遇到一种业务场景，前端上传的文件需要经过java服务转发至文件服务。期间遇到了原生HttpClient怎么使用的问题、怎么把MultipartFile怎么重新组装成Http请求发送出去的问题、文件中文名乱码问题。最后都解决了，先上代码，再讲遇到的坑
1 @Slf4j
2 @Service
3 public class FileServiceImpl implements IFileService {
4
5 @Value("${FileService.putUrl}")
6 private String putUrl;
7 @Value("${FileService.app_id}")
8 private String appId;
9 @Value("${FileService.securityKey}")
10 private String secureKey;
11
12 private final static String UPLOAD_RESPONSE_CODE = "error";
13 private final static Integer UPLOAD_RESPONSE_SUCCESS = 0;
14
15
16 @Override
17 public String upload(MultipartFile file) {
18
19 int timeOut = 30000;
20 CloseableHttpClient httpClient = HttpClientBuilder.create().build();
21 HttpHost proxy = new HttpHost("127.0.0.1", 62145, "http"); //设置本地fiddler代理，方便排查问题
22 RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(timeOut)
23 .setConnectTimeout(timeOut).setSocketTimeout(timeOut).setProxy(proxy).build();
24 HttpPost httpPost = new HttpPost(putUrl);
25 httpPost.setConfig(requestConfig);
26 try {
27 //BROWSER_COMPATIBLE自定义charset，RFC6532=utf-8，STRICT=iso-8859-1
28 //此处一定要用RFC6532，网上普遍用的BROWSER_COMPATIBLE依然会出现中文名乱码
29 MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create().setMode(HttpMultipartMode.RFC6532);
30 //multipartEntityBuilder.setCharset(Charset.forName("UTF-8")); //此处踩坑，转发出去的filename依然为乱码
31 //ContentType contentType = ContentType.create("multipart/form-data",Charset.forName("UTF-8")); //此处也是坑，转发出去的filename依然为乱码
32 multipartEntityBuilder.addBinaryBody("file", file.getInputStream(), ContentType.DEFAULT_BINARY, file.getOriginalFilename());
33
34 multipartEntityBuilder.addTextBody("app_id", appId); //可替换成你自己需要的附加字段
35 long time = System.currentTimeMillis() / 1000;
36 multipartEntityBuilder.addTextBody("time", String.valueOf(time)); //可替换成你自己需要的附加字段
37 String beforeSign = String.format("app_id=%s&time=%s%s", appId, time, secureKey);
38 String sign = MD5Util.md5(beforeSign);
39 multipartEntityBuilder.addTextBody("sign", sign); //可替换成你自己需要的附加字段
40
41 HttpEntity requestEntity = multipartEntityBuilder.build();
42 httpPost.setEntity(requestEntity);
43 HttpResponse httpResponse = httpClient.execute(httpPost);
44 int statusCode= httpResponse.getStatusLine().getStatusCode();
45 if (statusCode != 200) throw new BizException(BizCode.INNER_SERVICE_ERROR, "响应状态码为：" + statusCode);
46 HttpEntity responseEntity = httpResponse.getEntity();
47 return getUrlString(EntityUtils.toString(responseEntity));
48 } catch (Exception e) {
49 log.error("发送文件异常：{}", e);
50 throw new BizException(BizCode.INNER_SERVICE_ERROR, "发送文件服务异常:" + e.getMessage());
51 } finally {
52 try {
53 httpClient.close();
54 } catch (IOException e) {
55 log.error("关闭httpClient异常：" + e.getMessage(), e);
56 }
57 }
58 }
59
60 private String getUrlString(String jsonString) {
61 try{
62 log.debug("解析json串："+ jsonString);
63 JSONObject jsonObject = JSONObject.parseObject(jsonString);
64 if (jsonObject.getInteger(UPLOAD_RESPONSE_CODE) != UPLOAD_RESPONSE_SUCCESS) {
65 log.error("文件服务返回错误：" + jsonObject.getString("data"));
66 throw new OtherServiceReturnErrorException("文件服务返回错误：" + jsonObject.getString("data"));
67 }
68 return ((JSONObject)jsonObject.get("data")).get("original").toString();
69 }catch (Exception e) {
70 log.error("文件服务返回json解析错误：" + jsonString);
71 throw new OtherServiceReturnErrorException("文件服务返回json解析错误：" + jsonString);
72 }
73
74 }
75 }
特别说明及遇到的坑：
1. 这里基于tomcat进行请求转发，需要在代码中手动添加代理：
HttpHost proxy = new HttpHost("127.0.0.1", 62145, "http"); //设置本地fiddler代理，方便排查问题RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(timeOut) .setConnectTimeout(timeOut).setSocketTimeout(timeOut).setProxy(proxy).build();
2. MultipartFile通过getInputStream()可以将流设置到MultipartEntityBuilder中，其中addBinaryBody里面的ContentType 和 filename必须设置，要不然后续服务读取不到这个文件流
MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create().setMode(HttpMultipartMode.RFC6532);
multipartEntityBuilder.addBinaryBody("file", file.getInputStream(), ContentType.DEFAULT_BINARY, file.getOriginalFilename());
3. file.getOriginalFilename()方法虽然没有乱码，但是addBinaryBody后，组装的Http请求出去总是乱码，如下图：
踩了各种坑，如为MultipartEntityBuilder设置Charset或者是手动设置ContentType，都无法解决此问题，文件名依然是上图所示乱码
后来发现在MultipartEntityBuilder中设置Mode为HttpMultipartMode.RFC6532可以完美解决这个问题，并且不再需要单独设置ContentType或Charset，因为HttpMultipartMode.RFC6532就告诉了MultipartEntityBuilder，里面的数据都要使用UTF-8进行处理，fiddler抓到的请求发现filename成功变成中文名。
done
原文地址：https://www.cnblogs.com/evasean/p/9368670.html