JAVAWEB 一一 Spirng（AOP面向切面）

 

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"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-3.1.xsd "> -->
	<!-- 定义UserDao对象,并指定id为userDao -->
<!-- 	<bean id="userDao" class="dao.impl.UserDao" />
	定义UserBiz对象,并指定id为userBiz
	<bean id="userBiz" class="biz.impl.UserBiz">
		为userBiz的dao属性赋值,需要注意的是,这里要调用setDao()方法
		<property name="dao">
			引用id为userDao的对象为userBiz的dao属性赋值
			<ref bean="userDao" />
			<bean class="dao.impl.UserDao"></bean>
		</property>
		<property name="num">
			<value>10</value>
		</property>
	</bean> -->
	
<!-- 	<bean id="userDao1" class="com.demo.dao.UserDaoImpl"></bean>
	<bean id="userService" class="service.UserServiceImpl">
		<property name="userDao">
			<ref bean="userDao1"/>
		</property>		
	</bean>  -->
	
<!-- 	<bean id="userDao" class="com.demo.dao.UserDaoImpl"></bean>
	<bean id="userService" class="service.UserServiceImpl">
		<constructor-arg>
			<ref bean ="userDao"/>
		</constructor-arg>	
	</bean> -->
<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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans 
           http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-3.1.xsd
           http://www.springframework.org/schema/aop
           http://www.springframework.org/schema/aop/spring-aop-3.1.xsd">
	<bean id="userService" class="com.aop.service.UserService"/>
	<bean id="servicelogging" class="com.aop.service.ServiceLogging"/>
		<aop:config>
			<aop:pointcut expression="execution(public * com.aop.service.*.*Service(..))" id="servicePointcut"/>
			<aop:aspect ref="servicelogging">
				<aop:before method="before" pointcut-ref="servicePointcut"/>
				<aop:after method="after" pointcut-ref="servicePointcut"/>
				<aop:after-returning method="afterReturing" pointcut-ref="servicePointcut"/>
				<aop:after-throwing method="afterThrowing" pointcut-ref="servicePointcut"/>
				<aop:around method="around" pointcut-ref="servicePointcut"/>				
			</aop:aspect>
		</aop:config>
</beans>

　　User.java

package com.aop.entity;

public class User {
	private int id;
	private String username;
	private String password;
	private String email;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public User(int id, String username, String password, String email) {
		super();
		this.id = id;
		this.username = username;
		this.password = password;
		this.email = email;
	}
	public User() {
		super();
		// TODO Auto-generated constructor stub
	}
	
}

　　UserService

package com.aop.service;

import com.aop.entity.User;

public class UserService {

	/**
	 * @param args
	 */
	public void addUserService(User user){
		
		System.out.println("业务方法被执行");
		System.out.println(user.getUsername());

	}

}

　　ServiceLogging

package com.aop.service;

import org.aspectj.lang.ProceedingJoinPoint;

public class ServiceLogging {
	public void before(){
		System.out.println("前置增强处理被执行");
	}
	public void after(){
		System.out.println("最终增强处理被执行");
	}
	public void afterReturing(){
		System.out.println("后置增强处理被执行");
	}
	public void afterThrowing(){
		System.out.println("抛异常增强处理被执行");
	}
	
	public void around(ProceedingJoinPoint pjp){
		System.out.println("环绕前置增强处理被执行");
		try {
			pjp.proceed();
		} catch (Throwable e) {
			
			e.printStackTrace();
		}
		System.out.println("环绕后置增强处理被执行");
	}
}

　　AopTest.java

package com.aop.test;

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

import com.aop.entity.User;
import com.aop.service.UserService;

public class AopTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
		 UserService service=(UserService)ctx.getBean("userService");
		 User user = new User(10,"Tom","123456","504177380@qq.com");
		 service.addUserService(user);
		
		
	}

}

　　

Spring的本质是什么？

1.对象的创建

 new  抽象类 工厂模式 

工厂模式，以及其他模式像抽象工厂，

Builder模式提供的都是创建对象的方法。
这背后体现的都是“封装变化”的思想。 

这些模式只是一些最佳实践而已： 起了一个名称、描述一下解决的问题、使用的范围和场景，在项目中还得自己去编码实现他们。

2.解除依赖

面向接口编程

3.Spring依赖注入

在Java 世界里，如果想描述各种逻辑关系， XML是不二之选

这个xml 挺容易理解的， 但是仅仅有它还不够， 还缺一个解析器（假设叫做XmlAppContext）来解析，处理这个文件，

基本过程是：0. 解析xml, 获取各种元素

　　　　　　1. 通过Java反射把各个bean 的实例创建起来：

　　　　　　2. 还是通过Java反射调用 的两个方法：

ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService service=(UserService)ctx.getBean("userService");

4.IOC VS DI