解决httpclient上传multipart form-data文件失败

目标URL的multipart form-data是这样的

-----------------------------7e1a51350702Content-Disposition: form-data; name="keys"-----------------------------7e1a51350702Content-Disposition: form-data; name="typeid"1-----------------------------7e1a51350702Content-Disposition: form-data; name="BR_DESCRIPTION"-----------------------------7e1a51350702Content-Disposition: form-data; name="BR_EXPIREDATE"-----------------------------7e1a51350702Content-Disposition: form-data; name="BATCH_IMPORTFILE"; filename="xxx.txt"Content-Type: text/plain11111111111-----------------------------7e1a51350702Content-Disposition: form-data; name="BATCH_TYPE"0-----------------------------7e1a51350702--

然后原来的代码是这样的

            File uploadFile=new File(pre+"xxx.txt");            ContentType contentType=ContentType.create(ContentType.TEXT_PLAIN.getMimeType(), "GBK");            FileBody fileBody=new FileBody(uploadFile, contentType,"xxx.txt");            StringBody keys=new StringBody("",ContentType.MULTIPART_FORM_DATA);            StringBody typeid=new StringBody("3", ContentType.MULTIPART_FORM_DATA);            StringBody BR_DESCRIPTION=new StringBody("", ContentType.MULTIPART_FORM_DATA);            StringBody BR_EXPIREDATE=new StringBody("", ContentType.MULTIPART_FORM_DATA);            StringBody BATCH_TYPE=new StringBody("0", ContentType.MULTIPART_FORM_DATA);            HttpEntity httpEntity= MultipartEntityBuilder.create()                    .setLaxMode()                    .addPart("keys",keys)                    .addPart("typeid", typeid)                    .addPart("BR_DESCRIPTION", BR_DESCRIPTION)                    .addPart("BR_EXPIREDATE", BR_EXPIREDATE)                    .addPart("BATCH_IMPORTFILE", fileBody)                    .addPart("BATCH_TYPE", BATCH_TYPE)                    .build();            HttpPost doImportAdd=new HttpPost(importList);            doImportAdd.setEntity(httpEntity);            doImportAdd.addHeader("Accept", "application/x-ms-application, image/jpeg, application/xaml+xml, image/gif, image/pjpeg, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*");            doImportAdd.setHeader("Accept-Language", "zh-CN");            doImportAdd.setHeader("User-Agent", " Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/7.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET4.0C; .NET4.0E; MDDS; InfoPath.2)");            doImportAdd.setHeader("Content-Type", "multipart/form-data");            doImportAdd.setHeader("boundary", "---------------------------7e1103115079a");            doImportAdd.setHeader("Accept-Encoding", "gzip, deflate");            doImportAdd.setHeader("Connection", "Keep-Alive");

结果总是返回数据添加失败，但是返回的状态码是200，使用wireshark抓包，由于是使用程序执行的，所以选择本地连接，筛选出HTTP的请求
结果发现提示the multipart dissector could not find a required parameter

搜索该问题后在Stack Overflow 中找到有关的解决方法，就是把所有Header的构造都删除

删除后

 File uploadFile=new File(pre+"xxx.txt");            ContentType contentType=ContentType.create(ContentType.TEXT_PLAIN.getMimeType(), "GBK");            FileBody fileBody=new FileBody(uploadFile, contentType,"xxx.txt");            StringBody keys=new StringBody("",ContentType.MULTIPART_FORM_DATA);            StringBody typeid=new StringBody("3", ContentType.MULTIPART_FORM_DATA);            StringBody BR_DESCRIPTION=new StringBody("", ContentType.MULTIPART_FORM_DATA);            StringBody BR_EXPIREDATE=new StringBody("", ContentType.MULTIPART_FORM_DATA);            StringBody BATCH_TYPE=new StringBody("0", ContentType.MULTIPART_FORM_DATA);            HttpEntity httpEntity= MultipartEntityBuilder.create()                    .setLaxMode()                    .addPart("keys",keys)                    .addPart("typeid", typeid)                    .addPart("BR_DESCRIPTION", BR_DESCRIPTION)                    .addPart("BR_EXPIREDATE", BR_EXPIREDATE)                    .addPart("BATCH_IMPORTFILE", fileBody)                    .addPart("BATCH_TYPE", BATCH_TYPE)                    .build();            HttpPost doImportAdd=new HttpPost(importList);            doImportAdd.setEntity(httpEntity);

结果成功上传文本文件。

个人理解是因为在构建MultipartEntityBuilder是已经将模式设置为HttpMultipartMode.BROWSER_COMPATIBLE，在构建Header的话可能会产生冲突。只是个人见解，不知道是否正确。欢迎纠正。