClassPathXmlApplicationContext(
"spring2.xml");
-
Cal
bean
= context.getBean(Cal.class);
-
System.out.println(bean.add(
9,
8));
-
System.out.println(bean.sub(
9,
8));
-
System.out.println(bean.mul(
9,
8));
-
System.out.println(bean.div(
9,
8));
-
}
-
}
测试结果：
相关视频：
【2022版】2小时学会Spring核心机制IoC和AOP_哔哩哔哩_bilibili
转载：https://blog.csdn.net/weixin_55076626/article/details/127523272
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