Spring Boot+React项目PDF流返回超时后出现NaN错误求助

问题描述 #

我开发了一个Spring Boot后端+React前端的应用，功能是把PDF以流的形式返回给浏览器。但当请求到达Controller后处理时长超过1分钟时，页面会显示错误：Error NaN: undefined Reason: undefined。已经尝试增加前端和后端的超时设置，但问题依然存在，不确定是否和超时相关，需要技术支持。

后端日志 #

2023-03-06 12:22:33.678 DEBUG 13380 --- [-nio-443-exec-2] o.s.web.servlet.DispatcherServlet        : GET "/print/error?error=undefined&message=undefined&reason=undefined", parameters={masked}
2023-03-06 12:22:33.680 DEBUG 13380 --- [-nio-443-exec-2] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped to com.jcrew.labelprintbackend.controllers.FrontendController#print()
2023-03-06 12:22:33.682 DEBUG 13380 --- [-nio-443-exec-2] o.s.w.s.v.ContentNegotiatingViewResolver : Selected 'text/html' given [text/html, application/xhtml+xml, image/avif, image/webp, image/apng, application/xml;q=0.9, application/signed-exchange;v=b3;q=0.7, */*;q=0.8]
2023-03-06 12:22:33.682 DEBUG 13380 --- [-nio-443-exec-2] o.s.w.servlet.view.InternalResourceView  : View name 'forward:', model {}
2023-03-06 12:22:33.682 DEBUG 13380 --- [-nio-443-exec-2] o.s.w.servlet.view.InternalResourceView  : Forwarding to [/index.html]
2023-03-06 12:22:33.682 DEBUG 13380 --- [-nio-443-exec-2] o.s.web.servlet.DispatcherServlet        : "FORWARD" dispatch for GET "/index.html?error=undefined&message=undefined&reason=undefined", parameters={masked}
2023-03-06 12:22:33.684 DEBUG 13380 --- [-nio-443-exec-2] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to ResourceHttpRequestHandler [Classpath [META-INF/resources/], Classpath [resources/], Classpath [static/], Classpath [public/], ServletContext [/]]
2023-03-06 12:22:33.687 DEBUG 13380 --- [-nio-443-exec-2] o.s.web.servlet.DispatcherServlet        : Exiting from "FORWARD" dispatch, status 200
2023-03-06 12:22:33.687 DEBUG 13380 --- [-nio-443-exec-2] o.s.web.servlet.DispatcherServlet        : Completed 200 OK
2023-03-06 12:22:33.723 DEBUG 13380 --- [-nio-443-exec-1] o.s.web.servlet.DispatcherServlet        : GET "/static/css/2.eefd091c.chunk.css", parameters={}
2023-03-06 12:22:33.726 DEBUG 13380 --- [-nio-443-exec-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to ResourceHttpRequestHandler [Classpath [META-INF/resources/], Classpath [resources/], Classpath [static/], Classpath [public/], ServletContext [/]]
2023-03-06 12:22:33.766 DEBUG 13380 --- [-nio-443-exec-4] o.s.web.servlet.DispatcherServlet        : GET "/static/js/2.7df57dd0.chunk.js", parameters={}
2023-03-06 12:22:33.767 DEBUG 13380 --- [-nio-443-exec-4] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to ResourceHttpRequestHandler [Classpath [META-INF/resources/], Classpath [resources/], Classpath [static/], Classpath [public/], ServletContext [/]]
2023-03-06 12:22:33.768 DEBUG 13380 --- [-nio-443-exec-1] o.s.web.servlet.DispatcherServlet        : Completed 200 OK
2023-03-06 12:22:33.774 DEBUG 13380 --- [nio-443-exec-10] o.s.web.servlet.DispatcherServlet        : GET "/static/js/main.2f79f0d9.chunk.js", parameters={}
2023-03-06 12:22:33.776 DEBUG 13380 --- [nio-443-exec-10] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to ResourceHttpRequestHandler [Classpath [META-INF/resources/], Classpath [resources/], Classpath [static/], Classpath [public/], ServletContext [/]]
2023-03-06 12:22:33.777 DEBUG 13380 --- [-nio-443-exec-1] o.s.web.servlet.DispatcherServlet        : GET "/static/css/main.bc6778fd.chunk.css", parameters={}
2023-03-06 12:22:33.778 DEBUG 13380 --- [-nio-443-exec-1] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped to ResourceHttpRequestHandler [Classpath [META-INF/resources/], Classpath [resources/], Classpath [static/], Classpath [public/], ServletContext [/]]
2023-03-06 12:22:33.805 DEBUG 13380 --- [nio-443-exec-10] o.s.web.servlet.DispatcherServlet        : Completed 200 OK
2023-03-06 12:22:33.832 DEBUG 13380 --- [-nio-443-exec-1] o.s.web.servlet.DispatcherServlet        : Completed 200 OK
2023-03-06 12:22:33.859 DEBUG 13380 --- [-nio-443-exec-4] o.s.web.servlet.DispatcherServlet        : Completed 200 OK
2023-03-06 12:22:33.927 DEBUG 13380 --- [-nio-443-exec-9] o.s.web.servlet.DispatcherServlet        : GET "/favicon.ico", parameters={}

排查方向与解决方案 #

1. 检查中间件/负载均衡超时 #

如果应用部署在反向代理（如Nginx、Apache）或负载均衡器后面，这些组件默认可能有60秒的超时设置，即使前后端自己设了更长时间，中间件会先断开连接。

• Nginx：修改proxy_connect_timeout、proxy_send_timeout、proxy_read_timeout参数，设置为大于处理时长的值（如300s）
• Apache：调整Timeout、ProxyTimeout参数

2. Spring Boot端深层超时配置 #

除了常规的Controller请求超时，还要检查以下配置：

• 异步请求超时：如果用了@Async处理PDF生成，需要配置spring.task.execution.timeout=300s
• Tomcat连接器超时：在application.properties中设置：

  server.tomcat.connection-timeout=300000
  server.tomcat.keep-alive-timeout=300000
  

3. React端请求处理优化 #

前端的错误提示NaN: undefined通常是请求中断后错误处理逻辑不严谨导致的，需要：

• 确保Axios/Fetch的超时设置正确（以Axios为例）：

  axios({
    method: 'get',
    url: '/api/pdf',
    responseType: 'blob',
    timeout: 300000 // 5分钟
  }).then(response => {
    // 处理PDF流
  }).catch(error => {
    // 完善错误处理，打印完整error对象，排查具体错误原因
    console.error('请求失败:', error);
  });
  

• 检查浏览器本身的超时限制：通过浏览器开发者工具的Network面板查看请求状态（是canceled还是timeout）

4. 长任务异步化优化 #

PDF生成超过1分钟属于长任务，建议改为异步处理：

• 后端提供触发PDF生成的接口，返回任务ID
• 前端轮询任务状态接口，直到任务完成
• 任务完成后，前端再请求PDF流

5. 日志排查补充 #

当前日志只显示了错误页面的跳转，没有原始PDF请求的处理日志，需要添加：

• 在PDF生成的Controller方法中添加日志，记录请求开始、结束时间，以及是否抛出异常
• 查看Tomcat访问日志，确认原始请求的状态码（如504超时、499客户端断开）

内容的提问来源于stack exchange，提问作者Sarthak Mishra