后端springmvc，前端html5的FormData实现文件断点上传

package com.test.controller;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.util.UUID;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.FilenameUtils;
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.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;

@Controller
public class UploadController {

	@ResponseBody // 返回rest json
	@RequestMapping(value = {"/rest/saveUploadFileAsChunk"}, method = RequestMethod.POST, produces = "application/json")
	public File saveUploadFileAsChunk(@RequestParam(required = false) MultipartFile file,
			@RequestParam(required = true) Integer chunk,  // 分割块数
			@RequestParam(required = true) Integer chunks,  // 总分割数
			@RequestParam(required = true) String tempFileName //临时文件名  必须带后缀名
			) throws Exception{
		if(null != file){
			// 保存临时文件
			String chunkName = tempFileName;
            if (chunk != null) {
                chunkName = chunk + "_" + tempFileName;
            }
			File savedFile = new File("普通存放文件的路径", chunkName);
			if (!savedFile.getParentFile().exists())
				savedFile.getParentFile().mkdirs();
			file.transferTo(savedFile);  //将MultipartFile转存到file对象
		}
		
		//如果到最后一个分割块，则做合并处理
		if (chunk != null && chunk + 1 == chunks) {
			String newFileName = UUID.randomUUID().toString().replace("-", "").concat(".").concat(FilenameUtils.getExtension(tempFileName));
			BufferedOutputStream outputStream = new BufferedOutputStream(new FileOutputStream(new File("普通存放文件的路径", newFileName)));
			// 遍历文件合并  chunks，循环将文件写入新的文件中，并且删除之前的临时文件  
            for (int i = 0; i < chunks; i++) {
                File tempFile = new File("普通存放文件的路径", i + "_" + tempFileName);
                byte[] bytes = FileUtils.readFileToByteArray(tempFile);   //将file对象解析城byte数组
                outputStream.write(bytes);
                outputStream.flush();
                tempFile.delete();
            }
            outputStream.flush();
            outputStream.close();
            File reallyFile = new File("普通存放文件的路径", newFileName);  //reallyFile即最后合并的文件
            return reallyFile;
		}
		return null;
	}
}

var setsize = 10 * 1024;   //1024字节 = 1KB * 10  即每次10k

/**

*参数filepath就是本地文件路径，主要就是用于放在localStorage中确定唯一性
file ： js的Blob对象
*/
function uplaod(filepath,file){
	var filesize = file.size;
	var filecount = filesize/setsize;   //计算出可以分成几块

	var i = localStorage.getItem(filepath);
	i = (i!=null && i!="")?parseInt(i):0;

	if(i < filecount){
		//新建一个FormData对象
		var formData = new FormData(); //++++++++++
		var blobfile;
		if((filesize - i * setsize) > setsize){
		    blobfile = file.slice(i*setsize,(i+1)*setsize);
		}else{
		    //代表是最后一此了
		    blobfile = file.slice(i*setsize,filesize);
		}

		formData.append('chunk', i); //++++++++++当前文件块
		formData.append('chunks', Math.ceil(filecount)); //++++++++++  总块数
		formData.append("tempFileName",fileName);   //临时文件名 带uuid的
		formData.append('file', blobfile);

		if(i < filecount){
		$.ajax({
		    url: PATROL_CONSTANTS.SRV_URL+"/rest/saveUploadFileAsChunk",
		    type: 'POST',
		    data: formData,
		    processData: false,
		    contentType: false,
		    success: function (responseStr) {
		        localStorage.setItem(filepath,i+1);
		        var rs = filecount <= 0 ? "0%" : (Math.round((i+1) / Math.ceil(filecount) * 10000) / 100.00 + "%");
		        console.log("进度百分比："+rs);
		        
		        uploadFile(filepath,file);  //递归调用
		    },
		    error: function (responseStr) {
		        console.log("上传失败,重复尝试!");
		        console.log(responseStr);
		        uploadFile(filepath,file);
		    }
		});
	}else{
		//上传完成后,则将对应的localStorage移除掉
        localStorage.removeItem(filepath);
	}
}