在很多时候我们会遇到微服务之间文件传输，很多时候我们可以通过序列化等方式解决（如图片等）。

最近项目中有个excel上传，以及多媒体文件上传，直接报错。

也试了2种解决方式，都不可行。

1.     写一个文件Encoder解析器，会出现其他的rest请求出现encoder错误

2.     springcloud feign有一个规范，不可以传输2个对象，可以是一个对象带几个参数方式。

那么我们现在需要一种方式，不配置全局的解析器，而是通过Feign Builder 去管理上传文件，这种方式管理起来也较为方便。

引用包
<dependency>
    <groupId>com.netflix.feign</groupId>
    <artifactId>feign-core</artifactId>
    <version>8.17.0</version>
</dependency>
<dependency>
    <groupId>com.netflix.feign</groupId>
    <artifactId>feign-jackson</artifactId>
    <version>8.17.0</version>
</dependency>
<dependency>
    <groupId>com.netflix.feign</groupId>
    <artifactId>feign-slf4j</artifactId>
    <version>8.17.0</version>
</dependency>

调用方式

 

@ApiOperation(value = "上传Excel", notes = "上传Excel")
@RequestMapping(value = "/imExcel", method = RequestMethod.POST, produces = request_headers)
public ActionResult imExcel(@RequestBody MultipartFile file,@RequestParam("operatorId") Integer operatorId){

    if(file == null || file.isEmpty()|| operatorId==null)
        return new ActionResult<>(ResultType.BAD_REQUEST,"文件与操作用户ID都不能为空");
    String fileName = file.getOriginalFilename();
    if (!fileName.matches("^.+\\.(?i)(xls)$") && !fileName.matches("^.+\\.(?i)(xlsx)$")) {
        return new ActionResult<>(ResultType.BAD_REQUEST,"上传文件格式错误，请上传后缀为.xls或.xlsx的文件");
    }
    Feign.Builder encoder = Feign.builder()
            .decoder(new JacksonDecoder())
            .encoder(new FeignEncoder());
    FileUpload complainFileUpload = encoder.target(FileUpload.class,LABEL_URL);
    return complainFileUpload.imComplainExcel(file,operatorId);

}

 

文件Encode

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.CollectionUtils;
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;

/**
 * @author lxl
 */
public class FeignEncoder implements Encoder {


    private final List<HttpMessageConverter<?>> converters = new RestTemplate().getMessageConverters();
    private final HttpHeaders multipartHeaders = new HttpHeaders();
    private final HttpHeaders jsonHeaders = new HttpHeaders();

    public static final Charset UTF_8 = Charset.forName("UTF-8");

    public FeignEncoder() {
        multipartHeaders.setContentType(MediaType.MULTIPART_FORM_DATA);
        jsonHeaders.setContentType(MediaType.APPLICATION_JSON);
    }


    @Override
    public void encode(Object object, Type bodyType, RequestTemplate template) throws EncodeException {
        if (isFormRequest(bodyType)) {
            encodeMultipartFormRequest((Map<String, ?>) object, template);
        } else {
            encodeRequest(object, jsonHeaders, template);
        }
    }


    private void encodeMultipartFormRequest(Map<String, ?> formMap, RequestTemplate template) throws EncodeException {
        if (CollectionUtils.isEmpty(formMap)) {
            throw new EncodeException("参数不能为空.");
        }
        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());
    }

    /**
     * 设置头
     * @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);
        }
    }

    /**
     * 映射
     * @param map
     * @param name
     * @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);
        }
    }

    /**
     * {@link HttpEntity} {@code Content-type}
     * {@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);
    }

    /**
     * {@link org.springframework.web.client.RestTemplate}
     *
     * @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());
            }
        }
        /*
        使用bytearray方式传输
         */
        template.body(outputStream.toByteArray(), UTF_8);
    }

    /**
     * {@link org.springframework.http.HttpOutputMessage}
     * {@link org.springframework.http.converter.HttpMessageConverter}
     */
    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;
        }

    }


    static boolean isFormRequest(Type type) {
        return MAP_STRING_WILDCARD.equals(type);
    }


    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;
        }

    }

}

 

Feign调用接口

@RequestLine("POST /punish/imExcel")
ActionResult<List<String>> imPunishExcel(@Param("file") MultipartFile file, @Param("operatorId") Integer operatorId);