有时候我们在保存数据后，页面提示400错误，如下图，server日志文件里打印如下错误信息

2025-08-19 08:37:36.879 [http-nio-9999-exec-3] INFO org.apache.coyote.http11.Http11Processor - Error parsing HTTP request header Note: further occurrences of HTTP request parsing errors will be logged at DEBUG level. java.lang.IllegalArgumentException: Request header is too large at org.apache.coyote.http11.Http11InputBuffer.fill(Http11InputBuffer.java:781) at org.apache.coyote.http11.Http11InputBuffer.parseRequestLine(Http11InputBuffer.java:445) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:269) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:937) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1793) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1190) at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63) at java.lang.Thread.run(Unknown Source)

我们如何处理这个错误呢？

我们只需要在server的配置文件（server/config/application.yml）中，添加一个参数就好了

在port上面添加如下参数max-http-form-post-size和max-http-header-size，注意左对齐，添加完成后重启server程序就可以生效了

server: max-http-header-size: 10MB tomcat: max-http-form-post-size: 100MB port: 9999

提示，v3.6.2版本开始，配置文件里默认内置了这两个参数，如果不够用，直接修改值就可以了