Spring aop 面向切面编程

1、作用

不修改原有代码逻辑，通过切点的方式，提高代码可读性

2、术语

Aspect: 切面: 切面类，封装切面类执行逻辑

JoinPoint: 连接点: 被AOP连接的目标类的方法；可以插入切面的点

Advice: 通知: 在连接点具体动作，Before，Around

Pointcut: 切点: 执行到哪些目标方法上

3、通知分类

Before 前置通知 方法执行前；Around环绕通知，自定义前后行为；

4、通过Spring AOP实现日志审计

自定义注解实现切点

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface  Auditable {
    String value() default "";
}

日志类

@Data
@AllArgsConstructor
public class Syslog {
    private String methodName;
    private String message;
    private String args;
    private String result;
    private String status;
    private String exception;
}

切面类

/**
 * 切面类
 *
 */
@Component
@Aspect
public class AuditAspect {
    private static final Logger logger = LoggerFactory.getLogger(AuditAspect.class);
    @Around("@annotation(auditable)")
    public Object audit(ProceedingJoinPoint joinPoint, Auditable auditable) throws Throwable {
        String methodName = joinPoint.getSignature().getName();
        String message = auditable.value();
        // 获取参数
        Object[] args = joinPoint.getArgs();
        String arrsString = args != null ? Arrays.stream(args).map(Object::toString).collect(Collectors.joining(",")) : null;
        Syslog syslog = new Syslog(methodName, message, arrsString, null, null, null);
        try {
            Object proceed = joinPoint.proceed();
            syslog.setResult(proceed == null ? "null" : proceed.toString());
            syslog.setStatus("成功");
            return proceed;
        } catch (Throwable e) {
            syslog.setStatus("失败");
            syslog.setException(e.getMessage());
            throw e;
        } finally {
            logger.info("日志审计记录: {}", syslog);
        }
    }
}

5、灵境给的使用示例

@Aspect
@Component
public class LoggingAspect {

    // 定义切点：service 包下所有方法
    @Pointcut("execution(* com.example.service.*.*(..))")
    public void serviceMethod() {}

    @Before("serviceMethod()")
    public void logBefore(JoinPoint joinPoint) {
        System.out.println("调用方法：" + joinPoint.getSignature().getName());
    }

    @Around("serviceMethod()")
    public Object measureTime(ProceedingJoinPoint pjp) throws Throwable {
        long start = System.currentTimeMillis();
        Object result = pjp.proceed();
        long time = System.currentTimeMillis() - start;
        System.out.println(pjp.getSignature() + " 耗时 " + time + "ms");
        return result;
    }
}