在项目微服务的升级过程中，我们通常会设置一个网关，作为一个洪流的出入口，在Spring Cloud 中提供了对应的功能，也就是Spring Cloud Gateway。对于旧的项目springMVC，实际也就是将spring-webmvc升级为spring-webflux，但你会发现fromdata 形式的数据，在webmvc可以被封装成参数，而在webflux中却不能，是不支持吗？
在spring官方文档中，有提及对fromdata表单数据的获取，如下图

fromdata表单数据需要通过ServerWebExchange 的getFormData()获取【也可以通过getMultipartData（）方法获取数据】
主要对数据处理的代码如下：

//exchange 为 ServerWebExchange 
exchange.getMultipartData().map(data ->{Map<String, Part> stringPartMap = data.toSingleValueMap();//表单参数名Part name= stringPartMap.get("name");//将name进行处理转换处理转换代码//返回处理后的值return name;});

具体的例子：比如需要从表单中取出file（MultipartFile）

@PostMapping("/api/test2")
public Object test2(ServerWebExchange exchange){return exchange.getMultipartData().map(data ->{Map<String, Part> stringPartMap = data.toSingleValueMap();Part file = stringPartMap.get("file");if(file instanceof FilePart){File file1 = null;try {FilePart filePart = (FilePart)file;file1 = new File(filePart.filename());filePart.transferTo(file1);//获取到MultipartFile MultipartFile multipartFile = FileUtil.fileToMultipartFile(file1);//业务代码块} catch (Exception e) {throw new RuntimeException("参数分析错误!");}finally {if(file1.exists()){file1.delete();}}}return "success";});}

文件处理工具类

public class FileUtil {public static MultipartFile fileToMultipartFile(File file) {FileItem fileItem = createFileItem(file);return new CommonsMultipartFile(fileItem);}public static FileInputStream fileToFileInputStream(File file) {FileInputStream fileInputStream = null;try {fileInputStream = new FileInputStream(file);} catch (FileNotFoundException e) {e.printStackTrace();}return fileInputStream;}public static File filePartToFile(FilePart filePart,File file) {file = new File(filePart.filename());filePart.transferTo(file);return file;}private static FileItem createFileItem(File file) {FileItemFactory factory = new DiskFileItemFactory(16, null);FileItem item = factory.createItem("textField", "text/plain", true, file.getName());int bytesRead;byte[] buffer = new byte[8192];try {FileInputStream fis = new FileInputStream(file);OutputStream os = item.getOutputStream();while ((bytesRead = fis.read(buffer, 0, 8192)) != -1) {os.write(buffer, 0, bytesRead);}os.close();fis.close();} catch (IOException e) {e.printStackTrace();}return item;}
}

直此，我们就能够获取到fromdata的数据

但这样子对于想获取fromdata数据，每次都需要引用ServerWebExchange ，然后通过getMultipartData（）方法获取数据，比较臃肿，能否对数据重新进行封装呢，答案是可以的，下面我通过注解和配置封装参数解析类 进行fromdata数据的二次封装，代码案例如下：
controller层代码：

 @PostMapping("/api/test2")public String test2(@ParameterConversion(name = "file",type = MultipartFile.class) MultipartFile multipartFile,@ParameterConversion(name = "name",type = String.class) String name,@ParameterConversion(name = "id",type = Integer.class) Integer id){//业务代码块return "success";}

注解类

@Inherited
@Documented
@Target({ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
public @interface ParameterConversion {//解析的名称String name();//转化的类型Class<?> type();
}

WebConfigurer 配置类

@Configuration
public class WebConfigurer implements WebFluxConfigurer {/*** 加入自定义方法参数解析器* @param configurer*/@Overridepublic void configureArgumentResolvers(ArgumentResolverConfigurer configurer) {List<HttpMessageReader<?>> readers=new ArrayList<>();//添加Http消息编解码器readers.add(new DecoderHttpMessageReader<>(new Jackson2JsonDecoder()));//消息编解码器与Resolver绑定configurer.addCustomResolver(new ParamsResolver(readers));}}

请求参数二次解析封装

public class ParamsResolver extends AbstractMessageReaderArgumentResolver {public ParamsResolver(List<HttpMessageReader<?>> readers) {super(readers);}protected ParamsResolver(List<HttpMessageReader<?>> messageReaders, ReactiveAdapterRegistry adapterRegistry) {super(messageReaders, adapterRegistry);}/*** 判断是否需要解析参数* @param methodParameter* @return*/@Overridepublic boolean supportsParameter(MethodParameter methodParameter) {System.out.println("into supportsParameter");if (!methodParameter.hasParameterAnnotation(ParameterConversion.class)) {return false;} else {ParameterConversion parameterAnnotation= methodParameter.getParameterAnnotation(ParameterConversion.class);return parameterAnnotation != null && methodParameter.getParameterType().isAssignableFrom(parameterAnnotation.type())&& Objects.nonNull(parameterAnnotation.name());}}@Overridepublic Mono<Object> resolveArgument(MethodParameter methodParameter, BindingContext bindingContext, ServerWebExchange serverWebExchange) {System.out.println("into resolveArgument");ParameterConversion parameterAnnotation= methodParameter.getParameterAnnotation(ParameterConversion.class);String name = parameterAnnotation.name();Class<?> type = parameterAnnotation.type();return serverWebExchange.getMultipartData().map(data -> {Part part = data.toSingleValueMap().get(name);if (part == null)throw new RuntimeException("ParameterConversion fail");Object partObj = partToClass(part, type);Assert.notNull(partObj,"ParameterConversion fail, 不支持该类型转换");return partObj;});}private Object partToClass(Part part,Class<?> type){if (type == MultipartFile.class && part instanceof FilePart) {File file = null;try {FilePart filePart = (FilePart) part;file = new File(filePart.filename());filePart.transferTo(file);return FileUtil.fileToMultipartFile(file);} finally {if (file != null && file.exists()) {file.delete();}}} else if (type == FilePart.class) {return part;}else if (type == String.class){return bufferToStr(part.content());} else if (type == Integer.class) {return Integer.parseInt(bufferToStr(part.content()));} else if (type == BigDecimal.class) {return new BigDecimal(bufferToStr(part.content()));} else {return null;}}private String bufferToStr(Flux<DataBuffer> content){AtomicReference<String> res = new AtomicReference<>();content.subscribe(buffer -> {byte[] bytes = new byte[buffer.readableByteCount()];buffer.read(bytes);DataBufferUtils.release(buffer);res.set(new String(bytes, StandardCharsets.UTF_8));});return res.get();}
}

以上代码，为作者个人观点，如有不足处，请指教；