业务层框架spring(AOP)

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);
	
}

package com.atguigu.spring.aop;

import org.springframework.stereotype.Component;

public class ArithmeticCalculatorImpl implements ArithmeticCalculator {

	@Override
	public int add(int i, int j) {
		int result = i + j;
		return result;
	}

	@Override
	public int sub(int i, int j) {
		int result = i - j;
		return result;
	}

	@Override
	public int mul(int i, int j) {
		int result = i * j;
		return result;
	}

	@Override
	public int div(int i, int j) {
		int result = i / j;
		return result;
	}

}

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;
		//获取类加载器,代理对象由哪一个类加载器负责加载
		ClassLoader loader = target.getClass().getClassLoader();
        //理对象的类型，即其中有哪些方法
		Class [] interfaces = new Class[]{ArithmeticCalculator.class};
        //当调用代理对象中的方法时，该执行带的代码
		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
			 */
			@Override
			public 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;
			}
		};
		
		/**创建实现类的一个动态代理
		 * 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;
	}
}

package com.qinfen.entity;

public class Test {
	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);
	}
}

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
@Component
public class LoggingAspect {

	@Before("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(int, int))")
	public void beforeMethod(JoinPoint joinPoint){
        //获取方法名
		String methodName = joinPoint.getSignature().getName();
        //获取方法参数
		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");
	}
	
}

/**
* 在方法执行之后执行的代码. 无论该方法是否出现异常
*/
@After("declareJointPointExpression()")
public void afterMethod(JoinPoint joinPoint){
    String methodName = joinPoint.getSignature().getName();
    System.out.println("The method " + methodName + " ends");
}

	/**
	 * 在方法法正常结束受执行的代码
	 * 返回通知是可以访问到方法的返回值的!
	 */
	@AfterReturning(value="declareJointPointExpression()",
			returning="result")
	public void afterReturning(JoinPoint joinPoint, Object result){
		String methodName = joinPoint.getSignature().getName();
		System.out.println("The method " + methodName + " ends with " + result);
	}

/**
* 在目标方法出现异常时会执行的代码.
* 可以访问到异常对象; 且可以指定在出现特定异常时在执行通知代码
*/
@AfterThrowing(value="declareJointPointExpression()",
throwing="e")
public void afterThrowing(JoinPoint joinPoint, Exception e){
    String methodName = joinPoint.getSignature().getName();
    System.out.println("The method " + methodName + " occurs excetion:" + e);
}

	/**
	 * 环绕通知需要携带 ProceedingJoinPoint 类型的参数. 
	 * 环绕通知类似于动态代理的全过程: ProceedingJoinPoint 类型的参数可以决定是否执行目标方法.
	 * 且环绕通知必须有返回值, 返回值即为目标方法的返回值
	 */
	@Around("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(..))")
	public Object aroundMethod(ProceedingJoinPoint pjd){
		
		Object result = null;
		String methodName = pjd.getSignature().getName();
		
		try {
			//前置通知
			System.out.println("The method " + methodName + " begins with " + Arrays.asList(pjd.getArgs()));
			//执行目标方法
			result = pjd.proceed();
			//返回通知
			System.out.println("The method " + methodName + " ends with " + result);
		} catch (Throwable e) {
			//异常通知
			System.out.println("The method " + methodName + " occurs exception:" + e);
			throw new RuntimeException(e);
		}
		//后置通知
		System.out.println("The method " + methodName + " ends");
		
		return result;
	}
	

**
 * 可以使用 @Order 注解指定切面的优先级, 值越小优先级越高
 */
@Order(2)
@Aspect
@Component
public class LoggingAspect {
}

/**
 * 可以使用 @Order 注解指定切面的优先级, 值越小优先级越高
 */
@Order(2)
@Aspect
@Component
public class LoggingAspect {
	
	/**
	 * 定义一个方法, 用于声明切入点表达式. 一般地, 该方法中再不需要添入其他的代码. 
	 * 使用 @Pointcut 来声明切入点表达式. 
	 * 后面的其他通知直接使用方法名来引用当前的切入点表达式. 
	 */
	@Pointcut("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(..))")
	public void declareJointPointExpression(){}
	
	/**
	 * 在 com.atguigu.spring.aop.ArithmeticCalculator 接口的每一个实现类的每一个方法开始之前执行一段代码
	 */
	@Before("declareJointPointExpression()")
	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));
	}
}

@Order(1)
@Aspect
@Component
public class VlidationAspect {

	@Before("com.atguigu.spring.aop.LoggingAspect.declareJointPointExpression()")
	public void validateArgs(JoinPoint joinPoint){
		System.out.println("-->validate:" + Arrays.asList(joinPoint.getArgs()));
	}
	
}

package com.atguigu.spring.aop.xml;

import java.util.Arrays;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;

public class LoggingAspect {
	
	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));
	}
	
	public void afterMethod(JoinPoint joinPoint){
		String methodName = joinPoint.getSignature().getName();
		System.out.println("The method " + methodName + " ends");
	}
	
	public void afterReturning(JoinPoint joinPoint, Object result){
		String methodName = joinPoint.getSignature().getName();
		System.out.println("The method " + methodName + " ends with " + result);
	}
	
	public void afterThrowing(JoinPoint joinPoint, Exception e){
		String methodName = joinPoint.getSignature().getName();
		System.out.println("The method " + methodName + " occurs excetion:" + e);
	}
	
	@Around("execution(public int com.atguigu.spring.aop.ArithmeticCalculator.*(..))")
	public Object aroundMethod(ProceedingJoinPoint pjd){
		
		Object result = null;
		String methodName = pjd.getSignature().getName();
		
		try {
			//前置通知
			System.out.println("The method " + methodName + " begins with " + Arrays.asList(pjd.getArgs()));
			//执行目标方法
			result = pjd.proceed();
			//返回通知
			System.out.println("The method " + methodName + " ends with " + result);
		} catch (Throwable e) {
			//异常通知
			System.out.println("The method " + methodName + " occurs exception:" + e);
			throw new RuntimeException(e);
		}
		//后置通知
		System.out.println("The method " + methodName + " ends");
		
		return result;
	}
}

package com.atguigu.spring.aop.xml;

import java.util.Arrays;

import org.aspectj.lang.JoinPoint;

public class VlidationAspect {

	public void validateArgs(JoinPoint joinPoint){
		System.out.println("-->validate:" + Arrays.asList(joinPoint.getArgs()));
	}
	
}

package com.atguigu.spring.aop.xml;

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

public class Main {
	
	public static void main(String[] args) {
		
		ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext-xml.xml");
		ArithmeticCalculator arithmeticCalculator = (ArithmeticCalculator) ctx.getBean("arithmeticCalculator");
		
		System.out.println(arithmeticCalculator.getClass().getName());
		
		int result = arithmeticCalculator.add(1, 2);
		System.out.println("result:" + result);
		
		result = arithmeticCalculator.div(1000, 0);
		System.out.println("result:" + result);
	}
	
}