Spring的AOP注解编程

XML

1、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.xsd"><!--  1. 默认情况下, IOC 容器中的 bean 是单例的! 若对象是单例的, 则在创建 IOC 容器时即创建 bean 的实例, 并对 bean 的属性进行初始化. 2. 可以通过 bean 的 scope 属性来修改 bean 的作用域. 若取值为 prototype, 则 bean 为原型的: 每次向容器获取实例, 得到的都是一个新的对象.而且, 不在创建 IOC 容器时创建 bean 的实例了. 3. IOC 容器中 bean 的生命周期: 3.1 一般地, 讨论 bean 的生命周期, 是建立在 bean 是单例的基础上的. 3.2 可以为 bean 指定 init 和 destroy 方法3.3 还可以通过 bean 的后置处理器来更加丰富 bean 的生命周期方法(面试时.).--><bean id="helloWorld" class="com.atguigu.spring.helloworld.HelloWorld" scope="singleton"init-method="init"destroy-method="destroy"><property name="userName" value="atguigu"></property></bean><!--  1. 在 IOC 容器中配置 bean 之间的关联关系--><bean id="userDao"class="com.atguigu.spring.ref.UserDao"></bean><bean id="userService"class="com.atguigu.spring.ref.UserService"><property name="userDao" ref="userDao"></property></bean><bean id="userAction" class="com.atguigu.spring.ref.UserAction"><property name="userService" ref="userService"></property></bean></beans>

2、applicationContext-aop.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:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"><!-- 自动扫描的包 --><context:component-scan base-package="com.atguigu.spring.aop"></context:component-scan><!-- 使 AspectJ 的注解起作用 --><aop:aspectj-autoproxy></aop:aspectj-autoproxy></beans>

3、applicationContext-annotation.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"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"><!-- 配置自动扫描的包 --><context:component-scan base-package="com.atguigu.spring.ref"></context:component-scan></beans>

Java

1、com.atguigu.spring.aop包

1）ArithmeticCalculator.java

package com.atguigu.spring.aop;public interface ArithmeticCalculator {int add(int i, int j);int sub(int i, int j);int mul(int i, int j);int div(int i, int j);}

2）ArithmeticCalculatorImpl.java

package com.atguigu.spring.aop;import org.springframework.stereotype.Component;@Component("arithmeticCalculator")public class ArithmeticCalculatorImpl implements ArithmeticCalculator {@Overridepublic int add(int i, int j) {int result = i + j;return result;}@Overridepublic int sub(int i, int j) {int result = i - j;return result;}@Overridepublic int mul(int i, int j) {int result = i * j;return result;}@Overridepublic int div(int i, int j) {int result = i / j;return result;}}

3）ArithmeticCalculatorLoggingImpl.java

package com.atguigu.spring.aop;public class ArithmeticCalculatorLoggingImpl implements ArithmeticCalculator {@Overridepublic int add(int i, int j) {System.out.println("The method add begins with [" + i + "," + j + "]");int result = i + j;System.out.println("The method add ends with " + result);return result;}@Overridepublic int sub(int i, int j) {System.out.println("The method sub begins with [" + i + "," + j + "]");int result = i - j;System.out.println("The method sub ends with " + result);return result;}@Overridepublic int mul(int i, int j) {System.out.println("The method mul begins with [" + i + "," + j + "]");int result = i * j;System.out.println("The method mul ends with " + result);return result;}@Overridepublic int div(int i, int j) {System.out.println("The method div begins with [" + i + "," + j + "]");int result = i / j;System.out.println("The method div ends with " + result);return result;}}

4）ArithmeticCalculatorLoggingProxy.java

package com.atguigu.spring.aop;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;import java.util.Arrays;public class ArithmeticCalculatorLoggingProxy {//要代理的对象private ArithmeticCalculator target;public ArithmeticCalculatorLoggingProxy(ArithmeticCalculator target) {super();this.target = target;}//返回代理对象public ArithmeticCalculator getLoggingProxy(){ArithmeticCalculator proxy = null;ClassLoader loader = target.getClass().getClassLoader();Class [] interfaces = new Class[]{ArithmeticCalculator.class};InvocationHandler h = new InvocationHandler() {/** * proxy: 代理对象。 一般不使用该对象 * method: 正在被调用的方法 * args: 调用方法传入的参数 */@Overridepublic Object invoke(Object proxy, Method method, Object[] args)throws Throwable {String methodName = method.getName();//打印日志System.out.println("[before] The method " + methodName + " begins with " + Arrays.asList(args));//调用目标方法Object result = null;try {//前置通知result = method.invoke(target, args);//返回通知, 可以访问到方法的返回值} catch (NullPointerException e) {e.printStackTrace();//异常通知, 可以访问到方法出现的异常}//后置通知. 因为方法可以能会出异常, 所以访问不到方法的返回值//打印日志System.out.println("[after] The method ends with " + result);return result;}};/** * loader: 代理对象使用的类加载器。  * interfaces: 指定代理对象的类型. 即代理代理对象中可以有哪些方法.  * h: 当具体调用代理对象的方法时, 应该如何进行响应, 实际上就是调用 InvocationHandler 的 invoke 方法 */proxy = (ArithmeticCalculator) Proxy.newProxyInstance(loader, interfaces, h);return proxy;}}

5）LoggingAspect.java

package com.atguigu.spring.aop;import java.util.Arrays;import org.aspectj.lang.JoinPoint;import org.aspectj.lang.annotation.After;import org.aspectj.lang.annotation.Aspect;import org.aspectj.lang.annotation.Before;import org.springframework.stereotype.Component;/** * AOP 的 helloWorld * 1. 加入 jar 包 * com.springsource.net.sf.cglib-2.2.0.jar * com.springsource.org.aopalliance-1.0.0.jar * com.springsource.org.aspectj.weaver-1.6.8.RELEASE.jar * spring-aspects-4.0.0.RELEASE.jar *  * 2. 在 Spring 的配置文件中加入 aop 的命名空间。  *  * 3. 基于注解的方式来使用 AOP * 3.1 在配置文件中配置自动扫描的包: <context:component-scan base-package="com.atguigu.spring.aop"></context:component-scan> * 3.2 加入使 AspjectJ 注解起作用的配置: <aop:aspectj-autoproxy></aop:aspectj-autoproxy> * 为匹配的类自动生成动态代理对象.  *  * 4. 编写切面类:  * 4.1 一个一般的 Java 类 * 4.2 在其中添加要额外实现的功能.  * * 5. 配置切面 * 5.1 切面必须是 IOC 中的 bean: 实际添加了 @Component 注解 * 5.2 声明是一个切面: 添加 @Aspect * 5.3 声明通知: 即额外加入功能对应的方法.  * 5.3.1 前置通知: @Before("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(int, int))") * @Before 表示在目标方法执行之前执行 @Before 标记的方法的方法体.  * @Before 里面的是切入点表达式:  *  * 6. 在通知中访问连接细节: 可以在通知方法中添加 JoinPoint 类型的参数, 从中可以访问到方法的签名和方法的参数.  *  * 7. @After 表示后置通知: 在方法执行之后执行的代码.  *///通过添加 @Aspect 注解声明一个 bean 是一个切面!@Aspect@Componentpublic class LoggingAspect {@Before("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(int, int))")public void beforeMethod(JoinPoint joinPoint){String methodName = joinPoint.getSignature().getName();Object [] args = joinPoint.getArgs();System.out.println("The method " + methodName + " begins with " + Arrays.asList(args));}@After("execution(* com.atguigu.spring.aop.*.*(..))")public void afterMethod(JoinPoint joinPoint){String methodName = joinPoint.getSignature().getName();System.out.println("The method " + methodName + " ends");}}

6）Main.java

package com.atguigu.spring.aop;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class Main {public static void main(String[] args) {//ArithmeticCalculator arithmeticCalculator = new ArithmeticCalculatorImpl();////arithmeticCalculator = //new ArithmeticCalculatorLoggingProxy(arithmeticCalculator).getLoggingProxy();////int result = arithmeticCalculator.add(11, 12);//System.out.println("result:" + result);////result = arithmeticCalculator.div(21, 3);//System.out.println("result:" + result);ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext-aop.xml");ArithmeticCalculator arithmeticCalculator = (ArithmeticCalculator) ctx.getBean("arithmeticCalculator");System.out.println(arithmeticCalculator.getClass().getName());int result = arithmeticCalculator.add(11, 12);System.out.println("result:" + result);result = arithmeticCalculator.div(21, 3);System.out.println("result:" + result);}}

2、com.atguigu.spring.helloworld包

1）HelloWorld.java

package com.atguigu.spring.helloworld;public class HelloWorld {//字段private String user;public HelloWorld() {System.out.println("HelloWorld's constructor...");}//JavaBean 使用 setter 和 getter 来定义属性public void setUserName(String user) {System.out.println("setUserName:" + user);this.user = user;}public void hello(){System.out.println("Hello:" + user);}public void init(){System.out.println("init method...");}public void destroy(){System.out.println("destroy method...");}}

2）Main.java

package com.atguigu.spring.helloworld;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class Main {public static void main(String[] args) {//1. 创建 IOC 容器ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");//2. 从 IOC 容器中获取 bean 实例HelloWorld helloWorld = (HelloWorld) ctx.getBean("helloWorld");//3. 调用 bean 的方法helloWorld.hello();HelloWorld helloWorld2 = (HelloWorld) ctx.getBean("helloWorld");System.out.println(helloWorld == helloWorld2);//4. 关闭容器ctx.close();}}

3、com.atguigu.spring.ref包

1）Main.java

package com.atguigu.spring.ref;import org.springframework.context.support.ClassPathXmlApplicationContext;public class Main {public static void main(String[] args) {//1. 创建 IOC 容器ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext-annotation.xml");UserAction userAction = (UserAction) ctx.getBean("userAction");userAction.execute();}}

2）UserAction.java

package com.atguigu.spring.ref;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;@Controllerpublic class UserAction {private UserService userService;@Autowiredpublic void setUserService(UserService userService) {this.userService = userService;}public void execute(){System.out.println("execute...");userService.addNew();}}

3）UserDao.java

package com.atguigu.spring.ref;import org.springframework.stereotype.Repository;@Repositorypublic class UserDao {public void save(){System.out.println("UserDao's save...");}}

4）UserService.java

package com.atguigu.spring.ref;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;@Servicepublic class UserService {@Autowiredprivate UserDao userDao;public void setUserDao(UserDao userDao) {this.userDao = userDao;}public void addNew(){System.out.println("addNew...");userDao.save();}}