遇到一个问题,我们的服务只做代理功能,有时候需要转发文件,又不能把文件先保存下来后再读取文件上传到第三方服务器,这时候就要直接发送流文件。
restTemplate(亲测有效,很费劲才找到的):
class MultipartInputStreamFileResource extends InputStreamResource {
private final String filename;
MultipartInputStreamFileResource(InputStream inputStream, String filename) {
super(inputStream);
this.filename = filename;
}
@Override
public String getFilename() {
return this.filename;
}
@Override
public long contentLength() throws IOException {
return -1; // we do not want to generally read the whole stream into memory ...
}
}
LinkedMultiValueMap<String, Object> map = new LinkedMultiValueMap<>();
try {
if (!file.isEmpty()) {
map.add("images", new MultipartInputStreamFileResource(file.getInputStream(), file.getOriginalFilename()));
}
}
HttpClient(亲测有效,但可以能与restTemplate某些地方冲突,因为RestTemplate底层实现是有多种的,
引入HttpClient包之后会用新的实现,导致原先RestTemplate发的请求都不会重写Host了,这个坑至今详细原因不明,
所以项目中还是用统一的Http Client吧)
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpResponse response = null;
String result = "";
try {
String fileName = multipartFile.getOriginalFilename();
HttpPost httpPost = new HttpPost(url);
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.addBinaryBody("file", multipartFile.getInputStream(), ContentType.MULTIPART_FORM_DATA, fileName);
if (cuser == null) {
cuser = "0";
}
builder.addTextBody("cuser", cuser);
org.apache.http.HttpEntity entity = builder.build();
httpPost.setEntity(entity);
response = httpClient.execute(httpPost);
result = EntityUtils.toString(response.getEntity(), Charset.forName("UTF-8"));
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}