spring接口通过配置支持返回多种格式（xml,json,html,excel）

 curl --header 'Accept:application/json' http://localhost:8080/todo

 curl -X PUT --header 'Content-Type:application/json' -d '{"title":"周末日程","content":"睡觉"}' http://localhost:8080/todo

@Override
public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
 configurer.favorPathExtension(false)
   .favorParameter(true)
   .parameterName("mediaType")
   .defaultContentType(MediaType.APPLICATION_JSON)
   .mediaType("xml", MediaType.APPLICATION_XML)
   .mediaType("html", MediaType.TEXT_HTML)
   .mediaType("json", MediaType.APPLICATION_JSON);
}

ByteArrayHttpMessageConverter – converts byte arrays
StringHttpMessageConverter – converts Strings
ResourceHttpMessageConverter – converts org.springframework.core.io.Resource for any type of octet stream
SourceHttpMessageConverter – converts javax.xml.transform.Source
FormHttpMessageConverter – converts form data to/from a MultiValueMap<String, String>.
Jaxb2RootElementHttpMessageConverter – converts Java objects to/from XML (added only if JAXB2 is present on the classpath)
MappingJackson2HttpMessageConverter – converts JSON (added only if Jackson 2 is present on the classpath)
MappingJacksonHttpMessageConverter – converts JSON (added only if Jackson is present on the classpath)
AtomFeedHttpMessageConverter – converts Atom feeds (added only if Rome is present on the classpath)
RssChannelHttpMessageConverter – converts RSS feeds (added only if Rome is present on the classpath)

compile group: 'org.springframework', name: 'spring-oxm', version: '4.3.9.RELEASE'
compile group: 'com.thoughtworks.xstream', name: 'xstream', version: '1.4.10'

@Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
 converters.add(createXmlHttpMessageConverter());
 super.configureMessageConverters(converters);
}
private HttpMessageConverter<Object> createXmlHttpMessageConverter() {
 MarshallingHttpMessageConverter xmlConverter =
   new MarshallingHttpMessageConverter();
 XStreamMarshaller xstreamMarshaller = new XStreamMarshaller();
 xmlConverter.setMarshaller(xstreamMarshaller);
 xmlConverter.setUnmarshaller(xstreamMarshaller);
 return xmlConverter;
}

compile("org.springframework.boot:spring-boot-starter-freemarker")