在平时的业务场景中，避免不了，要搭建文件上传服务器，作为公共服务。一般情况，只做了单个文件的上传，实际业务场景中，却发现单个文件上传，并不能满足一些业务需求，因此我们需要解决如何写一个同时上传多个文件的接口，并返回可下载的文件地址；

废话不多讲，不再从头建立一个 Spring boot 项目，如果不知道的话，请直接前往官网查看实例。

下面我们以上传图片为例，示例相对简单，仅供参考：

1 后端上传图片接口逻辑

UploadController.java
package com.zz.controllers.fileUpload;
import com.zz.Application;
import com.zz.model.Response;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.web.server.LocalServerPort;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import java.io.*;
import java.net.Inet4Address;
import java.net.InetAddress;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.UUID;
import static com.zz.config.ConfigConstants.getFileDir;
@RestController
@Configuration
public class UploadController {
 private static final Logger log = LoggerFactory.getLogger(Application.class);
 @Value("${server.port}")
 private String port;
 //获取当前IP地址
 public String getIp() {
  InetAddress localhost = null;
  try {
   localhost = Inet4Address.getLocalHost();
  } catch (Exception e) {
   log.error(e.getMessage());
   e.printStackTrace();
  }
  return localhost.getHostAddress();
 }
 @PostMapping(value = "/upload", consumes = {"multipart/form-data"})
 public Response upload(@RequestParam("file") MultipartFile[] files, Response response) {
  log.info("上传多个文件");
  StringBuilder builder = new StringBuilder();
  // file address
  String fileAddress ="http://"+ getIp()+ ":" + port + File.separator;
  ArrayList<String> imgUrls = new ArrayList<String>();
  try {
   for (int i = 0; i < files.length; i++) {
    // old file name
    String fileName = files[i].getOriginalFilename();
    // new filename
    String generateFileName = UUID.randomUUID().toString().replaceAll("-", "") + fileName.substring(fileName.lastIndexOf("."));
    // store filename
    String distFileAddress = fileAddress + generateFileName;
    builder.append(distFileAddress+",");
    imgUrls.add(distFileAddress);
    // generate file to disk
    files[i].transferTo(new File(getFileDir() + generateFileName));
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
  response.setMsg("success");
  log.info(builder.toString());
  response.setData(imgUrls);
  return response;
 }
}

相对于单个文件的接收，我们这里直接接受多个 file 对象，然后遍历生成每个对应的地址。

其中：

getFileDir 设置存放图片的地址，我选择存在项目外的其他地方

com.zz.config.ConfigConstants.getFileDir
package com.zz.config;
public class ConfigConstants {
 public static String fileDir;
 public static String getFileDir() {
  fileDir = "/Users/wz/projects/blog/uploadFile/";
  return fileDir;
 }
}