Android开发 retrofit下载与上传

前言

 　　此博客只讲解retrofit下载与上传的使用,其实与其说是retrofit的下载与上传还不如说,依然是Okhttp的下载与上传.如果你需要了解retrofit入门请查看这篇博客(此博客不在详细讲解一些基础的东西):https://www.cnblogs.com/guanxinjing/p/11594249.html

下载

　　设置下载接口

public interface HttpList {

    @Streaming //注解这个请求将获取数据流,此后将不会这些获取的请求数据保存到内存中,将交与你操作.
    @GET
    Call<ResponseBody> download(@Url String url);


}

这里有一个很重要的东西! @Url属性, 这个属性是你导入的下载地址. 它可以是绝对地址和可以是相对地址,当你使用这个属性的时候,Retrofit设置基础Url的baseUrl("http://p.gdown.baidu.com/") 将自动判断地址是绝对还是相对,从而选择拼接Url还是替换Url !

　　请求下载

private void downloadFile() {
        final File file = new File(getExternalCacheDir(), "demo.apk");
        if (file.exists()) {
            file.delete();
        }

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("http://p.gdown.baidu.com/")//base的网络地址
                .callbackExecutor(Executors.newSingleThreadExecutor())//设置线程,如果不设置下载在读取流的时候就会报错
                .build();

        HttpList httpList = retrofit.create(HttpList.class);

        Call<ResponseBody> call = httpList.download(DOWNLOAD_URL_PATH);//下载地址  太长了所以我用DOWNLOAD_URL_PATH封装了一下,不要误解

        call.enqueue(new Callback<ResponseBody>() {
            @Override
            public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
                try {
                    long total = response.body().contentLength();//需要下载的总大小
                    long current = 0;
                    InputStream inputStream = response.body().byteStream();
                    FileOutputStream fileOutputStream = new FileOutputStream(file);
                    byte[] bytes = new byte[1024];
                    int len = 0;
                    while ((len = inputStream.read(bytes)) != -1) {
                        fileOutputStream.write(bytes, 0, len);
　　　　　　　　　　　　　　　fileOutputStream.flush();
                        current = current + len;
                        Log.e(TAG, "已经下载=" + current + " 需要下载=" + total);
                    }
                    fileOutputStream.flush();
                    fileOutputStream.close();
                    inputStream.close();

                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onFailure(Call<ResponseBody> call, Throwable t) {

            }
        });
    }

以上的下载实现的关键点,其实是ResponseBody,而这个其实就是okhttp的请求接口后返回的响应body. Retrofit并没有对这个进行封装,所以如果你了解okhttp的使用,应该是轻轻松松的.

上传

 　　上传一般有好几种情况:

  • 　　不需要进度的上传
  • 　　需要进度的上传
  • 　　批量上传

无进度的文件上传

　　接口服务类

public interface HttpList {
    @Multipart
    @POST("test/upfile")
    Call<ResponseBody> upFile(@Part MultipartBody.Part part);
}

注意这里的Body是 MultipartBody

　　上传实现

/**
     * 无进度上传
     */
    private void updateFile(){
        final File imageFile = new File(getExternalCacheDir() + "/image/demo.jpg");
        if (!imageFile.getParentFile().exists()){
            imageFile.getParentFile().mkdirs();
        }

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("http://www.doclever.cn:8090/mock/5ba0c147fa08107daa8c55c2/")
                .callbackExecutor(Executors.newSingleThreadExecutor())
                .build();
        HttpList list = retrofit.create(HttpList.class);

        //
        /*
         * "image/jpg" 是你要上传的文件的格式 这个格式并不是固定的,是根据你的项目使用那些何种key也有很多是使用下面这个:
         *  RequestBody requestFile = RequestBody.create(MediaType.parse("multipart/form-data"), imageFile);
         */
        RequestBody requestFile = RequestBody.create(MediaType.parse("image/jpg"), imageFile);


        //注意这里的file是对应MultipartBody上传文件的key名称
        MultipartBody.Part multipartBody = MultipartBody.Part.createFormData("file", imageFile.getName(), requestFile);

        Call<ResponseBody> call = list.upFile(multipartBody);
        call.enqueue(new Callback<ResponseBody>() {
            @Override
            public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
                try {
                    Log.e(TAG, "onResponse: 上传成功 "+response.body().string());
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }

            @Override
            public void onFailure(Call<ResponseBody> call, Throwable t) {

            }
        });


    }

有进度的文件上传

/**
     * 有进度的上传
     */
    private void updateFile(){
        final File imageFile = new File(getExternalCacheDir() + "/image/demo.jpg");
        if (!imageFile.getParentFile().exists()){
            imageFile.getParentFile().mkdirs();
        }

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("http://www.doclever.cn:8090/mock/5ba0c147fa08107daa8c55c2/")
                .callbackExecutor(Executors.newSingleThreadExecutor())
                .build();
        HttpList list = retrofit.create(HttpList.class);

        RequestBody requestFile = new RequestBody() {
            @Nullable
            @Override
            public MediaType contentType() {
                return MediaType.parse("image/jpg");//这里返回上传的格式 根据项目情况也可以切换成"multipart/form-data" 等等其他格式
            }

            @Override
            public void writeTo(BufferedSink sink) throws IOException {
                RandomAccessFile randomAccessFile = new RandomAccessFile(imageFile, "rw");
                long totalLength = 0;
                long currentUpLength = 0;
                if (totalLength == 0) {
                    totalLength = randomAccessFile.length();
                }
                byte[] bytes = new byte[2048];
                int len = 0;
                try {
                    while ((len = randomAccessFile.read(bytes)) != -1) {
                        sink.write(bytes, 0, len);
                        currentUpLength = currentUpLength + len;
                        Log.e(TAG, "writeTo: totalLength="+totalLength + " currentUpLength="+currentUpLength);
                    }
                }catch (Exception e){
                    Log.e(TAG, "上传中断");
                }finally {
                    randomAccessFile.close();//关闭流
                    Log.e(TAG, "流关闭");
                }

            }
        };

        MultipartBody.Part multipartBody = MultipartBody.Part.createFormData("file", imageFile.getName(), requestFile);

        Call<ResponseBody> call = list.upFile(multipartBody);
        call.enqueue(new Callback<ResponseBody>() {
            @Override
            public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
                try {
                    Log.e(TAG, "onResponse: 上传成功 "+response.body().string());
                } catch (IOException e) {
                    e.printStackTrace();
                }

            }

            @Override
            public void onFailure(Call<ResponseBody> call, Throwable t) {

            }
        });


    }

批量上传文件（无对应key的批量上传）

 　　接口服务类

public interface HttpList {
    @Multipart
    @POST("test/upfileList")
    Call<ResponseBody> upFileList(@Part List<MultipartBody.Part> partList);
}

其他与单个上传一致

批量上传文件（有对应key的批量上传）

 　　接口服务类

public interface HttpList {
    @Multipart
    @POST("test/upfileList")
    Call<ResponseBody> upFileList(@PartMap Map<String, RequestBody> map);
}

　　实现批量上传

private void updateFile3(){
        final File imageFile1 = new File(getExternalCacheDir() + "/image/demo_1.jpg");
        final File imageFile2 = new File(getExternalCacheDir() + "/image/demo_2.jpg");
        final File imageFile3 = new File(getExternalCacheDir() + "/image/demo_3.jpg");
        RequestBody requestFile1 = RequestBody.create(MediaType.parse("multipart/form-data"), imageFile1);
        RequestBody requestFile2 = RequestBody.create(MediaType.parse("multipart/form-data"), imageFile2);
        RequestBody requestFile3 = RequestBody.create(MediaType.parse("multipart/form-data"), imageFile3);
        Map<String, RequestBody> map = new HashMap<>();
        map.put("file1", requestFile1); //file1 就是需要上传每个文件的key名称
        map.put("file2", requestFile2);
        map.put("file3", requestFile3);

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("http://www.doclever.cn:8090/mock/5ba0c147fa08107daa8c55c2/")
                .callbackExecutor(Executors.newSingleThreadExecutor())
                .build();
        HttpList list = retrofit.create(HttpList.class);
        Call<ResponseBody> call = list.upFileList(map);
        call.enqueue(new Callback<ResponseBody>() {
            @Override
            public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
                //上传成功

            }

            @Override
            public void onFailure(Call<ResponseBody> call, Throwable t) {

            }
        });

    }

end

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原文地址：https://www.cnblogs.com/guanxinjing/p/11609328.html