java如何在安卓中将文件上传到服务器？

Question

如何使用volley library从移动设备向服务器发送文件（数据）

下面我列出了我的参数，请帮我解决这个问题

        Map<String, String> mHeaderPart= new HashMap<>();
            mHeaderPart.put("Content-type", "multipart/form-data;");
            mHeaderPart.put("Authorization", authorizationKey);


    //String part
            Map<String, String> mStringPart= new HashMap<>();
            mStringPart.put("candidate_id", SessionStores.getBullHornId(getActivity()));
            mStringPart.put("externalID", "portpolio");
            mStringPart.put("fileCount", "2");//number of files
            mStringPart.put("fileType", "SAMPLE");
            mStringPart.put("platform", "安卓");

//file param

     Map<String, File> mFilePartData= new HashMap<>();

在上面的文件参数中，我必须添加n个文件并将其发送到服务器。我如何从设备中获取文件，并使用param添加n个文件，并将其发送到服务器。如果有人可以，请给我建议

如果有人有使用截击发送多个文件的例子，请指导我。提前谢谢

Answer 1

Volly不提供在服务器上使用multi-part上传文件的直接方式

要使用volly上传多个文件，请执行以下步骤：

步骤1:创建一个名为MultipartRequest的新类。从volly扩展请求的java，如下所示：

import com.android.volley.AuthFailureError;

import com.android.volley.NetworkResponse;

import com.android.volley.ParseError;

import com.android.volley.Request;

import com.android.volley.Response;

import com.android.volley.VolleyLog;

import com.android.volley.toolbox.HttpHeaderParser;

import org.apache.http.HttpEntity;

import org.apache.http.entity.mime.MultipartEntityBuilder;

import org.apache.http.entity.mime.content.FileBody;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.IOException;

import java.io.UnsupportedEncodingException;

import java.util.HashMap;

import java.util.Map;

public class MultipartRequest extends Request<String> { private MultipartEntityBuilder entitybuilder = MultipartEntityBuilder.create(); HttpEntity entity;

    private HashMap<String, File> sendFile = new HashMap<>();

    /**
    * 
    * @param url               url
    * @param errorListener     volly error listenere
    * @param sendFile          HashMap with key as file name and value as file  object
    */

    public MultipartRequest(String url, Response.ErrorListener errorListener,   HashMap<String, File> sendFile) {
    super(Method.POST, url, errorListener);

    this.sendFile = sendFile;
    buildMultipartEntity();
    entity = entitybuilder.build();
    }

    private void buildMultipartEntity() {

    if (sendFile != null)
        for (Map.Entry<String, File> entry : sendFile.entrySet()) {
            entitybuilder.addPart(entry.getKey(), new    FileBody(entry.getValue()));

            // here you can set key as filename
            // value will be the file object to be upload

        }
    }

    @Override
    public String getBodyContentType() {
    return entity.getContentType().getValue();
    }

    @Override
    public byte[] getBody() throws AuthFailureError {
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    try {
        entity.writeTo(bos);
    } catch (IOException e) {
        VolleyLog.e("IOException writing to ByteArrayOutputStream");
    }
    return bos.toByteArray();
    }

    @Override
    protected Response<String> parseNetworkResponse(NetworkResponse networkResponse) {
    try {
        String json = new String(
                networkResponse.data,   HttpHeaderParser.parseCharset(networkResponse.headers));
        return Response.success(json, HttpHeaderParser.parseCacheHeaders(networkResponse));

    } catch (UnsupportedEncodingException e) {
        return Response.error(new ParseError(e));
    }
    }

    @Override
    protected void deliverResponse(String s) {

    //Your response

    }
}

第二步：

从你的活动中：

public void executeMultipart(String url,HashMap<String, File> fileData) { 
    try { MultipartRequest mRequest = new MultipartRequest(url , new Response.ErrorListener() { @Override public void onErrorResponse(VolleyError volleyError) {

            }
        },fileData);
        mRequest.setRetryPolicy(new DefaultRetryPolicy(
                (int) TimeUnit.SECONDS.toMillis(20),
                DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
                DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
    } catch (Exception e) {
        e.printStackTrace();
    }
    }

第3步：在应用程序构建中。gradle文件添加：

compile('org.apache.httpcomponents:httpmime:4.3.6') { exclude module: 'httpclient' }

注：来自API 22组织。阿帕奇。http。HttpEntity已被弃用，因此最好使用URLConnection或改型库，两者都有各自的优点和缺点