使用SpringBoot實現文件的下載

上一篇博客：使用SpringBoot實現文件的上傳

已經實現了文件的上傳，所以緊接着就是下載

首先還是html頁面的簡單設計

 

<form class="form-signin" th:action="@{/employee/File/download}" method="post">
 <p><h1>下載文件</h1></p>
 <p><h2>1.png</h2></p>
 <p><input type="submit" value="下載"/></p>
 <p style="color: red" th:text="${result}" th:if="${not #strings.isEmpty(result)}"></p>
</form>

待下載文件名為1.png

 

然后寫controller

package com.manager.controller.FileController;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

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

@Controller
public class FileDownloadController {

 @PostMapping("/employee/File/download")
 public String testDownload( HttpServletResponse response ,Model model) {
 //待下載文件名
 String fileName = "1.png";
 //設置為png格式的文件
 response.setHeader("content-type", "image/png");
 response.setContentType("application/octet-stream");
 response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
 byte[] buff = new byte[1024];
 //創建緩沖輸入流
 BufferedInputStream bis = null;
 OutputStream outputStream = null;

 try {
 outputStream = response.getOutputStream();

 //這個路徑為待下載文件的路徑
 bis = new BufferedInputStream(new FileInputStream(new File("D:/upload/" + fileName )));
 int read = bis.read(buff);

 //通過while循環寫入到指定了的文件夾中
 while (read != -1) {
 outputStream.write(buff, 0, buff.length);
 outputStream.flush();
 read = bis.read(buff);
 }
 } catch ( IOException e ) {
 e.printStackTrace();
 //出現異常返回給頁面失敗的信息
 model.addAttribute("result","下載失敗");
 } finally {
 if (bis != null) {
 try {
 bis.close();
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 if (outputStream != null) {
 try {
 outputStream.close();
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 }
 //成功后返回成功信息
 model.addAttribute("result","下載成功");
 return "employee/EmployeeDownloadFile";
 }
}

訪問頁面測試

 

 選擇下載路徑，點擊保存

 

 成功下載!