记录Spring的ioc和aop操作

PART_ONE:IOC
Spring的ioc可以解决开发过程中New对象的操作。

1.除了导入Spring的jar包还要导入之后aop需要的jar包

image.png

2.xml配置的方式

a.简单的User.class

package entiy;

public class User {
    
    private String name;
    
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void showUser() {
        System.out.println("i am a user");
    }
}

b.Spring的核心配置文件，applicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
        http://www.springframework.org/schema/beans/spring-beans-3.2.xsd 
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd 
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.2.xsd 
        http://www.springframework.org/schema/aop 
        http://www.springframework.org/schema/aop/spring-aop-3.2.xsd 
        http://www.springframework.org/schema/tx 
        http://www.springframework.org/schema/tx/spring-tx-3.2.xsd ">
            
        <bean id="user" class="entiy.User"></bean>
        
        <bean id="userDao" class="dao.UserDaoImpl"></bean>
        
        <bean id="userSerive" class="dao.UserService">
            <property name="userDao" ref="userDao"></property>
        </bean>
        
        <!-- 开启扫描注解，对类，方法，属性上的注解进行扫描 -->
        <context:component-scan base-package="entiy,dao,aop"></context:component-scan>
                
</beans>

c.获取User实例

    @Test
    public void test() {
        //加载spring配置文件
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        
        User test = (User) context.getBean("user");
        test.showUser();
        
    }

d.bean方式配置的时候，要注意User类中是否有无参构造函数

3.ioc的注解方式实现

a.在applicationContext.xml中加入注释的支持

<bean id="userDao" class="dao.UserDaoImpl"></bean>
        
        <bean id="userSerive" class="dao.UserService">
            <property name="userDao" ref="userDao"></property>
        </bean>
        
        <!-- 开启扫描注解，对类，方法，属性上的注解进行扫描 -->
        <context:component-scan base-package="entiy,dao,aop"></context:component-scan>
        <context:component-scan base-package="cn.itcast.aop"></context:component-scan>

b.测试类
dao

public interface PersonDao {
    
    public void showName(Person person);

}

daoimp

package dao;

import org.springframework.stereotype.Component;
import org.springframework.stereotype.Repository;

import entiy.Person;

@Repository
public class PersonDaoImpl implements PersonDao{

    @Override
    public void showName(Person person) {
        System.out.println(person.getName());
        
    }


}

service

package dao;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

import entiy.Person;

@Service(value="personService")
public class PersonService {
    
    @Autowired
    private PersonDao personDao;
    
    public void showName(Person person) {
        personDao.showName(person);
    }

}

test

@Test
    public void testService() {
        //加载spring配置文件
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserService service = (UserService) context.getBean("userSerive");
        
        User test = new User();
        test.setName("handsomeboy");
        
        service.showName(test);
    }

c.四个注解的简单介绍

image.png

PART_TWO:AOP操作

AOP的四个概念

Joinpoint(连接点): 类里面可以被增强的方法，这些方法称为连接点

Pointcut(切入点):所谓切入点是指我们要对哪些Joinpoint进行拦截的定义.

Advice(通知/增强):所谓通知是指拦截到Joinpoint之后所要做的事情就是通知.通知分为前置通知,后置通知,异常通知,最终通知,环绕通知(切面要完成的功能)

Aspect(切面): 是切入点和通知（引介）的结合

Introduction(引介):引介是一种特殊的通知在不修改类代码的前提下, Introduction可以在运行期为类动态地添加一些方法或Field.
Target(目标对象):代理的目标对象(要增强的类)
Weaving(织入):是把增强应用到目标的过程.
把advice 应用到 target的过程
Proxy（代理）:一个类被AOP织入增强后，就产生一个结果代理类

1.xml配置方式实现
a.Book.class

public class Book {
    
    public void showBook() {
        System.out.println("this is a book");
    }

}

b.MyBook.class加在book的方法类

public class MyBook {
    
    public void before() {
        System.out.println("this is before");
    }

}

c.在applicationContext.xml加入aop配置

<!-- 配置aop操作 -->
        
        <bean id="book" class="aop.Book"></bean>
        <bean id="myBook" class="aop.MyBook"></bean>
        
        <aop:config>
            <!-- 配置切入点 -->
            <aop:pointcut expression="execution(* aop.Book.showBook(..))" id="bookPoint"/>
            
            <!-- 配置切面 -->
            <aop:aspect ref="myBook">
                <aop:before method="before" pointcut-ref="bookPoint"/>
            </aop:aspect>
        </aop:config> -->

d.测试

@Test
    public void test() {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        Book book = (Book) context.getBean("book");
        
        book.showBook();
    }

image.png

2.注解方式实现

a.在applicationContext.xml加入aop注解

<!-- 开启对 @Aspect 的支持-->
        <aop:aspectj-autoproxy/>

    b.myBook.class

@Aspect
public class MyBook2 {
    
    @Pointcut("execution(* aop.Book2.showBook(..))")
    public void showBook() {}
    
    @Before("showBook")
    public void before() {
        System.out.println("this is before2");
    }

}