AOP和动态代理-自定义注解切入使用-01

Posted 2022-06-07 JF Coder

JDK动态代理与SpringAop

动态代理

1. JDK 动态代理 使用JAVA反射包中的类和接口实现动态代理的功能，JAVA.lang.reflect包；主要是三个类：

InvocationHandler,Method,Proxy;

2. CGLIB动态代理，第三方工具类库，创建代理对象，cglib的原理是继承，通过继承目标类，创建它的子类，在子类中重写父类中同名的方法，实现功能的修改

   注意：cglib是继承，重写方法，所以要求目标类不能是final修饰的，方法也不能是final的，cglib的要求目标类比较宽松，只要继承就可以了，cglib在很多的框架中使用，比如mybatis，spring框架中都有使用

JDK动态代理

1. Method类表示方法，目标类的方法；通过Method可以执行某个目标类的方法 Method.invoke();

2. InvocationHandler接口（调用处理器） 就一个方法Invoke方法

public Object invoke(Object proxy, Method method, Object[] args)
 throws Throwable;

3. Proxy类：核心的对象 创建代理对象

   @param ClassLoader 目标类加载器 getClass().getClassLo ader()

   @param interfaces 接口 目标类实现的接口 也是反射获取的

   @param InvocationHandler 代理类要完成的功能 我们自己写的

   @return 目标对象的代理对象

public static Object newProxyInstance(ClassLoader loader,
                                   Class<?>[] interfaces,
                                   InvocationHandler h)

AOP

Demo 日志简单切面

package com.example.demo.aspect;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.demo.annotation.Log;
import com.example.demo.entity.Logs;
import com.example.demo.enums.BusinessStatus;
import com.example.demo.service.LogsService;
import com.example.demo.utils.IpUtils;
import com.example.demo.utils.RedisService;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import javax.servlet.http.HttpServletRequest;
import java.util.concurrent.TimeUnit;

/**
 * @author JFCODER
 * @date 2022/5/29
 * @description 日志类
 */

@Component
@Aspect
public class DBLogsAop 

    @Autowired
    private LogsService logsService;
    @Autowired
    private HttpServletRequest request;
    @Autowired
    private RedisService redisService;

    private static final Logger loginfo = LoggerFactory.getLogger(DBLogsAop.class);

    @Before("@annotation(log)")
    public void beforeRuning(JoinPoint joinPoint, Log log) throws Throwable 
        loginfo.info("==========前置通知=============");
        if (redisReduce(request)) 
            loginfo.warn("==========请求成功=============");
         else 
            loginfo.error("频繁请求");
            throw new Throwable();
        
    

    private boolean redisReduce(HttpServletRequest request) 
        String ip = IpUtils.getIpAddr(request);
        String id = request.getSession().getId();
        String key = "AOP:KEY" + ip.concat(id);

        if (redisService.hasKey(key)) 
            return false;
         else 
            redisService.setCacheObject(key, ip, 10L, TimeUnit.SECONDS);
            return true;
        
    


    @AfterReturning(pointcut = "@annotation(log)", returning = "result")
    public void doAfterReturning(JoinPoint joinPoint, Log log, Object result) 
        handleLog(joinPoint, log, null, result);
    

    /**
     * 拦截异常操作
     *
     * @param joinPoint 切点
     * @param e         异常
     */
    @AfterThrowing(value = "@annotation(log)", throwing = "e")
    public void doAfterThrowing(JoinPoint joinPoint, Log log, Exception e) 
        handleLog(joinPoint, log, e, null);
    

    protected void handleLog(final JoinPoint joinPoint, Log log, final Exception e, Object result) 
        /*日志信息收集*/
        Logs logs = new Logs();
        try 

            String ip = IpUtils.getIpAddr(request);
            logs.setIp(ip);
            logs.setUrl(request.getRequestURI());
            logs.setCode(BusinessStatus.SUCCESS.toString());
            if (e != null) 
                logs.setCode(BusinessStatus.FAIL.toString());
            
            Object[] args = joinPoint.getArgs();
            if (args.length > 0) 
//                SourceLocation sourceLocation = joinPoint.getSourceLocation();
//                if (sourceLocation != null) 
//                    System.out.println(sourceLocation.getWithinType());
//                    System.out.println(sourceLocation.getFileName());
//                
                System.out.println(joinPoint.getSignature());
                System.out.println(joinPoint.getTarget());
                StringBuilder buffer = new StringBuilder();
                for (Object arg : args) 
                    buffer.append(arg);
                
                logs.setContent(buffer.toString());
            

         catch (Exception exception) 
            logs.setCode(BusinessStatus.FAIL.toString());
            exception.printStackTrace();
         finally 
            logsService.saveLogs(logs);
        
    

package com.example.demo.annotation;

import com.example.demo.enums.BusinessStatus;
import com.example.demo.enums.BusinessType;
import com.example.demo.enums.OperatorType;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * @author JFCODER
 * @date 2022/5/29
 * @description 请求日志注解
 */
@Target(ElementType.TYPE,ElementType.METHOD,ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface Log 
    /**
     * 请求url
     * */
    public String url() default "";

    /**
     * 功能
     * */
    public BusinessType businessType() default BusinessType.OTHER;


    /**
     * 操作人类别
     */
    public OperatorType operatorType() default OperatorType.MANAGE;

    /**
     * 操作状态
     */
    public BusinessStatus businessStatus() default BusinessStatus.FAIL;

DEMO 动态代理跟AOP的使用

package com.example.demo.aspect;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.aop.support.AopUtils;
import org.springframework.stereotype.Component;

import java.lang.reflect.Method;

/**
 * @author JFCODER
 * @date 2022/5/29
 * @description 自定义切换mapper执行方法
 */
@Component
@Aspect
public class MybatisAop 

    private static final Logger loginfo = LoggerFactory.getLogger(MybatisAop.class);


    /**
     * 定义AOP签名 (切入所有使用的方法)
     */
    public static final String POINTCUT_SIGN = "execution(* com.example.demo.mapper..*.*(..)) || " +
            "execution(* com.baomidou.mybatisplus.core.mapper..*.*(..))";

    /**
     * 声明AOP签名
     */
    @Pointcut(POINTCUT_SIGN)
    public void pointcut() 
    


    @Around("pointcut()")
    public Object switchMethod(ProceedingJoinPoint point) throws Throwable 

        System.out.println("我是环绕通知前....");
        //执行目标函数
        MethodSignature signature =(MethodSignature) point.getSignature();
        Class<?>[] parameterTypes = signature.getMethod().getParameterTypes();
        /*如果是getAllA方法 则调用getAllB*/
        if (signature.getMethod().getName().contains("getAllA")) 
            Method method = point.getTarget().getClass().getMethod("getAllB", parameterTypes);
            return AopUtils.invokeJoinpointUsingReflection(point.getTarget(), method, point.getArgs());
        
        System.out.println("我是环绕通知后....");

        return point.proceed();
    

关于Spring提供的动态代理反射和AOP工具类

ReflectUtils

	// used by MethodInterceptorGenerated generated code
	public static Method[] findMethods(String[] namesAndDescriptors, Method[] methods) 
		Map map = new HashMap();
		for (int i = 0; i < methods.length; i++) 
			Method method = methods[i];
			map.put(method.getName() + Type.getMethodDescriptor(method), method);
		
		Method[] result = new Method[namesAndDescriptors.length / 2];
		for (int i = 0; i < result.length; i++) 
			result[i] = (Method) map.get(namesAndDescriptors[i * 2] + namesAndDescriptors[i * 2 + 1]);
			if (result[i] == null) 
				// TODO: error?
			
		
		return result;
	

AopUtils

AOP支持代码的实用方法。 主要用于Spring的AOP支持中的内部使用

	/**
   作为AOP方法调用的一部分，通过反射调用给定的目标。
    参数: target–目标对象 method–要调用的方法     
    args–方法的参数 返回值: 调用结果（如果有） 
    抛出: Throwable–如果由目标方法抛出 AOPINotationException–
    在反射错误的情况下 reflection error
	 */
	@Nullable
	public static Object invokeJoinpointUsingReflection(@Nullable Object target, Method method, Object[] args)
			throws Throwable 

		// Use reflection to invoke the method.
		try 
			ReflectionUtils.makeAccessible(method);
			return method.invoke(target, args);
		
		catch (InvocationTargetException ex) 
			// Invoked method threw a checked exception.
			// We must rethrow it. The client won't see the interceptor.
			throw ex.getTargetException();
		
		catch (IllegalArgumentException ex) 
			throw new AopInvocationException("AOP configuration seems to be invalid: tried calling method [" +
					method + "] on target [" + target + "]", ex);
		
		catch (IllegalAccessException ex) 
			throw new AopInvocationException("Could not access method [" + method + "]", ex);
		
	

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