使用Feign实现微服务间文件传输
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);
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