1. 新增编码器(由于使用了动态的Feign,所以不能像正常使用Feign一样指定configuration配置编码器)
import feign.RequestTemplate; import feign.codec.EncodeException; import feign.codec.Encoder; import org.springframework.core.io.InputStreamResource; import org.springframework.core.io.Resource; import org.springframework.http.HttpEntity; import org.springframework.http.HttpHeaders; import org.springframework.http.HttpOutputMessage; import org.springframework.http.MediaType; import org.springframework.http.converter.HttpMessageConverter; import org.springframework.util.LinkedMultiValueMap; import org.springframework.web.client.RestTemplate; import org.springframework.web.multipart.MultipartFile; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.lang.reflect.Type; import java.nio.charset.Charset; import java.util.Arrays; import java.util.List; import java.util.Map; import java.util.Map.Entry; /** * A custom {@link Encoder} that supports Multipart requests. It uses * {@link HttpMessageConverter}s like {@link RestTemplate} does. * * @author Pierantonio Cangianiello */ public class FeignSpringFormEncoder implements Encoder { private final List<HttpMessageConverter<?>> converters = new RestTemplate().getMessageConverters(); public static final Charset UTF_8 = Charset.forName("UTF-8"); public FeignSpringFormEncoder() { } /** * {@inheritDoc } */ @Override public void encode(Object object, Type bodyType, RequestTemplate template) throws EncodeException { if (isFormRequest(bodyType)) { final HttpHeaders multipartHeaders = new HttpHeaders(); multipartHeaders.setContentType(MediaType.MULTIPART_FORM_DATA); encodeMultipartFormRequest((Map<String, ?>) object, multipartHeaders, template); } else { final HttpHeaders jsonHeaders = new HttpHeaders(); jsonHeaders.setContentType(MediaType.APPLICATION_JSON); encodeRequest(object, jsonHeaders, template); } } /** * Encodes the request as a multipart form. It can detect a single {@link MultipartFile}, an * array of {@link MultipartFile}s, or POJOs (that are converted to JSON). * * @param formMap * @param template * @throws EncodeException */ private void encodeMultipartFormRequest(Map<String, ?> formMap, HttpHeaders multipartHeaders, RequestTemplate template) throws EncodeException { if (formMap == null) { throw new EncodeException("Cannot encode request with null form."); } LinkedMultiValueMap<String, Object> map = new LinkedMultiValueMap<>(); for (Entry<String, ?> entry : formMap.entrySet()) { Object value = entry.getValue(); if (isMultipartFile(value)) { map.add(entry.getKey(), encodeMultipartFile((MultipartFile) value)); } else if (isMultipartFileArray(value)) { encodeMultipartFiles(map, entry.getKey(), Arrays.asList((MultipartFile[]) value)); } else { map.add(entry.getKey(), encodeJsonObject(value)); } } encodeRequest(map, multipartHeaders, template); } private boolean isMultipartFile(Object object) { return object instanceof MultipartFile; } private boolean isMultipartFileArray(Object o) { return o != null && o.getClass().isArray() && MultipartFile.class.isAssignableFrom(o.getClass().getComponentType()); } /** * Wraps a single {@link MultipartFile} into a {@link HttpEntity} and sets the * {@code Content-type} header to {@code application/octet-stream} * * @param file * @return */ private HttpEntity<?> encodeMultipartFile(MultipartFile file) { HttpHeaders filePartHeaders = new HttpHeaders(); filePartHeaders.setContentType(MediaType.APPLICATION_OCTET_STREAM); try { Resource multipartFileResource = new MultipartFileResource(file.getOriginalFilename(), file.getSize(), file.getInputStream()); return new HttpEntity<>(multipartFileResource, filePartHeaders); } catch (IOException ex) { throw new EncodeException("Cannot encode request.", ex); } } /** * Fills the request map with {@link HttpEntity}s containing the given {@link MultipartFile}s. * Sets the {@code Content-type} header to {@code application/octet-stream} for each file. * * @param map current request map. * @param name the name of the array field in the multipart form. * @param files */ private void encodeMultipartFiles(LinkedMultiValueMap<String, Object> map, String name, List<? extends MultipartFile> files) { HttpHeaders filePartHeaders = new HttpHeaders(); filePartHeaders.setContentType(MediaType.APPLICATION_OCTET_STREAM); try { for (MultipartFile file : files) { Resource multipartFileResource = new MultipartFileResource(file.getOriginalFilename(), file.getSize(), file.getInputStream()); map.add(name, new HttpEntity<>(multipartFileResource, filePartHeaders)); } } catch (IOException ex) { throw new EncodeException("Cannot encode request.", ex); } } /** * Wraps an object into a {@link HttpEntity} and sets the {@code Content-type} header to * {@code application/json} * * @param o * @return */ private HttpEntity<?> encodeJsonObject(Object o) { HttpHeaders jsonPartHeaders = new HttpHeaders(); jsonPartHeaders.setContentType(MediaType.APPLICATION_JSON); return new HttpEntity<>(o, jsonPartHeaders); } /** * Calls the conversion chain actually used by * {@link RestTemplate}, filling the body of the request * template. * * @param value * @param requestHeaders * @param template * @throws EncodeException */ private void encodeRequest(Object value, HttpHeaders requestHeaders, RequestTemplate template) throws EncodeException { ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); HttpOutputMessage dummyRequest = new HttpOutputMessageImpl(outputStream, requestHeaders); try { Class<?> requestType = value.getClass(); MediaType requestContentType = requestHeaders.getContentType(); for (HttpMessageConverter<?> messageConverter : converters) { if (messageConverter.canWrite(requestType, requestContentType)) { ((HttpMessageConverter<Object>) messageConverter).write( value, requestContentType, dummyRequest); break; } } } catch (IOException ex) { throw new EncodeException("Cannot encode request.", ex); } HttpHeaders headers = dummyRequest.getHeaders(); if (headers != null) { for (Entry<String, List<String>> entry : headers.entrySet()) { template.header(entry.getKey(), entry.getValue()); } } /* we should use a template output stream... this will cause issues if files are too big, since the whole request will be in memory. */ template.body(outputStream.toByteArray(), UTF_8); } /** * Minimal implementation of {@link HttpOutputMessage}. It's needed to * provide the request body output stream to * {@link HttpMessageConverter}s */ private class HttpOutputMessageImpl implements HttpOutputMessage { private final OutputStream body; private final HttpHeaders headers; public HttpOutputMessageImpl(OutputStream body, HttpHeaders headers) { this.body = body; this.headers = headers; } @Override public OutputStream getBody() throws IOException { return body; } @Override public HttpHeaders getHeaders() { return headers; } } /** * Heuristic check for multipart requests. * * @param type * @return * @see feign.Types */ static boolean isFormRequest(Type type) { return MAP_STRING_WILDCARD.equals(type); } /** * Dummy resource class. Wraps file content and its original name. */ static class MultipartFileResource extends InputStreamResource { private final String filename; private final long size; public MultipartFileResource(String filename, long size, InputStream inputStream) { super(inputStream); this.size = size; this.filename = filename; } @Override public String getFilename() { return this.filename; } @Override public InputStream getInputStream() throws IOException, IllegalStateException { return super.getInputStream(); //To change body of generated methods, choose Tools | Templates. } @Override public long contentLength() throws IOException { return size; } } }
2. 配置文件中配置编码器
feign.client.config.default.encoder=完整包名.FeignSpringFormEncoder
3. 新增FeignClientUtil类
import org.springframework.beans.BeansException; import org.springframework.cloud.openfeign.FeignClientBuilder; import org.springframework.context.ApplicationContext; import org.springframework.context.ApplicationContextAware; import org.springframework.stereotype.Component; import java.util.Map; import java.util.Objects; import java.util.concurrent.ConcurrentHashMap; @Component public class FeignClientUtils implements ApplicationContextAware { private static ApplicationContext applicationContext = null; private static final Map<String, Object> BEAN_CACHE = new ConcurrentHashMap<>(); @Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { if (FeignClientUtils.applicationContext == null) { FeignClientUtils.applicationContext = applicationContext; } } public static <T> T build(String serverName, Class<T> targetClass) { return buildClient(serverName, targetClass); } @SuppressWarnings("unchecked") private static <T> T buildClient(String serverName, Class<T> targetClass) { T t = (T) BEAN_CACHE.get(serverName); if (Objects.isNull(t)) { FeignClientBuilder.Builder<T> builder = new FeignClientBuilder(applicationContext).forType(targetClass, serverName); t = builder.build(); BEAN_CACHE.put(serverName, t); } return t; } }
4. 新增interface
import xxx.ApiResult; import org.springframework.web.bind.annotation.*; import java.util.Map; public interface IFeignClientTemplate { @GetMapping(value = "/{url}", headers = {"Content-Type: application/json"}) ApiResult get(@PathVariable("url") String url, @RequestParam Map<String, Object> params); @PostMapping(value = "/{url}", headers = {"Content-Type: application/json"}, consumes = "application/json") ApiResult post(@PathVariable("url") String url, Map<String, Object> params); @PostMapping(value = "/{url}") ApiResult postFile(@PathVariable("url") String url, Map<String, ?> params); }
5. 使用实例
String serviceName = "xxx"; // 注册在nacos的服务名称 String url = "xxx"; // 请求的url的接口 DynamicFeignClient client = FeignClientUtils.build(serviceName, DynamicFeignClient.class); ApiResult result = client.get(url,new HashMap<>());
PS:过程中遇到了一些问题,也使用了RequestLine注解,最后都调整与解决了,编码器是必要的,不然无法转换为指定的DTO
如果有人知道怎么在这种情况下使用Configuration配置编码解码注解,也请不吝赐教(试了几个都不行,在build client中指定也不行,没有对应方法)
target values must be absolute. java.lang.IllegalStateException: Method has too many Body parameters: public abstract java.lang.String xxx.IFeignClientTemplate.get(java.lang.String,java.lang.Object) feign.FeignException$NotFound: status 404 reading IFeignClientTemplate#get(String) status 405 reading IFeignClientTemplate#get(String,HashMap) No serializer found for class java.io.FileDescriptor and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) 等报错
标签:Feign,java,import,接口,public,private,new,服务器,HttpHeaders From: https://www.cnblogs.com/uoky/p/18302515