Spring—aop使用整理

Posted 2021-06-12 zqq_hello_world

文章目录

• SpringAop使用
• • 前置通知
  • 环绕通知
  • 后置通知
  • 返回后通知
  • 异常通知
  • Aop切自定义注解
  • Spring-Web项目中获取Request\\Response
  • 代码地址

SpringAop使用

前置通知

/**
 * 前置通知 , 进入方法前进入切面
 * @param joinPoint
 */
//@Before("execution(* com.example.demo.service.impl.TestServiceImpl.*(..))")
@Before("execution(* com.example.demo.service.impl.TestServiceImpl.printTest(String))")
public void beforeAdvise(JoinPoint joinPoint){
    //获取request ，在request获取参数（http请求传的参数）
    HttpServletRequest request = ServletUtil.getRequest();
    Map<String,String[]> map = request.getParameterMap();
    for(Map.Entry<String,String[]> entry:map.entrySet()){
        String name = entry.getKey();
        String[] strs = entry.getValue();
        Arrays.stream(strs).forEach(s -> {
            System.out.println("参数：" + name + "=" + s);
        });
    }
    //切面方法的参数
    Object[] objects = joinPoint.getArgs();
    Arrays.stream(objects).forEach(o -> {
        if(o instanceof String){
            System.out.println("string类型参数：" + o);
        }
    });
    System.out.println("前置通知===线程：" + Thread.currentThread().getName());
}

环绕通知

/**
 * 环绕通知，前后进入切面，通过代理，可阻断方法执行和返回
 * @param joinPoint
 */
@Around("execution(* com.example.demo.service.impl.TestServiceImpl.printTest(String))")
public String around(ProceedingJoinPoint joinPoint) throws Throwable {
    System.out.println("环绕通知-start：" +Thread.currentThread().getName());
    String result = (String) joinPoint.proceed();
    System.out.println("环绕通知-end：" +Thread.currentThread().getName());
    return result;
}

后置通知

/**
 * 后置通知,在目标方法执行后执行，不能获取方法的执行结果
 */
@After("execution(* com.example.demo.service.impl.TestServiceImpl.printTest(String))")
public void after(JoinPoint joinPoint){
    String name = joinPoint.getSignature().getName();
    System.out.println("后置通知-start：" +Thread.currentThread().getName() + "; " + name);
}

返回后通知

/**
 * 返回后通知，用returning获取返回值
 * @param point
 * @param result 等于returning的值
 */
@AfterReturning(value = "execution(* com.example.demo.service.impl.TestServiceImpl.printTest(String))",returning = "result")
public void afterReturning(JoinPoint point,String result){
    System.out.println("返回后通知-start：" +Thread.currentThread().getName() + "; " + result);
}

异常通知

/**
 * 异常通知
 * @param ex 等于throwing
 */
  @AfterThrowing(value = "execution(* com.example.demo.service.impl.TestServiceImpl.printTest(String))",throwing = "ex")
public void afterThrowing(Throwable ex){
    System.out.println("异常通知：" + Thread.currentThread().getName());
    ex.printStackTrace();
}

Aop切自定义注解

1. 自定义注解

   /**
    * 自定义注解，切面切点切这个注解
    * @author zqq
    * @date 2021/5/10 11:33
    */
   @Documented
   @Target({ElementType.METHOD})
   @Retention(RetentionPolicy.RUNTIME)
   public @interface LogAnnotation {
   
       String value() default "";
   }
   

2. 定义切面类

   /**
    * aop切面切自定义注解
    * @author zqq
    * @date 2021/5/10 11:44
    */
   @Aspect //切面
   @Component  //spring扫描，注册成spring的bean
   public class LogAspect {
   
       /**
        * 切注解，实现简单日志记录
        * @param joinPoint
        */
       @Before(value = "@annotation(com.example.demo.annotation.LogAnnotation)")
       public void before(JoinPoint joinPoint){
           try {
               HttpServletRequest request = ServletUtil.getRequest();
               Map<String, String[]> map = request.getParameterMap();
               //打印普通参数
               for(Map.Entry<String,String[]> entry : map.entrySet()){
                   String name = entry.getKey();
                   for(String val : entry.getValue()){
                       System.out.println("请求参数：" + name + "=" + val);
                   }
               }
               //获取注解
               LogAnnotation annotation = getDeclaredAnnotation(joinPoint);
               System.out.println("annotation.value = "+ annotation.value());
           } catch (Exception e) {
               e.printStackTrace();
           }
       }
   
       /**
        * 获取方法上固定的注解
        * @param joinPoint
        * @return
        * @throws NoSuchMethodException
        */
       private LogAnnotation getDeclaredAnnotation(JoinPoint joinPoint) throws NoSuchMethodException {
           String methodName = joinPoint.getSignature().getName();//获取方法名称
           Class<?> targetClass = joinPoint.getTarget().getClass();//获取类类型
           Class<?>[] parameterTypes = ((MethodSignature) joinPoint.getSignature()).getParameterTypes();//获取参数
           Method objMethod = targetClass.getMethod(methodName, parameterTypes);//获取方法
           return objMethod.getDeclaredAnnotation(LogAnnotation.class);//返回方法的ReportLog注解
       }
   }
   

Spring-Web项目中获取Request\\Response

/**
 *  在spring web RequestAttributes获取request/response，本质是存放在ThreadLocal（线程副本）中，然后取出
 * @author zqq
 * @date 2021/5/10 13:34
 */
public class ServletUtil {

    /**
     * 获取Request
     * @return
     */
    public static HttpServletRequest getRequest(){
        return getServletRequestAttributes().getRequest();
    }

    /**
     * 获取Response
     * @return
     */
    public static HttpServletResponse getResponse(){
        return getServletRequestAttributes().getResponse();
    }

    /**
     * 公共代码部分获取ServletRequestAttributes
     * @return
     */
    private static ServletRequestAttributes getServletRequestAttributes(){
        RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
        return (ServletRequestAttributes) requestAttributes;
    }
}

代码地址

Gitee：https://gitee.com/zhaoqingquan/springaop