SpringBoot2.x实现文件上传与下载

1，配置pom文件

    4.0.0

    com.itpengwei
    springboot-test
    0.0.1-SNAPSHOT
    jar

    springboot-test
    Demo project for Spring Boot

    
        org.springframework.boot
        spring-boot-starter-parent
        2.0.3.RELEASE
         
    

    
        UTF-8
        UTF-8
        1.8
    

    
        
            org.springframework.boot
            spring-boot-starter-web
        
        
        
            org.springframework.boot
            spring-boot-starter-thymeleaf
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

2，配置文件(application.yml)

server:
  port: 8080
spring:
  thymeleaf:
    cache: false
  servlet:
    multipart:
      max-file-size: 5Mb
      max-request-size: 10Mb

3,Controller

package com.itpengwei.springboottest.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.*;

/**
 * 文件上传,下载类
 */
@Controller
public class FileUploadController {
    /**
     * 文件上传
     *
     * @param file
     * @return
     */
    @PostMapping(value = "/fileUpload")
    @ResponseBody
    public String fileUpload(@RequestParam("fileName") MultipartFile file) {
        if (file.isEmpty()) {
            return "请选择一个文上传";
        }
        String filename = file.getOriginalFilename();
        long fileSize = file.getSize();
        System.out.println("文件名称" + filename + "-------文件大小" + fileSize);
        String path = "F:/test";
        File dest = new File(path + "/" + filename);
        if (!dest.getParentFile().exists()) {
            //父目录不存在就创建一个
            dest.getParentFile().mkdir();
        }
        //保存文件
        try {
            file.transferTo(dest);
            return "文件上传成功";
        } catch (IOException e) {
            e.printStackTrace();
            return "文件上传失败";
        }
    }

    /**
     * 文件下载
     *
     * @param response
     * @return
     */
    @RequestMapping(value = "/fileDownload")
    @ResponseBody
    public String download(HttpServletResponse response) {
        String fileName = "Cloud总结.docx";
        String filepath = "F:/test";
        File file = new File(filepath + "/" + fileName);
        byte[] buff = new byte[1024];
        BufferedInputStream bis = null;
        OutputStream os = null;
        try {
            os = response.getOutputStream();
            bis = new BufferedInputStream(new FileInputStream(file));
            int i = bis.read(buff);
            while (i != -1) {
                os.write(buff, 0, buff.length);
                os.flush();
                i = bis.read(buff);
            }
        } catch (IOException e) {
            e.printStackTrace();
            return "文件上传失败";
        } finally {
            if (bis != null) {
                try {
                    bis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return "文件上传成功";
    }
}

4，启动项目，就实现了文件上传与下载