okhttp实现断点上传

前言

之前项目需要上传大文件的功能，上传大文件经常遇到上传一半由于网络或者其他一些原因上传失败。然后又得重新上传（很麻烦），所以就想能不能做个断点上传的功能。于是网上搜索，发现市面上很少有断点上传的案例，有找到一个案例也是采用SOCKET作为上传方式（大文件上传，不适合使用POST,GET形式）。由于大文件夹不适合http上传的方式，所以就想能不能把大文件切割成n块小文件，然后上传这些小文件，所有小文件全部上传成功后再在服务器上进行拼接。这样不就可以实现断点上传，又解决了http不适合上传大文件的难题了吗！！！

原理分析

*******Android客户端********

首先，android端调用服务器接口1，参数为filename（服务器标识判断是否上传过）

如果存在filename，说明之前上传过，则续传；如果没有，则从零开始上传。

然后，android端调用服务器接口2，传入参数name，chunck（传到第几块），chuncks（总共多少块）

*******服务器端********

接口一：根据上传文件名称filename 判断是否之前上传过，没有则返回客户端chunck=1，有则读取记录chunck并返回。

接口二：上传文件，如果上传块数chunck=chuncks，遍历所有块文件拼接成一个完整文件。

*******服务端源代码********

服务器接口1

@WebServlet(urlPatterns = { "/ckeckFileServlet" })
public class CkeckFileServlet extends HttpServlet {

    private FileUploadStatusServiceI statusService;
    String repositoryPath;
    String uploadPath;

    @Override
    public void init(ServletConfig config) throws ServletException {
        ServletContext servletContext = config.getServletContext();
        WebApplicationContext context = WebApplicationContextUtils.getWebApplicationContext(servletContext);
        statusService = (FileUploadStatusServiceI) context.getBean("fileUploadStatusServiceImpl");

        repositoryPath = FileUtils.getTempDirectoryPath();
        uploadPath = config.getServletContext().getRealPath("datas/uploader");
        File up = new File(uploadPath);
        if (!up.exists()) {
            up.mkdir();
        }
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // TODO Auto-generated method stub

        String fileName = new String(req.getParameter("filename"));
        //String chunk = req.getParameter("chunk");
        //System.out.println(chunk);
        System.out.println(fileName);
        resp.setContentType("text/json; charset=utf-8");

        TfileUploadStatus file = statusService.get(fileName);

        try {
            if (file != null) {
                int schunk = file.getChunk();
                deleteFile(uploadPath + schunk + "_" + fileName);
                //long off = schunk * Long.parseLong(chunkSize);
                resp.getWriter().write("{\"off\":" + schunk + "}");

            } else {
                resp.getWriter().write("{\"off\":1}");
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

服务器接口2

@WebServlet(urlPatterns = { "/uploaderWithContinuinglyTransferring" })
public class UploaderServletWithContinuinglyTransferring extends HttpServlet {

    private static final long serialVersionUID = 1L;

    private FileUploadStatusServiceI statusService;
    String repositoryPath;
    String uploadPath;

    @Override
    public void init(ServletConfig config) throws ServletException {
        ServletContext servletContext = config.getServletContext();
        WebApplicationContext context = WebApplicationContextUtils.getWebApplicationContext(servletContext);
        statusService = (FileUploadStatusServiceI) context.getBean("fileUploadStatusServiceImpl");

        repositoryPath = FileUtils.getTempDirectoryPath();
        System.out.println("临时目录：" + repositoryPath);
        uploadPath = config.getServletContext().getRealPath("datas/uploader");
        System.out.println("目录：" + uploadPath);
        File up = new File(uploadPath);
        if (!up.exists()) {
            up.mkdir();
        }
    }
    @SuppressWarnings("unchecked")
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setCharacterEncoding("UTF-8");
        Integer schunk = null;// 分割块数
        Integer schunks = null;// 总分割数
        String name = null;// 文件名
        BufferedOutputStream outputStream = null;
        if (ServletFileUpload.isMultipartContent(request)) {
            try {
                DiskFileItemFactory factory = new DiskFileItemFactory();
                factory.setSizeThreshold(1024);
                factory.setRepository(new File(repositoryPath));// 设置临时目录
                ServletFileUpload upload = new ServletFileUpload(factory);
                upload.setHeaderEncoding("UTF-8");
                upload.setSizeMax(5 * 1024 * 1024 * 1024);// 设置附近大小
                List<FileItem> items = upload.parseRequest(request);
                // 生成新文件名

                String newFileName = null;
                for (FileItem item : items) {
                    if (!item.isFormField()) {// 如果是文件类型
                        name = newFileName;// 获得文件名
                        if (name != null) {
                            String nFname = newFileName;
                            if (schunk != null) {
                                nFname = schunk + "_" + name;
                            }
                            File savedFile = new File(uploadPath, nFname);
                            item.write(savedFile);
                        }
                    } else {
                        // 判断是否带分割信息
                        if (item.getFieldName().equals("chunk")) {
                            schunk = Integer.parseInt(item.getString());
                            //System.out.println(schunk);
                        }
                        if (item.getFieldName().equals("chunks")) {
                            schunks = Integer.parseInt(item.getString());
                        }

                        if (item.getFieldName().equals("name")) {
                            newFileName = new String(item.getString());
                        }
                    }
                }
                //System.out.println(schunk + "/" + schunks);
                if (schunk != null && schunk == 1) {
                    TfileUploadStatus file = statusService.get(newFileName);
                    if (file != null) {
                        statusService.updateChunk(newFileName, schunk);
                    } else {
                        statusService.add(newFileName, schunk, schunks);
                    }

                } else {
                    TfileUploadStatus file = statusService.get(newFileName);
                    if (file != null) {
                        statusService.updateChunk(newFileName, schunk);
                    }
                }
                if (schunk != null && schunk.intValue() == schunks.intValue()) {
                    outputStream = new BufferedOutputStream(new FileOutputStream(new File(uploadPath, newFileName)));
                    // 遍历文件合并
                    for (int i = 1; i <= schunks; i++) {
                        //System.out.println("文件合并:" + i + "/" + schunks);
                        File tempFile = new File(uploadPath, i + "_" + name);
                        byte[] bytes = FileUtils.readFileToByteArray(tempFile);
                        outputStream.write(bytes);
                        outputStream.flush();
                        tempFile.delete();
                    }
                    outputStream.flush();
                }
                response.getWriter().write("{\"status\":true,\"newName\":\"" + newFileName + "\"}");
            } catch (FileUploadException e) {
                e.printStackTrace();
                response.getWriter().write("{\"status\":false}");
            } catch (Exception e) {
                e.printStackTrace();
                response.getWriter().write("{\"status\":false}");
            } finally {
                try {
                    if (outputStream != null)
                        outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

}

*******android端源码********

UploadTask 上传线程类

package com.mainaer.wjoklib.okhttp.upload;

import android.database.sqlite.SQLiteDatabase;
import android.os.Environment;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.text.TextUtils;

import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.text.DecimalFormat;
import java.util.HashMap;
import java.util.Map;

import okhttp3.Headers;
import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

/**
 * 上传线程
 *
 * @author hst
 * @date 2016/9/6 .
 */
    public class UploadTask implements Runnable {

    private static String FILE_MODE = "rwd";
    private OkHttpClient mClient;
    private SQLiteDatabase db;
    private UploadTaskListener mListener;

    private Builder mBuilder;
    private String id;// task id
    private String url;// file url
    private String fileName; // File name when saving
    private int uploadStatus;
    private int chunck, chuncks;//流块
    private int position;

    private int errorCode;
    static String BOUNDARY = "----------" + System.currentTimeMillis();
    public static final MediaType MEDIA_TYPE_MARKDOWN = MediaType.parse("multipart/form-data;boundary=" + BOUNDARY);

    private UploadTask(Builder builder) {
        mBuilder = builder;
        mClient = new OkHttpClient();
        this.id = mBuilder.id;
        this.url = mBuilder.url;
        this.fileName = mBuilder.fileName;
        this.uploadStatus = mBuilder.uploadStatus;
        this.chunck = mBuilder.chunck;
        this.setmListener(mBuilder.listener);
        // 以kb为计算单位
    }

    @Override
    public void run() {
        try {
            int blockLength = 1024 * 1024;
            File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+ File.separator +fileName);
            if (file.length() % blockLength == 0) {
                chuncks = (int) file.length() / blockLength;
            } else {
                chuncks = (int) file.length() / blockLength + 1;

            }
            while (chunck <= chuncks&&uploadStatus!= UploadStatus.UPLOAD_STATUS_PAUSE&&uploadStatus!= UploadStatus.UPLOAD_STATUS_ERROR)
            {

                uploadStatus = UploadStatus.UPLOAD_STATUS_UPLOADING;
                Map<String, String> params = new HashMap<String, String>();
                params.put("name", fileName);
                params.put("chunks", chuncks + "");
                params.put("chunk", chunck + "");
                final byte[] mBlock = FileUtils.getBlock((chunck - 1) * blockLength, file, blockLength);
                MultipartBody.Builder builder = new MultipartBody.Builder()
                        .setType(MultipartBody.FORM);
                addParams(builder, params);
                RequestBody requestBody = RequestBody.create(MEDIA_TYPE_MARKDOWN, mBlock);
                builder.addFormDataPart("mFile", fileName, requestBody);
                Request request = new Request.Builder()
                        .url(url+ "uploaderWithContinuinglyTransferring")
                        .post(builder.build())
                        .build();
                Response response = null;
                response = mClient.newCall(request).execute();
                if (response.isSuccessful()) {
                    onCallBack();
                    chunck++;
                   /* if (chunck <= chuncks) {
                         run();
                    }*/
                }
                else
                {
                    uploadStatus = UploadStatus.UPLOAD_STATUS_ERROR;
                    onCallBack();
                }

            }
        } catch (IOException e) {
            uploadStatus = UploadStatus.UPLOAD_STATUS_ERROR;
            onCallBack();
            e.printStackTrace();
        }
    }

/*    *//**
     * 删除数据库文件和已经上传的文件
     *//*
    public void cancel() {
        if (mListener != null)
            mListener.onCancel(UploadTask.this);
    }*/

    /**
     * 分发回调事件到ui层
     */
    private void onCallBack() {
        mHandler.sendEmptyMessage(uploadStatus);
        // 同步manager中的task信息
        //UploadManager.getInstance().updateUploadTask(this);
    }

    Handler mHandler = new Handler(Looper.getMainLooper()) {
        @Override
        public void handleMessage(Message msg) {
            int code = msg.what;
            switch (code) {
                // 上传失败
                case UploadStatus.UPLOAD_STATUS_ERROR:
                    mListener.onError(UploadTask.this, errorCode,position);
                    break;
                // 正在上传
                case UploadStatus.UPLOAD_STATUS_UPLOADING:
                    mListener.onUploading(UploadTask.this, getDownLoadPercent(), position);
                 // 暂停上传
                    break;
                case UploadStatus.UPLOAD_STATUS_PAUSE:
                    mListener.onPause(UploadTask.this);
                    break;

            }
        }
    };

    private String getDownLoadPercent() {
        String baifenbi = "0";// 接受百分比的值
        if (chunck >= chuncks) {
            return "100";
        }
        double baiy = chunck * 1.0;
        double baiz = chuncks * 1.0;
        // 防止分母为0出现NoN
        if (baiz > 0) {
            double fen = (baiy / baiz) * 100;
            //NumberFormat nf = NumberFormat.getPercentInstance();
            //nf.setMinimumFractionDigits(2); //保留到小数点后几位
            // 百分比格式，后面不足2位的用0补齐
            //baifenbi = nf.format(fen);
            //注释掉的也是一种方法
            DecimalFormat df1 = new DecimalFormat("0");//0.00
            baifenbi = df1.format(fen);
        }
        return baifenbi;
    }

    private String getFileNameFromUrl(String url) {
        if (!TextUtils.isEmpty(url)) {
            return url.substring(url.lastIndexOf("/") + 1);
        }
        return System.currentTimeMillis() + "";
    }

    private void close(Closeable closeable) {
        try {
            closeable.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void setClient(OkHttpClient mClient) {
        this.mClient = mClient;
    }

    public Builder getBuilder() {
        return mBuilder;
    }

    public void setBuilder(Builder builder) {
        this.mBuilder = builder;
    }

    public String getId() {
        if (!TextUtils.isEmpty(id)) {
        } else {
            id = url;
        }
        return id;
    }

    public String getUrl() {
        return url;
    }

    public String getFileName() {
        return fileName;
    }

    public void setUploadStatus(int uploadStatus) {
        this.uploadStatus = uploadStatus;
    }

    public int getUploadStatus() {
        return uploadStatus;
    }

    public void setmListener(UploadTaskListener mListener) {
        this.mListener = mListener;
    }

    public static class Builder {
        private String id;// task id
        private String url;// file url
        private String fileName; // File name when saving
        private int uploadStatus = UploadStatus.UPLOAD_STATUS_INIT;
        private int chunck;//第几块
        private UploadTaskListener listener;

        /**
         * 作为上传task开始、删除、停止的key值，如果为空则默认是url
         *
         * @param id
         * @return
         */
        public Builder setId(String id) {
            this.id = id;
            return this;
        }

        /**
         * 上传url（not null）
         *
         * @param url
         * @return
         */
        public Builder setUrl(String url) {
            this.url = url;
            return this;
        }

        /**
         * 设置上传状态
         *
         * @param uploadStatus
         * @return
         */
        public Builder setUploadStatus(int uploadStatus) {
            this.uploadStatus = uploadStatus;
            return this;
        }

        /**
         * 第几块
         *
         * @param chunck
         * @return
         */
        public Builder setChunck(int chunck) {
            this.chunck = chunck;
            return this;
        }

        /**
         * 设置文件名
         *
         * @param fileName
         * @return
         */
        public Builder setFileName(String fileName) {
            this.fileName = fileName;
            return this;
        }

        /**
         * 设置上传回调
         *
         * @param listener
         * @return
         */
        public Builder setListener(UploadTaskListener listener) {
            this.listener = listener;
            return this;
        }

        public UploadTask build() {
            return new UploadTask(this);
        }
    }

    private void addParams(MultipartBody.Builder builder, Map<String, String> params) {
        if (params != null && !params.isEmpty()) {
            for (String key : params.keySet()) {
                builder.addPart(Headers.of("Content-Disposition", "form-data; name=\"" + key + "\""),
                        RequestBody.create(null, params.get(key)));
            }
        }
    }

}

UploadManager上传管理器

package com.mainaer.wjoklib.okhttp.upload;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

import okhttp3.OkHttpClient;

/**
 * 上传管理器
 *
 * @author wangjian
 * @date 2016/5/13 .
 */
public class UploadManager {

    private static Context mContext;

    private static SQLiteDatabase db;
    private OkHttpClient mClient;

    private int mPoolSize = 20;
    // 将执行结果保存在future变量中
    private Map<String, Future> mFutureMap;
    private ExecutorService mExecutor;
    private Map<String, UploadTask> mCurrentTaskList;

    static UploadManager manager;

    /**
     * 方法加锁，防止多线程操作时出现多个实例
     */
    private static synchronized void init() {
        if (manager == null) {
            manager = new UploadManager();
        }
    }

    /**
     * 获得当前对象实例
     *
     * @return 当前实例对象
     */
    public final static UploadManager getInstance() {
        if (manager == null) {
            init();
        }
        return manager;
    }

    /**
     * 管理器初始化，建议在application中调用
     *
     * @param context
     */
    public static void init(Context context, SQLiteDatabase db1) {
        mContext = context;
        db = db1;
        getInstance();
    }

    public UploadManager() {
        initOkhttpClient();

        // 初始化线程池
        mExecutor = Executors.newFixedThreadPool(mPoolSize);
        mFutureMap = new HashMap<>();
        mCurrentTaskList = new HashMap<>();
    }

    /**
     * 初始化okhttp
     */
    private void initOkhttpClient() {
        OkHttpClient.Builder okBuilder = new OkHttpClient.Builder();
        okBuilder.connectTimeout(1000, TimeUnit.SECONDS);
        okBuilder.readTimeout(1000, TimeUnit.SECONDS);
        okBuilder.writeTimeout(1000, TimeUnit.SECONDS);
        mClient = okBuilder.build();
    }

    /**
     * 添加上传任务
     *
     * @param uploadTask
     */
    public void addUploadTask(UploadTask uploadTask) {
        if (uploadTask != null && !isUploading(uploadTask)) {
            uploadTask.setClient(mClient);
            uploadTask.setUploadStatus(UploadStatus.UPLOAD_STATUS_INIT);
            // 保存上传task列表
            mCurrentTaskList.put(uploadTask.getId(), uploadTask);
            Future future = mExecutor.submit(uploadTask);
            mFutureMap.put(uploadTask.getId(), future);
        }
    }

    private boolean isUploading(UploadTask task) {
        if (task != null) {
            if (task.getUploadStatus() == UploadStatus.UPLOAD_STATUS_UPLOADING) {
                return true;
            }
        }
        return false;
    }

    /**
     * 暂停上传任务
     *
     * @param id 任务id
     */
    public void pause(String id) {
        UploadTask task = getUploadTask(id);
        if (task != null) {
            task.setUploadStatus(UploadStatus.UPLOAD_STATUS_PAUSE);
        }
    }

    /**
     * 重新开始已经暂停的上传任务
     *
     * @param id 任务id
     */
    public void resume(String id, UploadTaskListener listener) {
        UploadTask task = getUploadTask(id);
        if (task != null) {
            addUploadTask(task);
        }
    }

/*    *//**
     * 取消上传任务(同时会删除已经上传的文件，和清空数据库缓存)
     *
     * @param id       任务id
     * @param listener
     *//*
    public void cancel(String id, UploadTaskListener listener) {
        UploadTask task = getUploadTask(id);
        if (task != null) {
            mCurrentTaskList.remove(id);
            mFutureMap.remove(id);
            task.setmListener(listener);
            task.cancel();
            task.setDownloadStatus(UploadStatus.DOWNLOAD_STATUS_CANCEL);
        }
    }*/

    /**
     * 实时更新manager中的task信息
     *
     * @param task
     */
    public void updateUploadTask(UploadTask task) {
        if (task != null) {
            UploadTask currTask = getUploadTask(task.getId());
            if (currTask != null) {
                mCurrentTaskList.put(task.getId(), task);
            }
        }
    }

    /**
     * 获得指定的task
     *
     * @param id task id
     * @return
     */
    public UploadTask getUploadTask(String id) {
        UploadTask currTask = mCurrentTaskList.get(id);
        if (currTask == null) {
                currTask = parseEntity2Task(new UploadTask.Builder().build());
                // 放入task list中
                mCurrentTaskList.put(id, currTask);
        }

        return currTask;
    }

    private UploadTask parseEntity2Task(UploadTask currTask) {

        UploadTask.Builder builder = new UploadTask.Builder()//
                .setUploadStatus(currTask.getUploadStatus())
                .setFileName(currTask.getFileName())//
                .setUrl(currTask.getUrl())
                .setId(currTask.getId());

            currTask.setBuilder(builder);

        return currTask;
    }
} 

FileUtils文件分块类

package com.mainaer.wjoklib.okhttp.upload;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;

public class FileUtils {

    public static byte[] getBlock(long offset, File file, int blockSize) {
        byte[] result = new byte[blockSize];
        RandomAccessFile accessFile = null;
        try {
            accessFile = new RandomAccessFile(file, "r");
            accessFile.seek(offset);
            int readSize = accessFile.read(result);
            if (readSize == -1) {
                return null;
            } else if (readSize == blockSize) {
                return result;
            } else {
                byte[] tmpByte = new byte[readSize];
                System.arraycopy(result, 0, tmpByte, 0, readSize);
                return tmpByte;
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (accessFile != null) {
                try {
                    accessFile.close();
                } catch (IOException e1) {
                }
            }
        }
        return null;
    }

}

UploadTaskListener 接口类 

package com.mainaer.wjoklib.okhttp.upload;

import com.mainaer.wjoklib.okhttp.download.DownloadStatus;

import java.io.File;

/**
 * Created by hst on 16/9/21.
 */
public interface UploadTaskListener {
    /**
     * 上传中
     *
     * @param percent
     * @param uploadTask
     */
    void onUploading(UploadTask uploadTask, String percent,int position)

    /**
     * 上传成功
     *
     * @param file
     * @param uploadTask
     */
    void onUploadSuccess(UploadTask uploadTask, File file);

    /**
     * 上传失败
     *
     * @param uploadTask
     * @param errorCode    {@link DownloadStatus}
     */
    void onError(UploadTask uploadTask, int errorCode,int position);   

    /**
    * 上传暂停
    *
    * @param uploadTask
   *
   */
   void onPause(UploadTask uploadTask);
 }

android源码地址：https://github.com/handsometong/okhttpUpLoader