springboot如何接收text/plain参数
作者：不想码代码的程序员
这篇文章主要介绍了springboot如何接收text/plain参数的实现方式,具有很好的参考价值,希望对大家有所帮助,如有错误或未考虑完全的地方,望不吝赐教
springboot接收text/plain参数
Spring MVC在解析参数时
会通过
org.springframework.http.converter.HttpMessageConverter
转换器进行转换，转换器通过
org.springframework.http.converter.HttpMessageConverter#canRead
判断请求的MediaType + 不同实现的字段进行判断。
入口为
org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor#readWithMessageConverters
/** spring-webmvc-4.2.6 **/
/**
* Create the method argument value of the expected parameter type by reading
* from the given HttpInputMessage.
* @param <T> the expected type of the argument value to be created
* @param inputMessage the HTTP input message representing the current request
* @param param the method parameter descriptor (may be {@code null})
* @param targetType the target type, not necessarily the same as the method
* parameter type, e.g. for {@code HttpEntity<String>}.
* @return the created method argument value
* @throws IOException if the reading from the request fails
* @throws HttpMediaTypeNotSupportedException if no suitable message converter is found
*/
@SuppressWarnings("unchecked")
protected <T> Object readWithMessageConverters(HttpInputMessage inputMessage, MethodParameter param,
Type targetType) throws IOException, HttpMediaTypeNotSupportedException, HttpMessageNotReadableException {
MediaType contentType;
boolean noContentType = false;
try {
contentType = inputMessage.getHeaders().getContentType();
}
catch (InvalidMediaTypeException ex) {
throw new HttpMediaTypeNotSupportedException(ex.getMessage());
}
if (contentType == null) {
noContentType = true;
contentType = MediaType.APPLICATION_OCTET_STREAM;
}
Class<?> contextClass = (param != null ? param.getContainingClass() : null);
Class<T> targetClass = (targetType instanceof Class<?> ? (Class<T>) targetType : null);
if (targetClass == null) {
ResolvableType resolvableType = (param != null ?
ResolvableType.forMethodParameter(param) : ResolvableType.forType(targetType));
targetClass = (Class<T>) resolvableType.resolve();
}
HttpMethod httpMethod = ((HttpRequest) inputMessage).getMethod();
Object body = NO_VALUE;
try {
inputMessage = new EmptyBodyCheckingHttpInputMessage(inputMessage);
for (HttpMessageConverter<?> converter : this.messageConverters) {
Class<HttpMessageConverter<?>> converterType = (Class<HttpMessageConverter<?>>) converter.getClass();
if (converter instanceof GenericHttpMessageConverter) {
GenericHttpMessageConverter<?> genericConverter = (GenericHttpMessageConverter<?>) converter;
if (genericConverter.canRead(targetType, contextClass, contentType)) {
if (logger.isDebugEnabled()) {
logger.debug("Read [" + targetType + "] as \"" + contentType + "\" with [" + converter + "]");
}
if (inputMessage.getBody() != null) {
inputMessage = getAdvice().beforeBodyRead(inputMessage, param, targetType, converterType);
body = genericConverter.read(targetType, contextClass, inputMessage);
body = getAdvice().afterBodyRead(body, inputMessage, param, targetType, converterType);
}
else {
body = null;
body = getAdvice().handleEmptyBody(body, inputMessage, param, targetType, converterType);
}
break;
}
}
else if (targetClass != null) {
if (converter.canRead(targetClass, contentType)) {
if (logger.isDebugEnabled()) {
logger.debug("Read [" + targetType + "] as \"" + contentType + "\" with [" + converter + "]");
}
if (inputMessage.getBody() != null) {
inputMessage = getAdvice().beforeBodyRead(inputMessage, param, targetType, converterType);
body = ((HttpMessageConverter<T>) converter).read(targetClass, inputMessage);
body = getAdvice().afterBodyRead(body, inputMessage, param, targetType, converterType);
}
else {
body = null;
body = getAdvice().handleEmptyBody(body, inputMessage, param, targetType, converterType);
}
break;
}
}
}
}
catch (IOException ex) {
throw new HttpMessageNotReadableException("Could not read document: " + ex.getMessage(), ex);
}
if (body == NO_VALUE) {
if (httpMethod == null || !SUPPORTED_METHODS.contains(httpMethod) ||
(noContentType && inputMessage.getBody() == null)) {
return null;
}
throw new HttpMediaTypeNotSupportedException(contentType, this.allSupportedMediaTypes);
}
return body;
}
通过
org.springframework.http.converter.HttpMessageConverter#canRead
判断当前转换器是否支持当前请求。
当MediaType为text/plain时
支持的转换器为
org.springframework.http.converter.StringHttpMessageConverter
该转换器只支持String 对象的转换，所以当content-type为text/plain时，接收参数应为String，且需要添加@RequestBody注解。
具体代码如下：
public class TestController {
@RequestMapping(consume = Media.TEXT_PLAIN_VALUE)
public void textPalinRequest(@RequestBody String requestBody){
}
}总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。