springboot中使用aop技术

aop是面向切面编程的意思，它可以需要先选择一些切入点，然后对这些切入点进行拦截，注入统一的代码逻辑，这也是解耦的一种方式，也是为了避免重复的代码，让开发人员把关注点放在业务上。

引用包

'org.springframework.boot:spring-boot-starter-aop'

添加切入点

/**
 * 基于com.lind.basic.controller包下的方法进行拦截.
 */
@Aspect
@Component
public class AopPrintConstController {
  private static final Logger logger = LoggerFactory.getLogger(AopPrintConstController.class);

  /**
   * 横切点，哪些方法需要被横切.
   */
  @Pointcut(value = "execution(public * com.lind.basic.controller..*.*(..))")
  public void cutOffPoint() {
  }

  /**
   * @param joinPoint 具体的方法之前执行.
   */
  @Before("cutOffPoint()")
  public void doBefore(JoinPoint joinPoint) throws Throwable {
    logger.info("cutOffPoint.before...");
    ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
    HttpServletRequest request = requestAttributes.getRequest();
    String requestURI = request.getRequestURI();
    String remoteAddr = request.getRemoteAddr();   //这个方法取客户端ip"不够好"
    String requestMethod = request.getMethod();
    String declaringTypeName = joinPoint.getSignature().getDeclaringTypeName();
    String methodName = joinPoint.getSignature().getName();
    Object[] args = joinPoint.getArgs();
    logger.info("请求url=" + requestURI + ",客户端ip=" + remoteAddr + ",请求方式=" + requestMethod + ",请求的类名=" + declaringTypeName + ",方法名=" + methodName + ",入参=" + args);

  }

  /**
   * 解用于获取方法的返回值.
   *
   * @param obj 返回值
   */
  @AfterReturning(returning = "obj", pointcut = "cutOffPoint()")
  public void doBefore(Object obj) throws Throwable {
    logger.info("RESPONSE : " + obj);
  }


}

测试

当我们访问controller下的接口下，在控制台中将输出方法执行前和执行后的结果

com.lind.basic.AopPrintConstController   : 请求url=/hello/1,客户端ip=0:0:0:0:0:0:0:1,请求方式=GET,请求的类名=...
com.lind.basic.controller.H com.lind.basic.AopPrintConstController   : RESPONSE : <200 OK,com.lind.basic.entity.Token@249f92d9,{}>