本文记录一下springboot日志打印的三种方式，过滤器、拦截器、AOP

一、过滤器
创建LogFilter类实现Filter接口

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

@Component
public class LogFilter implements Filter {

    private static final Logger LOG = LoggerFactory.getLogger(LogFilter.class);

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        // 打印请求信息
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        LOG.info("------------- LogFilter 开始 -------------");
        LOG.info("请求地址: {} {}", request.getRequestURL().toString(), request.getMethod());
        LOG.info("远程地址: {}", request.getRemoteAddr());

        long startTime = System.currentTimeMillis();
        filterChain.doFilter(servletRequest, servletResponse);
        LOG.info("------------- LogFilter 结束 耗时：{} ms -------------", System.currentTimeMillis() - startTime);
    }
}

二、拦截器
（1）创建LogInterceptor类实现HandlerInterceptor接口

import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.stereotype.Component;
 import org.springframework.web.servlet.HandlerInterceptor;
 import org.springframework.web.servlet.ModelAndView;

 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 /**
  * 拦截器：Spring框架特有的，常用于登录校验，权限校验，请求日志打印 /login
  */
 @Component
 public class LogInterceptor implements HandlerInterceptor {

     private static final Logger LOG = LoggerFactory.getLogger(LogInterceptor.class);

     @Override
     public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
         // 打印请求信息
         LOG.info("------------- LogInterceptor 开始 -------------");
         LOG.info("请求地址: {} {}", request.getRequestURL().toString(), request.getMethod());
         LOG.info("远程地址: {}", request.getRemoteAddr());

         long startTime = System.currentTimeMillis();
         request.setAttribute("requestStartTime", startTime);
         return true;
     }

     @Override
     public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
         long startTime = (Long) request.getAttribute("requestStartTime");
         LOG.info("------------- LogInterceptor 结束 耗时：{} ms -------------", System.currentTimeMillis() - startTime);
     }
 }

（2）创建SpringMvcConfig配置类实现WebMvcConfigurer接口，将上述类注册到配置类中

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import javax.annotation.Resource;

@Configuration
public class SpringMvcConfig implements WebMvcConfigurer {

    @Resource
    LogInterceptor logInterceptor;

    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(logInterceptor)
                .addPathPatterns("/**")
                .excludePathPatterns();
    }

}

三、AOP
（1）打开pom.xml，添加AOP依赖

		<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

（2）添加fastjson依赖，对于本代码来说是必须的，因为本代码在使用AOP时想要排除敏感字段，需要fastjson下的JSONObject。如果只是单纯的使用AOP是不需要这个依赖的

		<dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.70</version>
        </dependency>

（3）创建LogAspect类

import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.support.spring.PropertyPreFilters;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.Signature;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

@Aspect
@Component
public class LogAspect {

    private final static Logger LOG = LoggerFactory.getLogger(LogAspect.class);

    /** 定义一个切点 */
    @Pointcut("execution(public * com.jiawa.*.controller..*Controller.*(..))")
    public void controllerPointcut() {}

    @Before("controllerPointcut()")
    public void doBefore(JoinPoint joinPoint) throws Throwable {

        // 开始打印请求日志
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        Signature signature = joinPoint.getSignature();
        String name = signature.getName();

        // 打印请求信息
        LOG.info("------------- 开始 -------------");
        LOG.info("请求地址: {} {}", request.getRequestURL().toString(), request.getMethod());
        LOG.info("类名方法: {}.{}", signature.getDeclaringTypeName(), name);
        LOG.info("远程地址: {}", request.getRemoteAddr());

        // 打印请求参数
        Object[] args = joinPoint.getArgs();
		// LOG.info("请求参数: {}", JSONObject.toJSONString(args));

		Object[] arguments  = new Object[args.length];
        for (int i = 0; i < args.length; i++) {
            if (args[i] instanceof ServletRequest
                    || args[i] instanceof ServletResponse
                    || args[i] instanceof MultipartFile) {
                continue;
            }
            arguments[i] = args[i];
        }
        // 排除字段，敏感字段或太长的字段不显示
        String[] excludeProperties = {"password", "file"};
        PropertyPreFilters filters = new PropertyPreFilters();
        PropertyPreFilters.MySimplePropertyPreFilter excludefilter = filters.addFilter();
        excludefilter.addExcludes(excludeProperties);
        LOG.info("请求参数: {}", JSONObject.toJSONString(arguments, excludefilter));
    }

    @Around("controllerPointcut()")
    public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
        long startTime = System.currentTimeMillis();

//        执行业务
        Object result = proceedingJoinPoint.proceed();

        // 排除字段，敏感字段或太长的字段不显示
        String[] excludeProperties = {"password", "file"};
        PropertyPreFilters filters = new PropertyPreFilters();
        PropertyPreFilters.MySimplePropertyPreFilter excludefilter = filters.addFilter();
        excludefilter.addExcludes(excludeProperties);
        LOG.info("返回结果: {}", JSONObject.toJSONString(result, excludefilter));
        LOG.info("------------- 结束 耗时：{} ms -------------", System.currentTimeMillis() - startTime);
        return result;
    }

    /**
     * 使用nginx做反向代理，需要用该方法才能取到真实的远程IP
     * @param request
     * @return
     */
    public String getRemoteIp(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        return ip;
    }

}