日常开发中我们经常会遇到前端多次请求同一个接口的问题,比如前端没有做遮罩层,用户点击了多次按钮。全指望着用户来等待也并不靠谱,如果各个接口自己进行防止重复提交的逻辑又显得不是十分优雅了,所以,我们就将对应的逻辑抽出来形成一个注解,方便我们的使用。

设计思路

根据提交的参数跟间隔时间到缓存中查询,判断两次提交的参数是否相同,如果相同且在间隔时间内则算作是重复提交

RepeatSubmit注解

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/**
 * 自定义注解防止表单重复提交
 *
 * @author 7bin
 * @date 2023/06/13
 */
@Inherited
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface RepeatSubmit
{
    /**
     * 间隔时间(ms),小于此时间视为重复提交
     */
    public int interval() default 5000;

    /**
     * 提示消息
     */
    public String message() default "不允许重复提交,请稍候再试";
}

定义拦截器

首先我们定义了一个抽象类RepeatSubmitInterceptor,对preHandle方法进行了定义,判断方法上是否存在RepeatSubmit 注解

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@Component
public abstract class RepeatSubmitInterceptor implements HandlerInterceptor
{
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception
    {
        if (handler instanceof HandlerMethod)
        {
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            Method method = handlerMethod.getMethod();
            RepeatSubmit annotation = method.getAnnotation(RepeatSubmit.class);
            if (annotation != null)
            {
                if (this.isRepeatSubmit(request, annotation))
                {
                    ApiResponse ajaxResult = ApiResponse.error(annotation.message());
                    ServletUtils.renderString(response, JSON.toJSONString(ajaxResult));
                    return false;
                }
            }
            return true;
        }
        else
        {
            return true;
        }
    }

    /**
     * 验证是否重复提交由子类实现具体的防重复提交的规则
     *
     * @param request
     * @return
     * @throws Exception
     */
    public abstract boolean isRepeatSubmit(HttpServletRequest request, RepeatSubmit annotation);
}

子类中实现父类的isRepeatSubmit方法

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/**
 * 判断请求url和数据是否和上一次相同,
 * 如果和上次相同,则是重复提交表单。 有效时间为5秒内。
 */
@Component
public class SameUrlDataInterceptor extends RepeatSubmitInterceptor
{
    public final String REPEAT_PARAMS = "repeatParams";

    public final String REPEAT_TIME = "repeatTime";

    // 令牌自定义标识
    @Value("${token.header}")
    private String header;

    @Autowired
    private RedisCache redisCache;

    @SuppressWarnings("unchecked")
    @Override
    public boolean isRepeatSubmit(HttpServletRequest request, RepeatSubmit annotation)
    {
        String nowParams = "";
        if (request instanceof RepeatedlyRequestWrapper)
        {
            RepeatedlyRequestWrapper repeatedlyRequest = (RepeatedlyRequestWrapper) request;
            nowParams = HttpHelper.getBodyString(repeatedlyRequest);
        }

        // body参数为空,获取Parameter的数据
        if (StringUtils.isEmpty(nowParams))
        {
            nowParams = JSON.toJSONString(request.getParameterMap());
        }
        Map<String, Object> nowDataMap = new HashMap<String, Object>();
        nowDataMap.put(REPEAT_PARAMS, nowParams);
        nowDataMap.put(REPEAT_TIME, System.currentTimeMillis());

        // 请求地址(作为存放cache的key值)
        String url = request.getRequestURI();

        // 唯一值(没有消息头则使用请求地址)
        String submitKey = StringUtils.trimToEmpty(request.getHeader(header));

        // 唯一标识(指定key + url + 消息头)
        String cacheRepeatKey = CacheConstants.REPEAT_SUBMIT_KEY + url + "/" + submitKey;

        Object sessionObj = redisCache.getCacheObject(cacheRepeatKey);
        if (sessionObj != null)
        {
            Map<String, Object> sessionMap = (Map<String, Object>) sessionObj;
            if (sessionMap.containsKey(url))
            {
                Map<String, Object> preDataMap = (Map<String, Object>) sessionMap.get(url);
                if (compareParams(nowDataMap, preDataMap) && compareTime(nowDataMap, preDataMap, annotation.interval()))
                {
                    return true;
                }
            }
        }
        Map<String, Object> cacheMap = new HashMap<String, Object>();
        cacheMap.put(url, nowDataMap);
        redisCache.set(cacheRepeatKey, cacheMap, annotation.interval(), TimeUnit.MILLISECONDS);
        return false;
    }

    /**
     * 判断参数是否相同
     */
    private boolean compareParams(Map<String, Object> nowMap, Map<String, Object> preMap)
    {
        String nowParams = (String) nowMap.get(REPEAT_PARAMS);
        String preParams = (String) preMap.get(REPEAT_PARAMS);
        return nowParams.equals(preParams);
    }

    /**
     * 判断两次间隔时间
     */
    private boolean compareTime(Map<String, Object> nowMap, Map<String, Object> preMap, int interval)
    {
        long time1 = (Long) nowMap.get(REPEAT_TIME);
        long time2 = (Long) preMap.get(REPEAT_TIME);
        if ((time1 - time2) < interval)
        {
            return true;
        }
        return false;
    }
}

值得注意的一个地方

为什么前面要带一个url拼接submitKey(token)呢?

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// 唯一值(没有消息头则使用请求地址)
String submitKey = StringUtils.trimToEmpty(request.getHeader(header));

// 唯一标识(指定key + url + 消息头)
String cacheRepeatKey = CacheConstants.REPEAT_SUBMIT_KEY + url + "/" + submitKey;

原因是有的时候并不是所有的请求都有token,这个时候如果我们不对对应的url进行拦截的话,那么他们就可以在未登录的情况下对某些无需登录却十分耗时的页面进行多次请求,而如果对url也进行了拦截,就不会有这个问题了。可以对这个url的访问次数进行限制了。

注册拦截器

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@Configuration
public class ResourcesConfig implements WebMvcConfigurer
{
    @Autowired
    private RepeatSubmitInterceptor repeatSubmitInterceptor;

    
    /**
     * 自定义拦截规则
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry)
    {
        registry.addInterceptor(repeatSubmitInterceptor).addPathPatterns("/**");
    }
}

注册过滤器

构建可重复读取inputStream的request

FilterConfig

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@Configuration
public class FilterConfig
{

    @SuppressWarnings({ "rawtypes", "unchecked" })
    @Bean
    public FilterRegistrationBean someFilterRegistration()
    {
        FilterRegistrationBean registration = new FilterRegistrationBean();
        registration.setFilter(new RepeatableFilter());
        registration.addUrlPatterns("/*");
        registration.setName("repeatableFilter");
        registration.setOrder(FilterRegistrationBean.LOWEST_PRECEDENCE);
        return registration;
    }

}

RepeatableFilter

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/**
 * Repeatable 过滤器
 * 
 * @author 7bin
 */
public class RepeatableFilter implements Filter
{
    @Override
    public void init(FilterConfig filterConfig) throws ServletException
    {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException
    {
        ServletRequest requestWrapper = null;
        if (request instanceof HttpServletRequest
                && StringUtils.startsWithIgnoreCase(request.getContentType(), MediaType.APPLICATION_JSON_VALUE))
        {
            requestWrapper = new RepeatedlyRequestWrapper((HttpServletRequest) request, response);
        }
        if (null == requestWrapper)
        {
            chain.doFilter(request, response);
        }
        else
        {
            chain.doFilter(requestWrapper, response);
        }
    }

    @Override
    public void destroy()
    {

    }
}

RepeatedlyRequestWrapper

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/**
 * 构建可重复读取inputStream的request
 * 
 * @author 7bin
 */
public class RepeatedlyRequestWrapper extends HttpServletRequestWrapper
{
    private final byte[] body;

    public RepeatedlyRequestWrapper(HttpServletRequest request, ServletResponse response) throws IOException
    {
        super(request);
        request.setCharacterEncoding(Constants.UTF8);
        response.setCharacterEncoding(Constants.UTF8);

        body = HttpHelper.getBodyString(request).getBytes(Constants.UTF8);
    }

    @Override
    public BufferedReader getReader() throws IOException
    {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    @Override
    public ServletInputStream getInputStream() throws IOException
    {
        final ByteArrayInputStream bais = new ByteArrayInputStream(body);
        return new ServletInputStream()
        {
            @Override
            public int read() throws IOException
            {
                return bais.read();
            }

            @Override
            public int available() throws IOException
            {
                return body.length;
            }

            @Override
            public boolean isFinished()
            {
                return false;
            }

            @Override
            public boolean isReady()
            {
                return false;
            }

            @Override
            public void setReadListener(ReadListener readListener)
            {

            }
        };
    }
}

注解使用

在controller中对需要设置防重复提交的方法加上@RepeatSubmit

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/**
 * 修改用户
 */
@RepeatSubmit
@PutMapping("/profile")
public ApiResponse updateProfile(@RequestBody SysUser user)
{
    ...
}