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【java】拦截器的应用

本文主要是介绍【java】拦截器的应用,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!

重复提交拦截器(学习诺依框架)

HandlerInterceptor

拦截器我想大家都并不陌生,最常用的登录拦截、或是权限校验、或是防重复提交、或是根据业务校验。

RepeatSubmitInterceptor

import java.lang.reflect.Method;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import com.ruoyi.common.json.JSON;
import com.ruoyi.common.annotation.RepeatSubmit;
import com.ruoyi.common.core.domain.AjaxResult;
import com.ruoyi.common.utils.ServletUtils;

/**
 * 防止重复提交拦截器
 *
 * @author ruoyi
 */
@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))
                {
                    AjaxResult ajaxResult = AjaxResult.error(annotation.message());
                    ServletUtils.renderString(response, JSON.marshal(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 请求对象
     * @param annotation 防复注解
     * @return 结果
     */
    public abstract boolean isRepeatSubmit(HttpServletRequest request, RepeatSubmit annotation) throws Exception;
}

SameUrlDataInterceptor实现

import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.springframework.stereotype.Component;
import com.ruoyi.common.annotation.RepeatSubmit;
import com.ruoyi.common.json.JSON;
import com.ruoyi.framework.interceptor.RepeatSubmitInterceptor;

/**
 * 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10秒内。
 * 
 * @author ruoyi
 */
@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";

    @SuppressWarnings("unchecked")
    @Override
    public boolean isRepeatSubmit(HttpServletRequest request, RepeatSubmit annotation) 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, annotation.interval()))
                {
                    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, int interval)
    {
        long time1 = (Long) nowMap.get(REPEAT_TIME);
        long time2 = (Long) preMap.get(REPEAT_TIME);
        if ((time1 - time2) < interval)
        {
            return true;
        }
        return false;
    }
}

ResourcesConfig

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import com.ruoyi.common.config.RuoYiConfig;
import com.ruoyi.common.constant.Constants;
import com.ruoyi.framework.interceptor.RepeatSubmitInterceptor;

/**
 * 通用配置
 * 
 * @author ruoyi
 */
@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("/**");
    }
}
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