SpringBoot文件上传下载

项目中经常会有上传和下载的需求，这篇文章简述一下springboot项目中实现简单的上传和下载。

新建springboot项目，前台页面使用的thymeleaf模板，其余的没有特别的配置，pom代码如下：

    4.0.0

    com.dalaoyang
    springboot_upload_download
    0.0.1-SNAPSHOT
    jar

    springboot_upload_download
    springboot_upload_download

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

    
        UTF-8
        UTF-8
        1.8
    

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

        
            org.springframework.boot
            spring-boot-devtools
            runtime
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        

        
            net.sourceforge.nekohtml
            nekohtml
            1.9.15
        
    

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

前台页面index.html，其中包含单个上传，下载，批量上传。

    
    


单文件上传

    文件：
    


文件下载
下载文件

多文件上传

    
文件1：
    
文件2：
    

IndexController只是用来页面的跳转

package com.dalaoyang.Controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author dalaoyang
 * @Description
 * @project springboot_learn
 * @package com.dalaoyang.Controller
 * @email [email protected]
 * @date 2018/4/9
 */
@Controller
public class IndexController {

    @RequestMapping("/")
    public String index()
    {
        return "index";
    }
}

最后是本文的重点，FileController，其中包含单个上传，单个下载，批量上传对应的方法。需要注意下载功能写的是对应我电脑里面固定位置的文件，仅供大家来参考。以下是代码：

package com.dalaoyang.Controller;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.List;


/**
 * @author dalaoyang
 * @Description
 * @project springboot_learn
 * @package com.dalaoyang.Controller
 * @email [email protected]
 * @date 2018/4/9
 */
@RestController
public class FileController {
    private static final Logger log = LoggerFactory.getLogger(FileController.class);

    @RequestMapping(value = "/upload")
    public String upload(@RequestParam("file") MultipartFile file) {
        try {
            if (file.isEmpty()) {
                return "文件为空";
            }
            // 获取文件名
            String fileName = file.getOriginalFilename();
            log.info("上传的文件名为：" + fileName);
            // 获取文件的后缀名
            String suffixName = fileName.substring(fileName.lastIndexOf("."));
            log.info("文件的后缀名为：" + suffixName);
            // 设置文件存储路径
            String filePath = "/Users/dalaoyang/Downloads/";
            String path = filePath + fileName;
            File dest = new File(path);
            // 检测是否存在目录
            if (!dest.getParentFile().exists()) {
                dest.getParentFile().mkdirs();// 新建文件夹
            }
            file.transferTo(dest);// 文件写入
            return "上传成功";
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "上传失败";
    }

    @PostMapping("/batch")
    public String handleFileUpload(HttpServletRequest request) {
        List files = ((MultipartHttpServletRequest) request).getFiles("file");
        MultipartFile file = null;
        BufferedOutputStream stream = null;
        for (int i = 0; i < files.size(); ++i) {
            file = files.get(i);
            String filePath = "/Users/dalaoyang/Downloads/";
            if (!file.isEmpty()) {
                try {
                    byte[] bytes = file.getBytes();
                    stream = new BufferedOutputStream(new FileOutputStream(
                            new File(filePath + file.getOriginalFilename())));//设置文件路径及名字
                    stream.write(bytes);// 写入
                    stream.close();
                } catch (Exception e) {
                    stream = null;
                    return "第 " + i + " 个文件上传失败 ==> "
                            + e.getMessage();
                }
            } else {
                return "第 " + i
                        + " 个文件上传失败因为文件为空";
            }
        }
        return "上传成功";
    }

    @GetMapping("/download")
    public String downloadFile(HttpServletRequest request, HttpServletResponse response) {
        String fileName = "dalaoyang.jpeg";// 文件名
        if (fileName != null) {
            //设置文件路径
            File file = new File("/Users/dalaoyang/Documents/dalaoyang.jpeg");
            //File file = new File(realPath , fileName);
            if (file.exists()) {
                response.setContentType("application/force-download");// 设置强制下载不打开
                response.addHeader("Content-Disposition", "attachment;fileName=" + fileName);// 设置文件名
                byte[] buffer = new byte[1024];
                FileInputStream fis = null;
                BufferedInputStream bis = null;
                try {
                    fis = new FileInputStream(file);
                    bis = new BufferedInputStream(fis);
                    OutputStream os = response.getOutputStream();
                    int i = bis.read(buffer);
                    while (i != -1) {
                        os.write(buffer, 0, i);
                        i = bis.read(buffer);
                    }
                    return "下载成功";
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (bis != null) {
                        try {
                            bis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if (fis != null) {
                        try {
                            fis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
        return "下载失败";
    }
}

源码下载 ：大老杨码云

个人网站：https://dalaoyang.cn