HTTP Status 500 - ... IllegalArgumentException: Unknown return value type when I use ResponseStatus annotation and return value in spring controller答案

【问题标题】：HTTP Status 500 - ... IllegalArgumentException: Unknown return value type when I use ResponseStatus annotation and return value in spring controllerHTTP Status 500 - ... IllegalArgumentException: Unknown return value type when I use ResponseStatus annotation and return value in spring controller
【发布时间】：2015-01-26 14:16:10
【问题描述】：

我写了以下控制器方法：

    @RequestMapping(value = "/member/createCompany/uploadImage1", method = RequestMethod.GET)
    @ResponseStatus(HttpStatus.OK)
    public Long handle() {
        return 1l;
    }

当我在浏览器中请求此方法时，我看到以下内容：

HTTP Status 500 - Request processing failed; nested exception is java.lang.IllegalArgumentException: Unknown return value type [java.lang.Long]

type Exception report

message Request processing failed; nested exception is java.lang.IllegalArgumentException: Unknown return value type [java.lang.Long]

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalArgumentException: Unknown return value type [java.lang.Long]
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:948)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
    org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:154)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:50)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
    org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:343)
    org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:260)
root cause

java.lang.IllegalArgumentException: Unknown return value type [java.lang.Long]
    org.springframework.util.Assert.notNull(Assert.java:112)
    org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:68)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:122)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:745)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:686)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(Charac
    .........

是我实现服务器端错误还是客户端问题？

更新到 njjnex 答案。

如果我想在控制器方法中实现以下逻辑应该怎么做：

       if(someCondition){
           return 1l;
       }else{
         //I want to return 500 or 400 http code
       }

【问题讨论】：

听起来像是您返回的 long 应用程序期望某些可能是字符串的视图类型。真的是这样吗？您是否有其他可以粘贴的具有相同类型（或类似）结构的控制器？
在调试中我看到移动到控制器方法

标签： java javascript web-services rest spring-mvc

【解决方案1】：

在这种情况下使用@ResponseBody 注释。如果没有它，Spring 会将您的返回值解释为视图名称。但它不能太长，这就是为什么你得到错误Unknown return value type

@ResponseBody 注解类似于@RequestBody。这注释可以放在方法上并指示返回类型应直接写入 HTTP 响应正文（而不是放置在模型中，或解释为视图名称）。

Spring Reference ResponseBody

如果您想从 ResponseBody 中返回错误代码，请使用：

return new ResponseEntity<String>(HttpStatus.BAD_REQUEST);

另见How to respond HTTP error in a @ResponseBody

【讨论】：

【解决方案2】：

@RestController 是控制器的特殊版本。它包含 @Controller 和 @ResponseBody 注释，因此简化了控制器的实现：

@RestController
@RequestMapping("books-rest")
public class SimpleBookRestController {

@GetMapping("/{id}", produces = "application/json")
public Book getBook(@PathVariable int id) {
    return findBookById(id);
}

private Book findBookById(int id) {
    // ...
}


 }

我认为是这种情况（未知的返回值类型）。我认为您在此类中应用了@Controller 注释。如果你想修复它，你需要申请@Controller 而不是@RestController annotatan。

请参考此链接，
https://www.baeldung.com/spring-controller-vs-restcontroller

【讨论】：