調用Spring（4.x）Rest服務

即使我看到很多關於這個問題的問題，但沒有人對我有用。我正在嘗試發佈一個簡單的REST服務，但並不重要，我做的，它不工作。調用Spring（4.x）Rest服務

我的第一個方法是創建一個REST控制器是這樣的：

@RestController 
public class ProductsRestController { 

    @Autowired 
    private ProductService productService; 

    @Transactional 
    @RequestMapping(value = "/listproducts") 
    public List<Product> products() { 
     return this.productService.findAll(); 
    } 
}

當調用它（通過瀏覽器）一個HttpMediaTypeNotAcceptableException被拋出

谷歌搜索我達到了這個Question。提出的解決方案是配置一個MappingJacksonHttpMessageConverter並將其添加到AnnotationMethodHandlerAdapter。由於這些豆類在春天4.x的過時，我用RequestMappingHandlerAdapter與MappingJackson2HttpMessageConverter這樣（我WebMvcConfigurerAdapter內）：

這conduced我以下錯誤：

java.lang.ClassNotFoundException: com.fasterxml.jackson.core.JsonProcessingException

我增加了所需的依賴

<artifactId>jackson-core</artifactId> 
<artifactId>jackson-databind</artifactId>

和結果上：

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalStateException: getOutputStream() has already been called for this response 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978) 
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:621) 
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728) 
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88) 
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) 
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) 
    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$VirtualFilterChain.doFilter(FilterChainProxy.java:342) 
    org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:199) 
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) 
    org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:110) 
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) 
    org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:85) 
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) 
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342) 
    org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:57) 
    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.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.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192) 
    org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160) 
    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344) 
    org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)

再次使用谷歌搜索我到達了這個其他Question但這一個都沒有用。

有沒有人知道底層的問題是什麼？

在此先感謝！此致敬禮。

來源

2015-01-14 Emiliano Schiano

將適當的傑克遜版本添加到您的類路徑中，添加'@ EnableWebMvc'並將剩下的部分留給Spring。您不需要添加'HandleAdapter'或自定義的'HttpMessageConverter'。 –

你說得對。看來只是addind jackson deps，Spring自動配置處理程序。儘管如此，仍然發生了同樣的錯誤（getOutputStream（）已被調用）。 –

您是否配置了自定義過濾器來讀取請求/響應？ –

無論問題是什麼，總會有更多的事情要做。這個其他Question幫助解決了我的問題。

事情是產品類有引用到其他bean的引用再次，所以循環引用正在發生。使用DTO解決了這個問題。

感謝大家的支持。

來源

2015-01-14 14:26:31

調用Spring（4.x）Rest服務

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