Spring面向切面编程AOP详情

@Configuration
@EnableAspectJAutoProxy
public class AppConfig {
 
}

@Aspect //告诉Spring 这是一个切面
@Component  //交给Spring容器管理
public class MyAspect {
 
}

@RestController
@RequestMapping("/my")
public class MyController {
 
    @GetMapping("/test")
    public void test() {
        System.out.println("test 方法");
    }
}

  //表达式
  @Pointcut("execution (public * com.yc.springboot.controller.MyController.test())")
  public void controller(){}; //签名

execution(modifiers-pattern? ret-type-pattern declaring-type-pattern?name-pattern(param-pattern) throws-pattern?)
execution(方法修饰符(可选) 返回类型 类路径 方法名 参数 异常模式（可选）)

 
@Aspect //告诉Spring 这是一个切面
@Component  //告诉Spring容器需要管理该对象
public class MyAspect {
 
    //通过规则确定哪些方法是需要增强的
    @Pointcut("execution (public * com.yc.springboot.controller.MyController.*(..))")
    public void controller() {
    }
 
    //前置增强
    @Before("controller()")
    public void before(JoinPoint joinPoint) {
        System.out.println("before advice");
    }
 
    //返回增强
    @AfterReturning(
            pointcut = "controller()",
            returning = "retVal"
    )
    public void afterReturning(Object retVal) {
        System.out.println("after returning advice, 返回结果 retVal:"   retVal);
    }
 
    //异常增强
    @AfterThrowing(
            pointcut = "controller()",
            throwing = "ex"
    )
    public void afterThrowing(Exception ex) {
        System.out.println("after throwing advice, 异常 ex:"   ex.getMessage());
    }
 
    //后置增强
    @After("controller()")
    public void after(JoinPoint joinPoint) {
        System.out.println("after advice");
    }
 
    //环绕增强
    @Around("controller()")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
        System.out.println("before advice");
        //相当于是before advice
        Object reVal = null;
        try {
            reVal = joinPoint.proceed();
        } catch (Exception e) {
            //相当于afterthrowing advice
            System.out.println("afterthrowing advice");
        }
        //相当于是after advice
        System.out.println("after advice");
        return reVal;
    }
}

@RestController
@RequestMapping("/my")
public class MyController {
 
    @GetMapping("/testBefore")
    public void testBefore() {
        System.out.println("testBefore 业务方法");
    }
 
    @GetMapping("/testAfterReturning")
    public String testAfterReturning() {
        System.out.println("testAfterReturning 业务方法");
        return "我是一个返回值";
    }
 
    @GetMapping("/testAfterThrowing")
    public void testAfterThrowing() {
        System.out.println("testAfterThrowing 业务方法");
        int a = 0;
        int b = 1 / a;
    }
 
    @GetMapping("/testAfter")
    public void testAfter() {
        System.out.println("testAfter 业务方法");
    }
 
    @GetMapping("/around")
    public void around() {
        System.out.println("around 业务方法");
    }
}

/**
 * 日志的切面
 */
@Aspect
@Component
public class LogAspect {
 
    @Resource
    private IdWorker idWorker;
 
    @Pointcut("execution (public * com.yc.core.controller.*.*(..))")
    public void log(){}
 
    /**
     * 使用环绕增强实现日志打印
     * @param joinPoint
     * @return
     * @throws Throwable
     */
    @Around("log()")
    public Object logAround(ProceedingJoinPoint joinPoint) throws Throwable {
        //获得执行方法的类和名称
        String className = joinPoint.getTarget().getClass().getName();
        //获得方法名
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        String methodName = signature.getMethod().getName();
        //获得参数
        Object[] args = joinPoint.getArgs();
        long requestId = idWorker.nextId();
        //打印参数
        LogHelper.writeInfoLog(className, methodName, "requestId:"   requestId   ",params:"   JSONObject.toJSONString(args));
        long startTime = System.currentTimeMillis();
        //执行业务方法
        Object result = null;
        try {
            result = joinPoint.proceed();
        } catch (Exception e) {
            LogHelper.writeErrLog(className, methodName, "requestId:"   requestId   ",异常啦："   LogAspect.getStackTrace(e));
        }
        long endTime = System.currentTimeMillis();
        //打印结果
        LogHelper.writeInfoLog(className, methodName, "requestId:"   requestId   ",耗时："   (endTime - startTime)    "ms，result:"   JSONObject.toJSONString(result));
        //返回
        return result;
    }
 
    /**
     * 获取异常的堆栈信息
     * @param throwable
     * @return
     */
    public static String getStackTrace(Throwable throwable)
    {
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        try
        {
            throwable.printStackTrace(pw);
            return sw.toString();
        } finally
        {
            pw.close();
        }
    }
}

/**
 * 自定义日志注解
 */
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Log {
}

    @Pointcut("@annotation(com.yc.core.annotation.Log)")
    public void logAnnotation(){}

    @Log
    @PostMapping(value = "testannotation")
    public AOPTestVO testannotation(@RequestBody AOPTestDTO aopTestDTO) {
        AOPTestVO aopTestVO = new AOPTestVO();
        aopTestVO.setCode(1);
        aopTestVO.setMsg("哈哈哈");
        return aopTestVO;
    }

result = joinPoint.proceed();

public Object proceed(Object[] args) throws Throwable;

@Data
@ApiModel("aop参数基类")
public class AOPBaseDTO {
    @ApiModelProperty(value = "请求id", hidden = true)
    private long requestId;
}

@Data
@ApiModel("aop测试类")
public class AOPTestDTO extends AOPBaseDTO{
 
    @ApiModelProperty(value = "姓名")
    private String name;
 
    @ApiModelProperty(value = "年龄")
    private int age;
}

    /**
     * 使用环绕增强实现日志打印
     * @param joinPoint
     * @return
     * @throws Throwable
     */
    @Around("logAnnotation()")
    public Object logAround(ProceedingJoinPoint joinPoint) throws Throwable {
        //获得执行方法的类和名称
        String className = joinPoint.getTarget().getClass().getName();
        //获得方法名
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        String methodName = signature.getMethod().getName();
        //获得参数
        Object[] args = joinPoint.getArgs();
        long requestId = idWorker.nextId();
        for(int i = 0; i < args.length; i  ) {
            if (args[i] instanceof AOPBaseDTO) {
                //增加requestId
                ((AOPBaseDTO) args[i]).setRequestId(requestId);
            }
        }
        //打印参数
        LogHelper.writeInfoLog(className, methodName, "requestId:"   requestId   ",params:"   JSONObject.toJSONString(args));
        long startTime = System.currentTimeMillis();
        //执行业务方法
        Object result = null;
        try {
            result = joinPoint.proceed(args);
        } catch (Exception e) {
            LogHelper.writeErrLog(className, methodName, "requestId:"   requestId   ",异常啦："   LogAspect.getStackTrace(e));
        }
        long endTime = System.currentTimeMillis();
        //打印结果
        LogHelper.writeInfoLog(className, methodName, "requestId:"   requestId   ",耗时："   (endTime - startTime)    "ms，result:"   JSONObject.toJSONString(result));
        //返回
        return result;
    }