Java HTTP发布多部分

Question

I'm trying to send an HTTP Post Multipart request to a local server in JAVA. I'm trying to send the following:

{
 "content-disposition": "form-data; name=\"metadata\"",
"content-type": "application/x-dmas+json",
 "body":         JSON.stringify(client_req)
},
{
"content-disposition": "attachment; filename=\"" + file + "\"; name=\"file\"",
"content-type": "application/octet-stream",
 "body":         [file content]
}

I've looked into Apache HTTP components, but it doesn't let me specify the content-type and disposition for each part. Here's what I've written in JAVA using the Apache HTTP API:

`CloseableHttpClient httpclient = HttpClients.createDefault();

    try {
        HttpPost httppost = new HttpPost("IP");

        FileBody bin = new FileBody(new File(args[0]), "application/octet-stream");
        StringBody hash = new StringBody("{\"hash\": \"\", \"policy\": {\"retention_permitted\": true, \"distribution\": \"global\"}}", ContentType.create("application/x-dmas+json"));

        HttpEntity reqEntity = MultipartEntityBuilder.create()
                .addPart("metadata", hash)
                .addPart("file", bin)
                .build();


        httppost.setEntity(reqEntity);

`

Answer 1

FilePart和StringPart的构造函数参数和方法，与它们一起组成组成多部分请求的Part []，可以提供此信息。

Answer 2

Probably it is too late but as reference for anyone looking the answer for the same question, there is several methods in the MultipartEntityBuilder class that allow you to set the content-type and content-disposition for each part. For example,

• addBinaryBody(String name, File file, ContentType contentType, String filename)
• addTextBody(String name, String text, ContentType contentType)

If we use the above methods in your example,

CloseableHttpClient httpClient = HttpClients.createDefault();
HttpPost uploadFile = new HttpPost("http://url-to-post/");

MultipartEntityBuilder builder = MultipartEntityBuilder.create();
String jsonStr = "{\"hash\": \"\", \"policy\": {\"retention_permitted\": true, \"distribution\": \"global\"}}";
builder.addTextBody("metadata", jsonStr, ContentType.create("application/x-dmas+json"));
builder.addBinaryBody("file", new File("/path/to/file"),
    ContentType.APPLICATION_OCTET_STREAM, "filename");

HttpEntity multipart = builder.build();
uploadFile.setEntity(multipart);
HttpResponse response = httpClient.execute(uploadFile);