今天學習一下RESTFul api攔截 

         大概有三種方式

過濾器（Filter）         ：可以拿到原始的http請求，但是拿不到你請求的控制器和請求控制器中的方法的資訊。

攔截器（Interceptor）：可以拿到你請求的控制器和方法，卻拿不到請求方法的引數。

切片   （Aspect）       :  可以拿到方法的引數，但是卻拿不到http請求和響應的物件

一、通過Filter這個大家很熟悉了吧,這是java規範的一個過濾器，他會攔截請求。在springboot中一般有兩種配置方式。

        這種過濾器攔截並不知道你用的是哪一個Controller處理也不知道你用哪一個方法處理。

  （1）第一種直接寫類實現這個介面。程式碼如下這個要使用Component註解，當你你請求伺服器的時候他會對每一個請求進行處理。

package com.nbkj.webFilter;

import org.springframework.stereotype.Component;

import javax.servlet.*;
import java.io.IOException;
import java.util.Date;

@Component
public class TimerFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("Time  filter init");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("Time filter start");
        long startTime = new Date().getTime();
        filterChain.doFilter(servletRequest, servletResponse);
        System.out.println("time filter:"+(new Date().getTime()-startTime));
        System.out.println("time filter finish");
    }

    @Override
    public void destroy() {
        System.out.println("Time filter destroy");
    }
}
 

（2）第二種可以在WebConfig中配置，這種配置方式為了使用第三方的Filter沒有@Compont註解所以使用。程式碼如下

package com.nbkj.config;

import com.nbkj.webFilter.TimerFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.ArrayList;
import java.util.List;

/**
 * Web配置
 *
 * @author hsj
 * @Configuration 這個註解宣告這個類是配置類
 * @create 2017-11-11 18:00
 **/

@Configuration
public class WebConfig {
    @Bean
    public FilterRegistrationBean timeFilter() {
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        TimerFilter timerFilter = new TimerFilter();
        registrationBean.setFilter(timerFilter);
        List<String> urls = new ArrayList<>();
        urls.add("/*");
        registrationBean.setUrlPatterns(urls);
        return registrationBean;
    }
}
 

二、使用Interceptor這種事spring框架自己帶的攔截器，程式碼如下 它會處理自己寫的攔截器，也會攔截的攔截BasicErrorController

可以拿到處理的Controller和拿到處理的方法 但是拿不到具體的請求引數。

package com.nbkj.interceptor;

import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.persistence.Convert;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.Date;

/**
 * this is spring interceptor
 *
 * @author hsj
 * @create 2017-11-11 18:16
 **/

@Component
public class TimeInterceptor implements HandlerInterceptor {

    /**
     * 控制器方法處理之前
     *
     * @param httpServletRequest
     * @param httpServletResponse
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler) throws Exception {
        System.out.println("preHandle");
        System.out.println(((HandlerMethod) handler).getBean().getClass().getName());
        System.out.println(((HandlerMethod) handler).getMethod().getName());
        httpServletRequest.setAttribute("startTime", new Date().getTime());
        return false;
    }

    /**
     * 控制器方法處理之後
     * 控制器方法呼叫不拋異常呼叫
     *
     * @param httpServletRequest
     * @param httpServletResponse
     * @param o
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle");
        Long startTime = (Long) httpServletRequest.getAttribute("startTime");
        System.out.println("time interceptor 耗時" + (new Date().getTime() - startTime));
    }

    /**
     * 控制器方法拋不拋異常都會被呼叫
     *
     * @param httpServletRequest
     * @param httpServletResponse
     * @param o
     * @param e
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        System.out.println("afterCompletion");
        Long startTime = (Long) httpServletRequest.getAttribute("startTime");
        System.out.println("time interceptor 耗時" + (new Date().getTime() - startTime));
        System.out.println("ex is" + e);
    }
}

package com.nbkj.config;

import com.nbkj.interceptor.TimeInterceptor;
import com.nbkj.webFilter.TimerFilter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

import java.util.ArrayList;
import java.util.List;

/**
 * Web配置
 *
 * @author hsj
 * @Configuration 這個註解宣告這個類是配置類
 * @create 2017-11-11 18:00
 **/

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

    @Autowired
    private TimeInterceptor timeInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(timeInterceptor);
    }
    
}

三、使用Aspect切片，程式碼如下

   使用環繞通知，切入要切入的類，當請求的時候回攔截下來，這樣可以獲取攔截的方法的引數

package com.nbkj.aspect;


import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;

import java.util.Date;

/**
 * this is a acpect
 * 切入點
 * 在那些方法上起作用
 * 在什麼時候起作用
 *
 * @author hsj
 * @create 2017-11-11 20:52
 **/
@Aspect
@Component
public class TimeAspect {
    @Around("execution(* com.nbkj.controller.UserController.*(..))")
    public Object handleControllerMethod(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
        System.out.println("time aspect start");
        Object[] args = proceedingJoinPoint.getArgs();
        for (Object arg : args) {
            System.out.println(arg.getClass().getName());
            System.out.println("arg is " + arg);
        }
        long startTime = new Date().getTime();
        Object obj = proceedingJoinPoint.proceed();
        System.out.println("time aspect 耗時" + (new Date().getTime() - startTime));
        System.out.println("time aspect end");
        return obj;
    }
}