java 自定义注解实现后端防重复提交操作

ゝ一纸荒年。 2022-12-22 00:47 182阅读 0赞

**实现思路：当进入到页面生成token。进行表单提交后。校验token。第一次提交成功消除token信息。多次提交发现token不存在。校验不通过**

**用的如下类：**

GenerateToken注解标识在方法上。自动生成token。返回到页面。由下一次表单提交验证

ValidateToken注解标识在方法上。用来验证提交来的信息是否有token信息。以及验证重复提交

AopRejectMultSubmitConfig类基于aop代理。进行切入点切入。GenerateToken注解再方法进入之前进行生成token。ValidateToken注解进行的是环绕同通知。验证token.如果通过。调用方法

![20201117101236712.png][]

代码如下：

**GenerateToken注解**

==================**GenerateToken**=======================

@Documented
    @Target(ElementType.METHOD)
    @Retention(RetentionPolicy.RUNTIME)
    public @interface GenerateToken {
        String size() default "64";
    }

===================**GenerateToken**======================

ValidateToken注解
    
    ===================ValidateToken======================
    @Target(ElementType.METHOD)
    @Documented
    @Retention(RetentionPolicy.RUNTIME)
    public @interface ValidateToken {
    }

===================**ValidateToken**======================

**AopRejectMultSubmitConfig 类**

/**
     * author:wwz
     */
    @Component
    @Aspect
    public class AopRejectMultSubmitConfig {
    
        private final static Logger logger = LoggerFactory.getLogger(AopRejectMultSubmitConfig.class);
    
        @Autowired
        private RedisTemplate redisTemplate;
        private static final String PROJ_ST_MENU = "proj:menu:";
    
        private static final int MAX_AGE = 600;
    
        private static class LockHolder{
            private static Lock lock = new ReentrantLock(true);
        } ;
    
        /**
         * 生成token
         */
        @Before("@annotation(com.x.modules.gcjsy.basic.annoation.GenerateToken)")
        public void before(){
            HttpServletResponse response =  ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getResponse();
            HttpServletRequest request =  ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
            if(!isHaveToken(request)){
                String uuid = UUID.randomUUID().toString();
                initCookie(response,uuid,MAX_AGE);
                UserSession userSession = PermissionHelper.currentUserSession();
                redisTemplate.opsForValue().set(PROJ_ST_MENU+uuid+":"+request.getRequestURI()+":"+userSession.getUserId(),request.getRequestURI(),MAX_AGE, TimeUnit.SECONDS);
            }
        }
    
        /**
         * 判断是否有token
         * @param request
         * @return
         */
        private boolean isHaveToken(HttpServletRequest request){
            String value = getValue(request);
            if(value == null){
                return false;
            }
            UserSession userSession = PermissionHelper.currentUserSession();
            Object url = redisTemplate.opsForValue().get(PROJ_ST_MENU+value+":"+request.getRequestURI()+":"+userSession.getUserId());
            if(url == null||"".equals(url)||!request.getRequestURI().equals(url)){
                return false;
            };
            return true;
        }
    
        private void initCookie(HttpServletResponse response,String uuid,int maxAge){
            Cookie cookie = new Cookie("tokenUUID",uuid);
            cookie.setPath("/");
            cookie.setMaxAge(maxAge);
            cookie.setHttpOnly(true);
            response.addCookie(cookie);
        }
    
        private String getValue(HttpServletRequest request){
            Cookie[] cookies = request.getCookies();
            for(Cookie cookie:cookies) {
                if ("tokenUUID".equals(cookie.getName())) {
                    return cookie.getValue();
                }
            }
            return null;
        }
        /**
         * 校验token
         */
        @Around("@annotation(com.x.modules.gcjsy.basic.annoation.ValidateToken)")
        public Object  methodBefore(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
            HttpServletRequest request =  ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
            HttpServletResponse response =  ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getResponse();
            String uuid =  getValue(request);
            if(uuid == null){
                throw new Exception("请刷新重试！");
            }
            UserSession userSession = PermissionHelper.currentUserSession();
            String userId = userSession.getUserId();
            String referer = request.getHeader("referer");
            if(referer!=null){
                referer = referer.substring(referer.indexOf("/c"));
            }
            String key  = PROJ_ST_MENU+uuid+":"+referer+":"+userId;
            Object value = redisTemplate.opsForValue().get(key);
            if(value!=null&&value.equals(referer)){
                try{
                    //此除加锁。如果是分布式系统。更改成分布式锁
                    if(LockHolder.lock.tryLock(10,TimeUnit.SECONDS)){
                        redisTemplate.expire(key,0,TimeUnit.SECONDS);
                        initCookie(response,"",0);
                        return proceedingJoinPoint.proceed(proceedingJoinPoint.getArgs());
                    }
                }catch (Exception e){
                    e.printStackTrace();
                    /**
                     * 异常回滚
                     */
                    initCookie(response,uuid,MAX_AGE);
                    redisTemplate.opsForValue().set(key,referer,MAX_AGE, TimeUnit.SECONDS);
                    throw new Exception("操作异常");
                }finally {
                    LockHolder.lock.unlock();
                }
            }
            logger.error("请不要重复操作");
            return null;
        }
    }
    
    如何使用？

跳转到表单页面增加@GenerateToken注解如下：此页面会自动生成tokenUUID。

![20201117111933585.png][]

进行表单提交方法上增加@ValidateToken注解如下：会进行验证token信息

![20201117112157856.png][]

验证通过。调用方法。验证失败，进行错误提示：

[20201117101236712.png]: /images/20221120/63880a2d662343a5a8c36bfed044674b.png
[20201117111933585.png]: /images/20221120/43fd1698f9fe44f79476187d5c10f21c.png
[20201117112157856.png]: https://img-blog.csdnimg.cn/20201117112157856.png