使用Spring MVC开发RESTful API的拦截功能

详细代码见我的github仓库 https://github.com/29DCH/springsecurity-study 欢迎star+fork

RESTful API的拦截功能实现
拦截顺序图:

这里统一用请求方法耗时的例子来讲
1.过滤器(Filter)

package com.ljq.web.filter;

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

/**
 * @author ljq
 *
 */
@Component
public class TimeFilter implements Filter {

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

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		System.out.println("time filter start");
		long start = new Date().getTime();
		chain.doFilter(request, response);
		System.out.println("time filter 耗时:"+ (new Date().getTime() - start));
		System.out.println("time filter finish");
	}

	@Override
	public void init(FilterConfig arg0) throws ServletException {
		System.out.println("time filter init");
	}

}

如果这里不加@Component注解,这时类似于自定义的第三方过滤器,需要加配置文件(springboot里面不用XML配置).

WebConfig.java

package com.ljq.web.config;

import com.ljq.web.filter.TimeFilter;
import com.ljq.web.interceptor.TimeInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
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;

/**
 * @author ljq
 */
@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

    @SuppressWarnings("unused")
    @Autowired
    private TimeInterceptor timeInterceptor;

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

    @Bean
    public FilterRegistrationBean timeFilter() {

        FilterRegistrationBean registrationBean = new FilterRegistrationBean();

        TimeFilter timeFilter = new TimeFilter();
        registrationBean.setFilter(timeFilter);

        List<String> urls = new ArrayList<>();
        urls.add("/*");
        registrationBean.setUrlPatterns(urls);

        return registrationBean;

    }

}

优点:能够自定义拦截url,拦截范围广
缺点:无法准确知道拦截的控制器和方法所在位置

2.拦截器(Interceptor)
spring框架本身提供的,能够准确知道拦截的控制器和方法所在位置

package com.ljq.web.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.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.Date;

/**
 * @author ljq
 */
@Component
public class TimeInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        System.out.println("preHandle");
       //打印出控制器和方法名称
        System.out.println(((HandlerMethod) handler).getBean().getClass().getName());
        System.out.println(((HandlerMethod) handler).getMethod().getName());

        request.setAttribute("startTime", new Date().getTime());
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
                           ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle");
        Long start = (Long) request.getAttribute("startTime");
        System.out.println("time interceptor 耗时:" + (new Date().getTime() - start));

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        System.out.println("afterCompletion");
        Long start = (Long) request.getAttribute("startTime");
        System.out.println("time interceptor 耗时:" + (new Date().getTime() - start));
        System.out.println("ex is " + ex);

    }

}

配置代码见上文的WebConfig.java

优点:能够准确知道拦截的控制器(自定义的或者spring框架提供的)和方法所在位置
缺点:无法知道方法参数的值

3.切片(Aspect)
Spring AOP编程,面向切面编程
好处:知道方法参数的值

package com.ljq.web.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;

/**
 * @author ljq
 *
 */
@Aspect
@Component
public class TimeAspect {
	
	@Around("execution(* com.ljq.web.controller.UserController.*(..))")
	public Object handleControllerMethod(ProceedingJoinPoint pjp) throws Throwable {
		
		System.out.println("time aspect start");
		
		Object[] args = pjp.getArgs();
		for (Object arg : args) {
			System.out.println("arg is "+arg);
		}
		
		long start = new Date().getTime();
		
		Object object = pjp.proceed();
		
		System.out.println("time aspect 耗时:"+ (new Date().getTime() - start));
		
		System.out.println("time aspect end");
		
		return object;
	}

}