Docusignapi Apache Http 4.5 StringBody构造函数未在请求中导出内容类型

使用Apache Http 4.5 MultipartEntityBuilder，似乎无法理解为什么StringBody（String，ContentType）构造函数实际上没有在请求表单正文中输出内容类型

public HttpRequestBase build() throws UnsupportedEncodingException {
    HttpPost httpPost = new HttpPost("https://{server}/restapi/{apiVersion}/accounts/{accountId}/envelopes");

    MultipartEntityBuilder builder = MultipartEntityBuilder.create();
    builder.setContentType(ContentType.MULTIPART_FORM_DATA);
    builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
    builder.setBoundary("AAA");

    //add form body
    builder.addPart(generateJsonFormBodyPart());

    //add file body
    builder.addPart(generateFileFormBodyPart()); //<--intentionally omitted

    HttpEntity multipart = builder.build();

    httpPost.setEntity(multipart);

    return httpPost;

}

private FormBodyPart generateJsonFormBodyPart() throws UnsupportedEncodingException{
        StringBody json = new StringBody(packageJson(), ContentType.APPLICATION_JSON); //<--THIS DOESN'T SEEM TO WORK    
        StringBuilder buffer = new StringBuilder();
        buffer.append("form-data");

        String contentDisposition = buffer.toString();

        FormBodyPartBuilder partBuilder = FormBodyPartBuilder.create("application/json", json);
        partBuilder.setField(MIME.CONTENT_DISPOSITION, contentDisposition);

        FormBodyPart fbp = partBuilder.build();

        return fbp;
    }

public HttpRequestBase build（）引发UnsupportedEncodingException{
HttpPost-HttpPost=newhttppost（“https://{server}/restapi/{apiVersion}/accounts/{accountId}/envelopes”）；
MultipartEntityBuilder=MultipartEntityBuilder.create（）；
setContentType（ContentType.MULTIPART\u FORM\u DATA）；
builder.setMode（HttpMultipartMode.BROWSER_兼容）；
建造商。立法院（“AAA”）；
//添加表单主体
addPart（generateJsonFormBodyPart（））；
//添加文件体
builder.addPart（generateFileFormBodyPart（））；//我确信这是处理StringBody时FormBodyPart.build（）的Apache Http Mime中的一个错误。4.5.2发行说明中的证据表明，其他“body”类型的错误修复没有输出“Content Type”。我将记录一个缺陷

解决方法：

private FormBodyPart generateJsonFormBodyPart() throws UnsupportedEncodingException{
    StringBody json = new StringBody(getMyJsonStuff(), ContentType.APPLICATION_JSON); //<--THE GOGGLES, THEY DO NOTHING!!

    StringBuilder buffer = new StringBuilder();
    buffer.append("form-data");
    buffer.append("\r\n");
    buffer.append("Content-Type: application/json"); //<--tack this on to the 

    String kludgeForDispositionAndContentType = buffer.toString();

    FormBodyPartBuilder partBuilder = FormBodyPartBuilder.create("stuff", json);
    partBuilder.setField(MIME.CONTENT_DISPOSITION, kludgeForDispositionAndContentType);

    FormBodyPart fbp = partBuilder.build();

    return fbp;
}

private FormBodyPart generateJsonFormBodyPart（）引发不支持的编码异常{
StringBody json=新的StringBody（getMyJsonStuff（），ContentType.APPLICATION_json）//