如何为GSON编写发送流的类型适配器?

One of the fields of my class is filename. For serialization i'm going to write Gson type adapter (implements JsonSerializer<MyClass>) which should send file stream.

我的类的一个字段是文件名。对于序列化，我将编写Gson类型适配器(实现JsonSerializer )，它应该发送文件流。

The problem is that i don't want it to read all file data (stream) and hold it as string in the memory as memory size is limited (it's mobile device) and i have to send some another fields (filename f.e. below), so json should look like:

问题是，我不希望它读取所有的文件数据(流)，并把它作为内存中的字符串保存，因为内存大小是有限的(它是移动设备)，并且我必须发送一些其他字段(文件名f.e. e)，所以json应该是这样的:

data:
{
    filename:"filename.png"
    filedata:"(base64 file data stream here)"
}

What is the best way to send file data in network as a field in this case?

在这种情况下，将网络中的文件数据作为字段发送的最佳方式是什么?

PS. Network sending is done by Apache Http Client if it helps

网络发送是由Apache Http客户端完成的，如果它有帮助的话。

1 个解决方案

#1

It seems that it's not good architectural solution to mix json and large binary data within one request body. One can use http Multipart instead:

在一个请求体中混合json和大型二进制数据似乎不是很好的架构解决方案。可以使用http多部分代替:

    HttpPost request = new HttpPost(url);

    MultipartEntity multipartEntity = new MultipartEntity();
    request.setEntity(multipartEntity);

    // body
    try {
        multipartEntity.addPart("json", new StringBody(body, "application/json", Charset.forName("utf-8")));
    } catch (UnsupportedEncodingException e) {
        throw new ResourceLoadingException(e);
    }

    // files
    for (int i=0; i<filespaths.size(); i++) {
        String eachFilePath = filespaths.get(i);
        File file = new File(eachFilePath);
        multipartEntity.addPart("file" + String.valueOf(i), new FileBody(file));
    }

What about mobile devices Android does not support Multipart bodies but you can add support for it easily (if using Maven or Gradle):

那么移动设备呢? Android不支持多部分主体，但是你可以很容易地添加对多部分主体的支持(如果使用Maven或Gradle):

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpmime</artifactId>
    <version>4.2.5</version>
</dependency>

#1