SpringBoot/SpringMVC文件下载方式

本篇文章引用外网博客代码,共描述SpringMVC下三种文件下载方式,本人测试在SpringBoot(2.0以上版本)正常使用.

引用博客,强烈推荐https://www.boraji.com.

package com.boraji.tutorial.spring.controller;

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import javax.servlet.http.HttpServletResponse;

import org.springframework.core.io.ByteArrayResource;

import org.springframework.core.io.InputStreamResource;

import org.springframework.http.HttpHeaders;

import org.springframework.http.MediaType;

import org.springframework.http.ResponseEntity;

import org.springframework.stereotype.Controller;

import org.springframework.ui.Model;

import org.springframework.web.bind.annotation.GetMapping;

/**

 * @author imssbora

 */

@Controller

public class FileDownloadController {

   private static final String FILE_PATH = "D:/e-Books/jsp_tutorial.pdf";

   @GetMapping("/")

   public String fileUploadForm(Model model) {

      return "fileDownloadView";

   }

   // Using ResponseEntity<InputStreamResource>

   @GetMapping("/download1")

   public ResponseEntity<InputStreamResource> downloadFile1() throws IOException {

      File file = new File(FILE_PATH);

      InputStreamResource resource = new InputStreamResource(new FileInputStream(file));

      return ResponseEntity.ok()

            .header(HttpHeaders.CONTENT_DISPOSITION,

                  "attachment;filename=" + file.getName())

            .contentType(MediaType.APPLICATION_PDF).contentLength(file.length())

            .body(resource);

   }

   // Using ResponseEntity<ByteArrayResource>

   @GetMapping("/download2")

   public ResponseEntity<ByteArrayResource> downloadFile2() throws IOException {

      Path path = Paths.get(FILE_PATH);

      byte[] data = Files.readAllBytes(path);

      ByteArrayResource resource = new ByteArrayResource(data);

      return ResponseEntity.ok()

            .header(HttpHeaders.CONTENT_DISPOSITION,

                  "attachment;filename=" + path.getFileName().toString())

            .contentType(MediaType.APPLICATION_PDF).contentLength(data.length)

            .body(resource);

   }

   // Using HttpServletResponse

   @GetMapping("/download3")

   public void downloadFile3(HttpServletResponse resonse) throws IOException {

      File file = new File(FILE_PATH);

      // 示例中使用的是pdf，实际的content-type需要根据上传文件时的content-type进行确定(最长可达255字节)

      resonse.setContentType("application/pdf");

      resonse.setHeader("Content-Disposition", "attachment;filename=" + file.getName());

      BufferedInputStream inStrem = new BufferedInputStream(new FileInputStream(file));

      BufferedOutputStream outStream = new BufferedOutputStream(resonse.getOutputStream());

      byte[] buffer = new byte[1024];

      int bytesRead = 0;

      while ((bytesRead = inStrem.read(buffer)) != -1) {

        outStream.write(buffer, 0, bytesRead);

      }

      outStream.flush();

      inStrem.close();

   }

}

ResponseEntity表示HTTP响应,包含body,header以及status code.

ResponseEntity可以在RestTemplate 以及@Controller中使用.