为什么春天会覆盖标题中的Content-Type？

Question

我以这种方式在Controller中设置http标头后：

@Controller
@Slf4j
public class PlayerController {    
    @ModelAttribute
    public void setVaryResponseHeader(HttpServletResponse response) {
        response.setHeader("Content-Type", "application/vnd.apple.mpegurl");
    }

    @ResponseBody
    @RequestMapping(value = "/live/timeshift.m3u8", method = RequestMethod.GET)
    public String playbackLive(@RequestParam(value = "delay") Integer delay) {
        ....
    }
}

然后，Spring将其覆盖为纯文本

writeWithMessageConverters:184, AbstractMessageConverterMethodProcessor (org.springframework.web.servlet.mvc.method.annotation)
handleReturnValue:174, RequestResponseBodyMethodProcessor (org.springframework.web.servlet.mvc.method.annotation)
handleReturnValue:81, HandlerMethodReturnValueHandlerComposite (org.springframework.web.method.support)
invokeAndHandle:113, ServletInvocableHandlerMethod (org.springframework.web.servlet.mvc.method.annotation)
invokeHandlerMethod:854, RequestMappingHandlerAdapter (org.springframework.web.servlet.mvc.method.annotation)
handleInternal:765, RequestMappingHandlerAdapter (org.springframework.web.servlet.mvc.method.annotation)
handle:85, AbstractHandlerMethodAdapter (org.springframework.web.servlet.mvc.method)
doDispatch:967, DispatcherServlet (org.springframework.web.servlet)
doService:901, DispatcherServlet (org.springframework.web.servlet)
processRequest:970, FrameworkServlet (org.springframework.web.servlet)
doGet:861, FrameworkServlet (org.springframework.web.servlet)
service:687, HttpServlet (javax.servlet.http)
service:846, FrameworkServlet (org.springframework.web.servlet)
service:790, HttpServlet (javax.servlet.http)
internalDoFilter:231, ApplicationFilterChain (org.apache.catalina.core)
doFilter:166, ApplicationFilterChain (org.apache.catalina.core)
doFilter:52, WsFilter (org.apache.tomcat.websocket.server)
internalDoFilter:193, ApplicationFilterChain (org.apache.catalina.core)
doFilter:166, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:99, RequestContextFilter (org.springframework.web.filter)
doFilter:107, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:193, ApplicationFilterChain (org.apache.catalina.core)
doFilter:166, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:109, HttpPutFormContentFilter (org.springframework.web.filter)
doFilter:107, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:193, ApplicationFilterChain (org.apache.catalina.core)
doFilter:166, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:93, HiddenHttpMethodFilter (org.springframework.web.filter)
doFilter:107, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:193, ApplicationFilterChain (org.apache.catalina.core)
doFilter:166, ApplicationFilterChain (org.apache.catalina.core)
doFilterInternal:197, CharacterEncodingFilter (org.springframework.web.filter)
doFilter:107, OncePerRequestFilter (org.springframework.web.filter)
internalDoFilter:193, ApplicationFilterChain (org.apache.catalina.core)
doFilter:166, ApplicationFilterChain (org.apache.catalina.core)
doFilter:43, IrisWebFilter (com.pdd.iris.spring.filter)
internalDoFilter:193, ApplicationFilterChain (org.apache.catalina.core)
doFilter:166, ApplicationFilterChain (org.apache.catalina.core)
invoke:199, StandardWrapperValve (org.apache.catalina.core)
invoke:96, StandardContextValve (org.apache.catalina.core)
invoke:493, AuthenticatorBase (org.apache.catalina.authenticator)
invoke:137, StandardHostValve (org.apache.catalina.core)
invoke:81, ErrorReportValve (org.apache.catalina.valves)
invoke:87, StandardEngineValve (org.apache.catalina.core)
service:343, CoyoteAdapter (org.apache.catalina.connector)
service:798, Http11Processor (org.apache.coyote.http11)
process:66, AbstractProcessorLight (org.apache.coyote)
process:808, AbstractProtocol$ConnectionHandler (org.apache.coyote)
doRun:1773, Nio2Endpoint$SocketProcessor (org.apache.tomcat.util.net)
run:49, SocketProcessorBase (org.apache.tomcat.util.net)
processSocket:1069, AbstractEndpoint (org.apache.tomcat.util.net)
completed:567, Nio2Endpoint$Nio2SocketWrapper$2 (org.apache.tomcat.util.net)
completed:545, Nio2Endpoint$Nio2SocketWrapper$2 (org.apache.tomcat.util.net)
invokeUnchecked:126, Invoker (sun.nio.ch)
run:218, Invoker$2 (sun.nio.ch)
run:112, AsynchronousChannelGroupImpl$1 (sun.nio.ch)
runWorker:1149, ThreadPoolExecutor (java.util.concurrent)
run:624, ThreadPoolExecutor$Worker (java.util.concurrent)
run:61, TaskThread$WrappingRunnable (org.apache.tomcat.util.threads)
run:748, Thread (java.lang)

为什么春天会这样做？这很难理解，我认为用户自定义逻辑具有更高的优先级，spring不应自动做出决定。

实际上，我认为问题有足够的解释，但SO认为主要是代码，要求添加更多细节，我该怎么办，在此先感谢。

Answer 1

这是一个很好的问题，但是对您来说最简单的解决方案可能是将produces参数用作映射注释：

@ResponseBody
@RequestMapping(value = "/live/timeshift.m3u8", method = RequestMethod.GET, produces = "application/vnd.apple.mpegurl")
public String playbackLive(@RequestParam(value = "delay") Integer delay) {
    ....
}

除非您需要动态分配响应的内容类型，否则我发现这种方式最简单。