2、分片上传参数实体类org.springframework.boot spring-boot-starter-data-redis com.github.tobato fastdfs-client 1.26.7
@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class MultipartFileParam {
private long chunkNumber;
private long chunkSize;
private long totalChunks;
private String identifier;
private MultipartFile file;
}
3、分片上传文件
分片上传文件的思想：首先，前端先加载检测文件大小，并将文件按照一定大小拆分成若干等分，同时为每一个分片文件按顺序标好序号；然后前端根据文件序号按顺序请求上传文件接口；最后，FastDFS将接收到的文件按顺序追加整合成完整的文件。
在实际工作中，分片上传文件会遇到一些问题，如：
前端请求上传文件不总是按照分片序号的顺序去请求重复上传分片文件
以下代码主要解决这两个问题：
//先检查已经上传到第几片了
String checkUploadChunkNum = (String)redisService.get(CommonConstant.uploadChunkNum+identifier);
if (checkUploadChunkNum==null && chunkNumber!=1){
//如果当前即将上传的分片不是第一片，而且又查询不到之前的之前已经存在的分片记录，则上传失败
throw new SystemException(ResultEnum.ERR.getCode(),"上传失败");
}else if (checkUploadChunkNum!=null && chunkNumber-1Long.valueOf(checkUploadChunkNum)){
//如果当前即将上传的分片序号-1大于已经上传的分片序号，说明提前上传了，需要等待前面序号的分片上传完才能开始上传
//循环最多执行100次，最多执行100*100/1000=10(秒)
int time = 100;
while (time>0){
//每次循环休眠100毫秒
Thread.sleep(100);
time--;
//每次循环检查已经上传分片的最新序号
checkUploadChunkNum = (String) redisService.get(CommonConstant.uploadChunkNum+identifier);
if (chunkNumber-1==Long.valueOf(checkUploadChunkNum)){
//如果当前准备上传的分片序号-1等于已经上传分片的最新序号，则跳出循环
break;
}
}
}
完整代码：
@RestController
public class FastDFSController {
private final Integer cacheTime = 60 * 60 * 24;
@Autowired
private AppendFileStorageClient appendFileStorageClient;
@Autowired
private RedisService redisService;
@PostMapping("/uploadFile")
public String uploadFile(MultipartFileParam param){
//当前第几分片
long chunkNumber = param.getChunkNumber();
//每个分片的大小
long chunkSize = param.getChunkSize();
//分片总数
long totalChunks = param.getTotalChunks();
//文件唯一标识
String identifier = param.getIdentifier();
//分块文件传输对象
MultipartFile file = param.getFile();
//文件后缀名
String fileName = FileUtil.extName(file.getOriginalFilename());
//历史上传文件大小
long historyUploadSize = (chunkNumber-1)*chunkSize;
//包含组和服务器文件路径，例如：StorePath [group=group1, path=M00/00/00/xxx.xxx]
StorePath storePath = null;
//服务器文件路径，例如：M00/00/00/xxx.xxx
String groundPath;
try{
//先检查已经上传到第几片了
String checkUploadChunkNum = (String)redisService.get(CommonConstant.uploadChunkNum+identifier);
if (checkUploadChunkNum==null && chunkNumber!=1){
//如果当前即将上传的分片不是第一片，而且又查询不到之前的之前已经存在的分片记录，则上传失败
throw new SystemException(ResultEnum.ERR.getCode(),"上传失败");
}else if (checkUploadChunkNum!=null && chunkNumber-1Long.valueOf(checkUploadChunkNum)){
//如果当前即将上传的分片序号-1大于已经上传的分片序号，说明提前上传了，需要等待前面序号的分片上传完才能开始上传
//循环最多执行100次，最多执行100*100/1000=10(秒)
int time = 100;
while (time>0){
//每次循环休眠100毫秒
Thread.sleep(100);
time--;
//每次循环检查已经上传分片的最新序号
checkUploadChunkNum = (String) redisService.get(CommonConstant.uploadChunkNum+identifier);
if (chunkNumber-1==Long.valueOf(checkUploadChunkNum)){
//如果当前准备上传的分片序号-1等于已经上传分片的最新序号，则跳出循环
break;
}
}
}
//若上传的是第一片，且只有一片，上传完就结束
if (chunkNumber == 1 ){
if (checkUploadChunkNum !=null){
throw new SystemException(ResultEnum.ERR.getCode(),"第一片已经上传");
}
storePath = appendFileStorageClient.uploadAppenderFile(CommonConstant.DEFAULT_GROUP, file.getInputStream(),file.getSize(), fileName);
//记录当前传入第一片
redisService.set(CommonConstant.uploadChunkNum+identifier,String.valueOf(chunkNumber),cacheTime);
if (storePath == null){
throw new SystemException(ResultEnum.ERR.getCode(),"第一片上传失败");
}
//总共只有一片就返回
if (totalChunks == 1){
//如果只有一片，直接返回结果
return storePath.getPath();
}else {
//记录已存存文件路径
redisService.set(CommonConstant.fastDfsPath+identifier,storePath.getPath(),cacheTime);
return "第："+chunkNumber+"上传成功";
}
} else {
if (chunkNumber-1 == Long.valueOf(checkUploadChunkNum)){
//获取已存文件路径
groundPath = (String) redisService.get(CommonConstant.fastDfsPath+identifier);
if (groundPath == null){
throw new SystemException(ResultEnum.ERR.getCode(),"获取文件路径失败");
}
//追加文件
appendFileStorageClient.modifyFile(CommonConstant.DEFAULT_GROUP, groundPath, file.getInputStream(),file.getSize(), historyUploadSize);
//修改已存文件片数
redisService.set(CommonConstant.uploadChunkNum+identifier,String.valueOf(chunkNumber),cacheTime);
if (chunkNumber == totalChunks){
//最后一片，返回结果
return groundPath;
}
return "第："+chunkNumber+"上传成功";
}else {
logger.error("第："+chunkNumber+"上传失败，原因：当前上传");
throw new SystemException(ResultEnum.ERR.getCode(),"第："+chunkNumber+"上传失败");
}
}
}catch (Exception e){
e.printStackTrace();
logger.error("第："+chunkNumber+"上传失败，原因：{}",e);
throw new SystemException(ResultEnum.ERR.getCode(),"第："+chunkNumber+"上传失败");
}
}
}
4、CommonConstant类
public class CommonConstant {
private final static String uploading="Uploading:";
private final static String file=uploading+"file:";
public final static String uploadChunkNum=file+"chunkNum:";
public final static String fastDfsPath=file+"fastDfsPath:";
public final static String DEFAULT_GROUP = "group1";
}
