springMVC 防重校验(拦截器)[通俗易懂]

<mvc:interceptor>
    <mvc:mapping path="/**"/>
    <bean class="com.bitspace.bourse.core.interceptor.NoRepeatInterceptor"></bean>
</mvc:interceptor>

import com.alibaba.fastjson.JSON;
import com.bitspace.bourse.core.annotation.NoRepeatData;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

public class NoRepeatInterceptor extends HandlerInterceptorAdapter {
  
  

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
  
  
        if (handler instanceof HandlerMethod) {
  
  
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            Method method = handlerMethod.getMethod();
            NoRepeatData annotation = method.getAnnotation(NoRepeatData.class);
            if (annotation != null) {
  
  
                if (repeatDataValidator(request)) {//如果重复相同数据
                    return false;
                } else {
  
  
                    return true;
                }
            }
            return true;
        } else {
  
  
            return super.preHandle(request, response, handler);
        }
    }

    public boolean repeatDataValidator(HttpServletRequest httpServletRequest) {
  
  
        String params = JSON.toJSONString(httpServletRequest.getParameterMap());
        String url = httpServletRequest.getRequestURI();
        Map<String, String> map = new HashMap<String, String>();
        map.put(url, params);
        String nowUrlParams = map.toString();

        Object preUrlParams = httpServletRequest.getSession().getAttribute("repeatData");
        if (preUrlParams == null) {//如果上一个数据为null,表示还没有访问页面
            httpServletRequest.getSession().setAttribute("repeatData", nowUrlParams);
            return false;
        } else {//否则，已经访问过页面
            if (preUrlParams.toString().equals(nowUrlParams)) {//如果上次url+数据和本次url+数据相同，则表示城府添加数据
                return true;
            } else {//如果上次 url+数据 和本次url加数据不同，则不是重复提交
                httpServletRequest.getSession().setAttribute("repeatData", nowUrlParams);
                return false;
            }

        }

    }

}

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface NoRepeatData {
  
  
}