背景
运行在tomcat容器里的web服务，在响应头信息里，一般都会包含响应状态码，例如：
Status Code: 200 OK
在tomcat 8.5以后，该响应码去掉了状态描述，变成了这样：
Status Code: 200
最近在跟银联的业务往来时，银联要求我们接收到通知后，返回接收结果，并以响应状态码来判断是否解析。这里的状态码就包括状态描述“OK”。
解决
现有系统基于Spring boot 2.3.3.RELEASE，默认tomcat版本为9.x。
- 首先将tomcat版本将为8.5.58，修改pom.xml文件，指定tomcat版本
<properties>
<tomcat.version>8.5.58</tomcat.version>
</properties>
重启应用。发现报错：
***************************
APPLICATION FAILED TO START
***************************
Description:
An attempt was made to call a method that does not exist. The attempt was made from the following location:
org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:175)
The following method did not exist:
org.apache.tomcat.util.modeler.Registry.disableRegistry()V
The method's class, org.apache.tomcat.util.modeler.Registry, is available from the following locations:
jar:file:/Users/admin/org/apache/tomcat/embed/tomcat-embed-core/8.5.58/tomcat-embed-core-8.5.58.jar!/org/apache/tomcat/util/modeler/Registry.class
The class hierarchy was loaded from the following locations:
org.apache.tomcat.util.modeler.Registry: file:/Users/admin/org/apache/tomcat/embed/tomcat-embed-core/8.5.58/tomcat-embed-core-8.5.58.jar
Action:
Correct the classpath of your application so that it contains a single, compatible version of org.apache.tomcat.util.modeler.Registry
Process finished with exit code 1
报错原因就是Spring boot 2.3.3.RELEASE不支持tomcat 8.5，
- 第二步，将Spring boot 版本降低到 2.1.17. RELEASE，或者其他支持tomcat8.5的版本。
- 根据tomcat官方文档描述，在8.5 - 9.0之间的版本中，在“Connector”配置中支持“ sendReasonPhrase”配置参数，可以将状态描述正常返回。
sendReasonPhrase
Set this attribute to true if you wish to have a reason phrase in the response. The default value is false.
Note: This option is deprecated and will be removed in Tomcat 9. The reason phrase will not be sent.
3.1 修改conf/server.xml文件，适用于外置tomcat
<Connector port="8080" protocol="org.apache.coyote.ajp.AjpAprProtocol" redirectPort="8443" sendReasonPhrase="true" />
3.2 Spring boot代码配置，适用于内置tomcat
@Bean
public ConfigurableServletWebServerFactory webServerFactory() {
TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();
factory.addConnectorCustomizers(
connector -> connector.setAttribute("sendReasonPhrase", "true"));
return factory;
}
参考链接：
https://bz.apache.org/bugzilla/show_bug.cgi?id=60362
https://tomcat.apache.org/tomcat-8.5-doc/config/http.html
https://stackoverflow.com/questions/40034949/add-reason-phrase-back-in-spring-boot-1-4-x
