springboot-下载文件(多种文件)

原创已于 2023-03-12 20:22:26 修改 · 868 阅读

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于 2023-03-12 20:21:16 首次发布

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文章展示了在SpringBoot项目中使用Thymeleaf模板引擎，结合Hutool库实现文件下载的四种不同方式，包括使用ServletUtil工具类、POST请求下载、ResponseEntity下载以及ByteArrayResource下载。同时，文章提到了配置文件中设定的文件存储路径以及前端HTML页面的下载链接示例。

导入依赖

 <!-- 添加web起步依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
 
<!-- Thymeleaf模板起步依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
 
<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.1</version>
</dependency>

<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.4.2</version>
</dependency>

yml配置文件配置的被下载文件的路径

spring:
  upload-path: F:/file/upload/

前端

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>下载文件</title>
</head>
<body>

<h2>下载文件1</h2>
<a th:href="@{/download1/1.png}">1.png</a>


<h2>下载文件2</h2><br>
<form th:action="@{/download2}" method="post">
    下载文件：<input th:type="text" name="filename"><br>
    <input th:type="submit" value="下载"><br>
</form>

<h2>下载文件3</h2>
<a th:href="@{/download3?filename=1.png}">1.png</a>
</body>

<h2>下载文件4</h2>
<a th:href="@{/download4?filename=1.png}">1.png</a>
</body>

</html>

后端-controller

package com.demo.controller;

import cn.hutool.extra.servlet.ServletUtil;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.io.FileUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.ByteArrayResource;
import org.springframework.core.io.InputStreamResource;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

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


@Slf4j
@Controller
public class DownloadFileController {

    @Value("${spring.upload-path}")
    private String resourcePath;

    @GetMapping("toDownload")
    public String toDownload() {
        return "download";
    }

    /**
     * 使用 hutool 下载
     * @param filename
     * @param response
     */
    @GetMapping("/download1/{filename}")
    public void downloadfile1(@PathVariable("filename") String filename, HttpServletResponse response) {

        String filepath = resourcePath + filename;

        response.setCharacterEncoding("UTF-8");

        ServletUtil.write(response,new File(filepath));

    }

    @PostMapping("/download2")
    public void downloadFile2(@RequestParam("filename") String filename, HttpServletResponse response) {

        String filepath = resourcePath + File.separator + filename;
        log.debug("filepath is " + filepath);

        //设置文件格式
        response.reset();
        response.setHeader("content-type", "image/png");
        response.setContentType("application/octet-stream; charset=utf-8");
        response.setHeader("Content-Disposition", "attachment; filename=" + filename);

        byte[] buff = new byte[1024];

        //创建缓冲输入流
        BufferedInputStream bis = null;
        OutputStream os = null;

        try {
            os = response.getOutputStream();

            bis = new BufferedInputStream(new FileInputStream(filepath));

            int read = bis.read(buff);

            while (read != -1) {
                os.write(buff, 0, buff.length);
                os.flush();
                read = bis.read(buff);
            }
        } catch (IOException e) {
            e.printStackTrace();

        } finally {

            if (bis != null) {
                try {
                    bis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            if (os != null) {
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }

    }

    @GetMapping("download3")
    public ResponseEntity<InputStreamResource> downloadFile3(String filename) throws FileNotFoundException {

        String filepath = resourcePath + filename;

        InputStreamResource isr = new InputStreamResource(new FileInputStream(filepath));

        return ResponseEntity.ok()
                .contentType(MediaType.APPLICATION_OCTET_STREAM)
                .header("Content-disposition", "attachment; filename=" + filename)
                .body(isr);
    }


    @GetMapping("/download4")
    public ResponseEntity<ByteArrayResource> downloadFile4(@RequestParam("filename") String filename) throws IOException {

        String filepath = resourcePath + filename;

        byte[] bytes = FileUtils.readFileToByteArray(new File(filepath));

        ByteArrayResource bar = new ByteArrayResource(bytes);

        return ResponseEntity.ok()
                .contentType(MediaType.APPLICATION_OCTET_STREAM)
                .header("Content-disposition", "attachment; filename=" + filename)
                .body(bar);
    }

}