SpringBoot 统计API接口用时该使用过滤器还是拦截器?

统计请求的处理时间（用时）既可以使用 Servlet 过滤器（Filter），也可以使用 Spring 拦截器（Interceptor）。两者都可以在请求处理前后插入自定义逻辑，从而实现对请求响应时间的统计。

使用建议

如果你需要在更底层、与框架无关的地方记录所有请求（包括静态资源请求）的处理时间，那么 Servlet 过滤器是一个更好的选择。

如果你正在使用 Spring MVC 并且关注的是 Controller 层的处理时间，或者需要访问到 Spring 上下文中的服务，那么 Spring 拦截器可能更为合适。

代码样例

Servlet 过滤器（Filter）

import jakarta.servlet.*;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import java.io.IOException;
import java.time.Instant;

@Component
@Slf4j
public class LogFilter implements Filter {
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        System.err.println("***LogFilter.doFilter.start***");
        HttpServletRequest httpReq = (HttpServletRequest) request;
        long startTime = Instant.now().toEpochMilli();

        // 记录请求开始时间及请求信息
        log.warn("LogFilter.doFilter: Start processing request at {} - {}", Instant.now(), httpReq.getRequestURI());

        try {
            // 将请求传递给下一个过滤器或目标资源
            chain.doFilter(request, response);
        } finally {
            // 记录请求结束时间及响应状态码
            long endTime = Instant.now().toEpochMilli();
            int statusCode = ((HttpServletResponse) response).getStatus();
            log.warn("LogFilter.doFilter: Finished processing request at {} - {} in {} ms. Status code: {}", Instant.now(), httpReq.getRequestURI(), (endTime - startTime), statusCode);
        }
        System.err.println("***LogFilter.doFilter.end***");
    }
}

Spring 拦截器（Interceptor）

import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import java.time.Instant;

@Component
@Slf4j
public class LogInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        System.err.println("***LogInterceptor.preHandle***");
        long startTime = Instant.now().toEpochMilli();
        request.setAttribute("startTime", startTime);
        log.warn("LogInterceptor.postHandle: Start processing request at {} - {}", Instant.now(), request.getRequestURI());
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
        System.err.println("***LogInterceptor.preHandle***");
        // 获取请求开始时间
        Long startTime = (Long) request.getAttribute("startTime");
        if (startTime != null) {
            long executionTime = Instant.now().toEpochMilli() - startTime;
            int statusCode = response.getStatus();
            log.warn("LogInterceptor.postHandle: Finished processing request at {} - {} in {} ms. Status code: {}", Instant.now(), request.getRequestURI(), executionTime, statusCode);
        }
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.err.println("***LogInterceptor.afterCompletion***");
        // 在此可以添加额外的后处理逻辑，但本例中我们不需要
    }
}

测试验证

# 过滤器开始计时
***LogFilter.doFilter.start***
[2024-01-17 08:17:55] [WARN ] [http-nio-8080-exec-2] [LogFilter.java:22] → [LogFilter.doFilter: Start processing request at 2024-01-17T00:17:55.662652400Z - /students]
***RequestHeaderCheckFilter.doFilter.start***

# 拦截器组的 preHandle
***ResponsePostInterceptor.preHandle***
# log用时拦截器开始计时
***LogInterceptor.preHandle***
[2024-01-17 08:17:55] [WARN ] [http-nio-8080-exec-2] [LogInterceptor.java:20] → [LogInterceptor.postHandle: Start processing request at 2024-01-17T00:17:55.852229500Z - /students]

# Controller层
***StudentController.edit***
[2024-01-17 08:17:56] [INFO ] [http-nio-8080-exec-2] [HikariDataSource.java:110] → [practisedb - Starting...]
[2024-01-17 08:17:56] [INFO ] [http-nio-8080-exec-2] [HikariPool.java:565] → [practisedb - Added connection com.mysql.cj.jdbc.ConnectionImpl@34a6ebfc]
[2024-01-17 08:17:56] [INFO ] [http-nio-8080-exec-2] [HikariDataSource.java:123] → [practisedb - Start completed.]

# @ControllerAdvice对Response增强，比如修改状态码，补充header值
***ResponsePostAdvice.supports***
***ResponsePostAdvice.beforeBodyWrite***

# 拦截器组的 postHandle
***LogInterceptor.postHandle***
# log用时拦截器结束计时
[2024-01-17 08:17:56] [WARN ] [http-nio-8080-exec-2] [LogInterceptor.java:32] → [LogInterceptor.postHandle: Finished processing request at 2024-01-17T00:17:56.636557900Z - /students in 784 ms. Status code: 200]
***ResponsePostInterceptor.postHandle***

# 拦截器组的 afterCompletion
***LogInterceptor.afterCompletion***
***ResponsePostInterceptor.afterCompletion***

# 过滤器结束计时
***RequestHeaderCheckFilter.doFilter.end***
[2024-01-17 08:17:56] [WARN ] [http-nio-8080-exec-2] [LogFilter.java:31] → [LogFilter.doFilter: Finished processing request at 2024-01-17T00:17:56.920165800Z - /students in 1258 ms. Status code: 200]
***LogFilter.doFilter.end***