遇到的问题

在使用Spring REST时，有一个需要返回xml格式数据的方法：

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@PostMapping(value = "/payment", consumes = {MediaType.TEXT_XML_VALUE}, produces = {MediaType.ALL_VALUE})
public Map<String, String> wxPayCallback(@RequestBody Map<String, String> paraMap) throws Exception {
}

被调用时”org.springframework.web.HttpMediaTypeNotSupportedException: Content type ‘text/xml;charset=UTF-8′ not supported”异常。

[http-nio-8085-exec-7] ERROR c.s.m.r.e.ControllerExceptionHandler - 异常：415
org.springframework.web.HttpMediaTypeNotSupportedException: Content type 'text/xml;charset=UTF-8' not supported
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:226)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.readWithMessageConverters(RequestResponseBodyMethodProcessor.java:157)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:130)
    at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:124)
    at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:161)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:131)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:870)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:776)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:881)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)

原因和解决办法

乍一看似乎是consumes指定的content-type不对导致，实际上是缺少依赖导致，spring rest默认只包含json格式的转换，不包含xml格式的转换，因此pom内增加依赖来解决。

<dependency>
   <groupId>com.fasterxml.jackson.dataformat</groupId>
   <artifactId>jackson-dataformat-xml</artifactId>
</dependency>

增加上述依赖后，上面的方法会正常访问，但如果RestController上没有指明produces，增加上述依赖后，会默认输出xml，而不再是json。
可以通过

@Configuration
public class WebAppConfigurer extends WebMvcConfigurationSupport {
 
    @Override
    protected void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
        configurer.defaultContentType(MediaType.APPLICATION_JSON);
    }
     
}

来修改默认的produces。