从 REST Web 服务向客户端发送文件的正确方法是什么? [英] what's the correct way to send a file from REST web service to client?

问题描述

我刚刚开始开发 REST 服务，但遇到了一个困难的情况:将文件从我的 REST 服务发送到我的客户端.到目前为止，我已经掌握了如何发送简单数据类型(字符串、整数等)的窍门，但发送文件是另一回事，因为文件格式太多，我什至不知道应该从哪里开始.我的 REST 服务是在 Java 上制作的，我使用的是 Jersey，我使用 JSON 格式发送所有数据.

I've just started to develop REST services, but I've come across a difficult situation: sending files from my REST service to my client. So far I've gotten the hang of how to send simple data types (strings, integers, etc) but sending a file is a different matter since there are so many file formats that I don't know where I should even begin. My REST service is made on Java and I'm using Jersey, I'm sending all the data using the JSON format.

我读过有关 base64 编码的文章，有人说这是一种很好的技术，也有人说这不是因为文件大小问题.正确的方法是什么?这是我项目中一个简单的资源类的外观:

I've read about base64 encoding, some people say it's a good technique, others say it isn't because of file size issues. What is the correct way? This is how a simple resource class in my project is looking:

import java.sql.SQLException;
import java.util.List;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Request;
import javax.ws.rs.core.UriInfo;

import com.mx.ipn.escom.testerRest.dao.TemaDao;
import com.mx.ipn.escom.testerRest.modelo.Tema;

@Path("/temas")
public class TemaResource {

    @GET
    @Produces({MediaType.APPLICATION_JSON})
    public List<Tema> getTemas() throws SQLException{

        TemaDao temaDao = new TemaDao();        
        List<Tema> temas=temaDao.getTemas();
        temaDao.terminarSesion();

        return temas;
    }
}

我猜发送文件的代码类似于:

I'm guessing the code for sending a file would be something like:

import java.sql.SQLException;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;

@Path("/resourceFiles")
public class FileResource {

    @GET
    @Produces({application/x-octet-stream})
    public File getFiles() throws SQLException{ //I'm not really sure what kind of data type I should return

        // Code for encoding the file or just send it in a data stream, I really don't know what should be done here

        return file;
    }
}

我应该使用什么样的注解?我看到有些人推荐使用 @Produces({application/x-octet-stream}) 的 @GET，这是正确的方法吗?我发送的文件是特定的，因此客户端不需要浏览文件.谁能指导我如何发送文件?我应该使用 base64 对其进行编码以将其作为 JSON 对象发送吗?或者编码不需要将其作为 JSON 对象发送?感谢您提供的任何帮助.

What kind of annotations should I use? I've seen some people recommend for a @GET using @Produces({application/x-octet-stream}), is that the correct way? The files I'm sending are specific ones so the client doesn't need to browse through the files. Can anyone guide me into how am I supposed to send the file? Should I encode it using base64 to send it as a JSON object? or the encoding isn't necessary to send it as a JSON object? Thanks for any help you may give.

推荐答案

我不建议在 base64 中编码二进制数据并将其包装在 JSON 中.它只会不必要地增加响应的大小并减慢速度.

I don't recommend encoding binary data in base64 and wrapping it in JSON. It will just needlessly increase the size of the response and slow things down.

使用 GET 和 application/octect-stream 使用 javax.ws.rs.core.Response(JAX-RS API 的一部分，因此您不会陷入困境泽西岛):

Simply serve your file data using GET and application/octect-streamusing one of the factory methods of javax.ws.rs.core.Response (part of the JAX-RS API, so you're not locked into Jersey):

@GET
@Produces(MediaType.APPLICATION_OCTET_STREAM)
public Response getFile() {
  File file = ... // Initialize this to the File path you want to serve.
  return Response.ok(file, MediaType.APPLICATION_OCTET_STREAM)
      .header("Content-Disposition", "attachment; filename="" + file.getName() + """ ) //optional
      .build();
}

如果您没有实际的 File 对象，而是一个 InputStream，Response.ok(entity, mediaType) 应该也能处理.

If you don't have an actual File object, but an InputStream, Response.ok(entity, mediaType) should be able to handle that as well.

这篇关于从 REST Web 服务向客户端发送文件的正确方法是什么?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！