JS异步文件分片断点上传

在项目中有时会遇到大文件上传，经常会出现链接超时的问题，所以就需要使用文件分片上传的方式来上传大文件。实现原理就是，在前端将文件分成指定大小的“文件块”，分成多次上传，每次上传前先向后台查询已经上传成功的文件的大小，然后从指定的位置切割一块文件，进行上传，后台接收到文件块后追加到指定的文件中。
这篇博客适合有一些后台基础的朋友，或者有后台配合的前端。
这里需要后台提供两个接口，一个上传文件的接口，一个查询已上传文件大小的接口。

前端代码：http://c7.gg/cd5XT

这里放上后台主要代码

package com.fs.controller;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.util.Iterator;
import java.util.Map;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;

import org.apache.commons.lang3.StringUtils;
import org.csource.ClientGlobal;
import org.csource.common.MyException;
import org.csource.fastdfs.FileInfo;
import org.csource.fastdfs.StorageClient;
import org.csource.fastdfs.TrackerClient;
import org.csource.fastdfs.TrackerServer;
import org.junit.Test;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisShardInfo;

import com.alibaba.fastjson.JSON;
import com.fs.entity.UploadedFileInfo;
import com.fs.util.UploadUtil;

/**
* @author admin
*
* 2016年12月20日下午8:59:38
*/
@Controller
public class FastDFSUpLoadController {

@Resource
private UploadUtil uploadUtil;

    @RequestMapping(value = "v1/uploadSize", method = RequestMethod.POST)
    @ResponseBody
    public Long uploadSize(HttpServletRequest request) {

        String name = request.getParameter("name");
        Long size = Long.parseLong(request.getParameter("size"));
        try {
            JedisShardInfo jedisShardInfo = new JedisShardInfo("192.168.0.12");
            Jedis jedis = new Jedis(jedisShardInfo);
            String str = jedis.get(name);

UploadedFileInfo uploadedFileInfo = null;

            // 如果首次上传，已上传大小为 0
            if (StringUtils.isEmpty(str)) {
                uploadedFileInfo = new UploadedFileInfo();
                jedis.set(name, JSON.toJSONString(uploadedFileInfo));
                jedis.close();
                return 0L;
            }

uploadedFileInfo = JSON.parseObject(str, UploadedFileInfo.class);

            jedis.close();
            //已经全部上传
            if(size <= uploadedFileInfo.getSize()){

System.out.println("上传完成");

            }
             //UploadUtil.getFileInfo(uploadedFileInfo.getFileId());
            return uploadedFileInfo.getSize();
        } catch (Exception e) {
            e.printStackTrace();
            return 0L;
        }

}

    @RequestMapping(value = "v1/uploadFile", method = RequestMethod.POST)
    @ResponseBody
    public int upload(HttpServletRequest request) {
        // CommonsMultipartResolver resolver = new
        // CommonsMultipartResolver(request.getSession().getServletContext());
        MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest) request;
        Iterator<String> t = multiRequest.getFileNames();
        MultipartFile fileDetail = multiRequest.getFile(t.next());
        String name = request.getParameter("name");

JedisShardInfo jedisShardInfo = new JedisShardInfo("192.168.0.12");
Jedis jedis = new Jedis(jedisShardInfo);

UploadedFileInfo uploadedFileInfo = JSON.parseObject(jedis.get(name), UploadedFileInfo.class);
uploadedFileInfo.setFileName(name);

        String path = "d:/testUpload";
        File file = new File(path);
        if (!file.exists() && !file.isDirectory()) {
            boolean b = file.mkdirs();
        }

        RandomAccessFile randomFile = null;
        try {
            randomFile = new RandomAccessFile(path+"/"+name, "rw");
            randomFile.seek(randomFile.length());
            randomFile.write(fileDetail.getBytes());

            uploadedFileInfo.setLocalPath(path+"/"+name);
            uploadedFileInfo.setSize(randomFile.length());
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            try {
                randomFile.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        // 将上传文件信息保存到redis
        jedis.set(name, JSON.toJSONString(uploadedFileInfo));
        jedis.close();

return 0;
}
}

JS异步文件分片断点上传

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