SpringBoot实现文件上传下载

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spring:
  servlet:
    multipart:
      enabled: true # 表示是否开启文件上传支持，默认为 true
      file-size-threshold: 0 # 表示文件写入磁盘的阀值，默认为 0
      location: # 表示上传文件的临时保存位置
      max-file-size: 1MB # 表示上传的单个文件的最大大小，默认为 1MB
      max-request-size: 10MB # 表示多文件上传时文件的总大小，默认为 10MB

file:
  upload:
    url: E:/test # 上传路径

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multipart.max-file-size

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spring.http.multipart.max-file-size

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spring.servlet.multipart.max-file-size

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package com.zmjwdzjl.controller;

import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
import java.io.*;

@RestController
@RequestMapping("file")
@Slf4j
public class FileController {
    
    @Value("${file.upload.url}")
    private String uploadFilePath;

    @PostMapping("/upload")
    public String httpUpload(@RequestParam("files") MultipartFile files[]) {
        JSONObject object = new JSONObject();
        for(int i=0;i<files.length;i++) {
            // getOriginalFilename方法获取文件名(带后缀)，getName方法获取文件名(不带后缀)
            String fileName = files[i].getOriginalFilename();
            File dest = new File(uploadFilePath +'/'+ fileName);
            // 判断文件所在目录是否存在，如果不存在就创建对应的目录
            if (!dest.getParentFile().exists()) {
                dest.getParentFile().mkdirs();
            }
            try {
                // 将文件存放到对应的目录下，如果上传重复的文件不会报错，后上传的文件会覆盖已上传的文件
                files[i].transferTo(dest);
            } catch (Exception e) {
                log.error("{}",e);
                object.put("success",2);
                object.put("result","程序错误，请重新上传");
                return object.toString();
            }
        }
        object.put("success",1);
        object.put("result","文件上传成功");
        return object.toString();
    }
}

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@RequestMapping("/download")
public String fileDownLoad(HttpServletResponse response, @RequestParam("fileName") String fileName) {
    File file = new File(uploadFilePath +'/'+ fileName);
    if(!file.exists()) {
        return "下载文件不存在";
    }
    response.reset();
    response.setContentType("application/octet-stream");
    response.setCharacterEncoding("utf-8");
    response.setContentLength((int) file.length());
    response.setHeader("Content-Disposition", "attachment;filename=" + fileName );
    try(BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file))) {
        byte[] buff = new byte[1024];
        OutputStream os  = response.getOutputStream();
        int i = 0;
        while ((i = bis.read(buff)) != -1) {
            os.write(buff, 0, i);
            os.flush();
        }
    } catch (IOException e) {
        log.error("{}",e);
        return "下载失败";
    }
    return "下载成功";
}