使用 Spring MVC HandlerInterceptorAdapter 从 HttpServletResponse 记录响应正文 (HTML)

Question

我正在尝试记录（为了简单起见，现在只是为了控制台编写）将由 HttpServletResponse 返回的最终呈现的 HTML。 （即主体）为此，我使用 Spring MVC 中的 HandlerInterceptorAdapter，如下所示：

public class VxmlResponseInterceptor extends HandlerInterceptorAdapter {
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println(response.toString());
    }
}

这按预期工作，我在控制台中看到了 HTTP 响应标头。我的问题是，是否有一种相对简单的方法可以将整个响应正文（即最终呈现的 HTML）记录到控制台，而不必求助于 PrintWriter、OutputStream 等。

提前致谢。

Answer 1

最好使用 Servlet Filter 而不是 Spring HandlerInterceptor 来完成，因为允许 Filter 替换请求和/或响应对象，您可以使用此机制来替换带有记录响应输出的包装器的响应。

这将涉及编写HttpServletResponseWrapper 的子类，覆盖getOutputStream（可能还有getWriter()）。这些方法将返回OutputStream/PrintWriter 实现，这些实现将响应流虹吸到日志中，除了发送到其原始目的地。一个简单的方法是使用Apache Commons IO 中的TeeOutputStream，但自己实现并不难。

这里有一个你可以做的事情的例子，利用 Spring 的 GenericFilterBean 和 DelegatingServletResponseStream 以及 TeeOutputStream，让事情变得更容易：

public class ResponseLoggingFilter extends GenericFilterBean {

   @Override
   public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
      HttpServletResponse responseWrapper = loggingResponseWrapper((HttpServletResponse) response);     
      filterChain.doFilter(request, responseWrapper);
   }

   private HttpServletResponse loggingResponseWrapper(HttpServletResponse response) {
      return new HttpServletResponseWrapper(response) {
         @Override
         public ServletOutputStream getOutputStream() throws IOException {
            return new DelegatingServletOutputStream(
               new TeeOutputStream(super.getOutputStream(), loggingOutputStream())
            );
         }
      };
   }

   private OutputStream loggingOutputStream() {
      return System.out;
   }
}

这会将所有内容记录到 STDOUT。如果你想记录到一个文件，它会变得更复杂，确保流被关闭等等，但原理保持不变。

Answer 2

如果您正在使用（或考虑）logback 作为您的日志记录框架，那么已经有一个很好的 servlet 过滤器可以做到这一点。查看documentation 中的 TeeFilter 章节。

Answer 3

一段时间以来，我一直在寻找一种记录完整 HTTP 请求/响应的方法，并发现它已在 Tomcat 7 RequestDumperFilter 中为我解决了。它的工作原理与 Tomcat 7 容器所宣传的一样。如果您想在 Jetty 中使用它，该类可以独立运行，或者像我一样，复制并适应我的环境的特定需求。

Answer 4

我通过 maven Central 创建了一个小型库 spring-mvc-logger。

添加到 pom.xml：

<dependency>
    <groupId>com.github.isrsal</groupId>
    <artifactId>spring-mvc-logger</artifactId>
    <version>0.2</version>
</dependency>

添加到 web.xml：

<filter>
    <filter-name>loggingFilter</filter-name>
    <filter-class>com.github.isrsal.logging.LoggingFilter</filter-class>
</filter>

<filter-mapping>
    <filter-name>loggingFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

添加到 log4j.xml：

<logger name="com.github.isrsal.logging.LoggingFilter">
    <level value="DEBUG"/>
</logger>

Answer 5

下面粘贴的代码适用于我的测试，可以从我的github project 下载，在应用基于生产项目的解决方案后分享

    @Configuration
public class LoggingFilter extends GenericFilterBean {

    /**
     * It's important that you actually register your filter this way rather then just annotating it
     * as @Component as you need to be able to set for which "DispatcherType"s to enable the filter
     * (see point *1*)
     * 
     * @return
     */
    @Bean
    public FilterRegistrationBean<LoggingFilter> initFilter() {
        FilterRegistrationBean<LoggingFilter> registrationBean = new FilterRegistrationBean<>();
        registrationBean.setFilter(new LoggingFilter());

        // *1* make sure you sett all dispatcher types if you want the filter to log upon
        registrationBean.setDispatcherTypes(EnumSet.allOf(DispatcherType.class));

        // *2* this should put your filter above any other filter
        registrationBean.setOrder(Ordered.HIGHEST_PRECEDENCE);

        return registrationBean;
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {

        ContentCachingRequestWrapper wreq = 
            new ContentCachingRequestWrapper(
                (HttpServletRequest) request);

        ContentCachingResponseWrapper wres = 
            new ContentCachingResponseWrapper(
                (HttpServletResponse) response);

        try {

            // let it be ...
            chain.doFilter(wreq, wres);

            // makes sure that the input is read (e.g. in 404 it may not be)
            while (wreq.getInputStream().read() >= 0);

            System.out.printf("=== REQUEST%n%s%n=== end request%n",
                    new String(wreq.getContentAsByteArray()));

            // Do whatever logging you wish here, in this case I'm writing request 
            // and response to system out which is probably not what you wish to do
            System.out.printf("=== RESPONSE%n%s%n=== end response%n",
                    new String(wres.getContentAsByteArray()));

            // this is specific of the "ContentCachingResponseWrapper" we are relying on, 
            // make sure you call it after you read the content from the response
            wres.copyBodyToResponse();

            // One more point, in case of redirect this will be called twice! beware to handle that
            // somewhat

        } catch (Throwable t) {
            // Do whatever logging you whish here, too
            // here you should also be logging the error!!!
            throw t;
        }

    }
}