解决重复提交表单的解决

一. 利用拦截器+注解+session的方式解决
主要思路：

1. 写一个可以在控制器方法上用的注解比如RepeatSubmit

@Inherited
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface RepeatSubmit
{

}

2. 写一个拦截器，用来拦截重复提交的请求

@Component
public abstract class RepeatSubmitInterceptor extends HandlerInterceptorAdapter
{
    @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))
                {
                    AjaxResult ajaxResult = AjaxResult.error("不允许重复提交，请稍后再试");
                    ServletUtils.renderString(response, JSON.marshal(ajaxResult));
                    return false;
                }
            }
            return true;
        }
        else
        {
            return super.preHandle(request, response, handler);
        }
    }

    /**
     * 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) throws Exception;
}

3. 利用session来判断是否为规定时间内发出了重复的请求

@Component
public class SameUrlDataInterceptor extends RepeatSubmitInterceptor
{
    public final String REPEAT_PARAMS = "repeatParams";

    public final String REPEAT_TIME = "repeatTime";

    public final String SESSION_REPEAT_KEY = "repeatData";

    /**
     * 间隔时间，单位:秒 默认10秒
     *
     * 两次相同参数的请求，如果间隔时间大于该参数，系统不会认定为重复提交的数据
     */
    private int intervalTime = 10;

    public void setIntervalTime(int intervalTime)
    {
        this.intervalTime = intervalTime;
    }

    @SuppressWarnings("unchecked")
    @Override
    public boolean isRepeatSubmit(HttpServletRequest request) throws Exception
    {
        // 本次参数及系统时间
        String nowParams = JSON.marshal(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session的key值）
        String url = request.getRequestURI();

        HttpSession session = request.getSession();
        Object sessionObj = session.getAttribute(SESSION_REPEAT_KEY);
        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))
                {
                    return true;
                }
            }
        }
        Map<String, Object> sessionMap = new HashMap<String, Object>();
        sessionMap.put(url, nowDataMap);
        session.setAttribute(SESSION_REPEAT_KEY, sessionMap);
        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)
    {
        long time1 = (Long) nowMap.get(REPEAT_TIME);
        long time2 = (Long) preMap.get(REPEAT_TIME);
        if ((time1 - time2) < (this.intervalTime * 1000))
        {
            return true;
        }
        return false;
    }
}