Foreword: Here is a summary of the common file upload and download functions in the current SpringBoot project. There are three common download methods and one upload method. Here is a note to share.
Table of contents
3.1. Use the download method provided by the Spring framework
3.2. Download as a stream through IOUtils
Five, the complete code of the tool class
1. pom dependency
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>Two, yml configuration file
# Spring配置
spring:
# 文件上传
servlet:
multipart:
# 单个文件大小
max-file-size: 10MB
# 设置总上传的文件大小
max-request-size: 20MB
server:
port: 9090
3. File download
3.1. Use the download method provided by the Spring framework
key code:
/**
* 使用Spring框架自带的下载方式
* @param filePath
* @param fileName
* @return
*/
public ResponseEntity<Resource> download(String filePath,String fileName) throws Exception {
fileName = URLEncoder.encode(fileName,"UTF-8");
File file = new File(filePath);
if(!file.exists()){
throw new Exception("文件不存在");
}
return ResponseEntity.ok().header(HttpHeaders.CONTENT_DISPOSITION,
"attachment; filename=" + fileName ).body(new FileSystemResource(filePath));
}request layer:
@RestController
@RequestMapping("/file")
public class FileController {
@Autowired
private FileUtil fileUtil;
@GetMapping("/spring/download")
public ResponseEntity<Resource> download() throws Exception {
String filePath = "D:\\1.jpg";
String fileName = "Spring框架下载.jpg";
return fileUtil.download(filePath,fileName);
}
}Browser input: http://localhost:9090/file/spring/download
Download completed.
3.2. Download as a stream through IOUtils
key code:
/**
* 通过IOUtils以流的形式下载
* @param filePath
* @param fileName
* @param response
*/
public void download(String filePath , String fileName, HttpServletResponse response) throws Exception {
fileName = URLEncoder.encode(fileName,"UTF-8");
File file=new File(filePath);
if(!file.exists()){
throw new Exception("文件不存在");
}
response.setHeader("Content-disposition","attachment;filename="+ fileName);
FileInputStream fileInputStream = new FileInputStream(file);
IOUtils.copy(fileInputStream,response.getOutputStream());
response.flushBuffer();
fileInputStream.close();
}request layer:
@RestController
@RequestMapping("/file")
public class FileController {
@Autowired
private FileUtil fileUtil;
@GetMapping("/io/download")
public void ioDownload(HttpServletResponse response) throws Exception {
String filePath = "D:\\1.jpg";
String fileName = "IO下载.jpg";
fileUtil.download(filePath,fileName,response);
}
}Browser access: http://localhost:9090/file/io/download
download successful.
3.3. Download while reading
key code:
/**
* 原始的方法，下载一些小文件，边读边下载的
* @param filePath
* @param fileName
* @param response
* @throws Exception
*/
public void downloadTinyFile(String filePath,String fileName, HttpServletResponse response)throws Exception{
File file = new File(filePath);
fileName = URLEncoder.encode(fileName, "UTF-8");
if(!file.exists()){
throw new Exception("文件不存在");
}
FileInputStream in = new FileInputStream(file);
response.setHeader("Content-Disposition", "attachment;filename="+fileName);
OutputStream out = response.getOutputStream();
byte[] b = new byte[1024];
int len = 0;
while((len = in.read(b))!=-1){
out.write(b, 0, len);
}
out.flush();
out.close();
in.close();
}request layer:
@RestController
@RequestMapping("/file")
public class FileController {
@Autowired
private FileUtil fileUtil;
@GetMapping("/tiny/download")
public void tinyDownload(HttpServletResponse response) throws Exception {
String filePath = "D:\\1.jpg";
String fileName = "tiny下载.jpg";
fileUtil.downloadTinyFile(filePath,fileName,response);
}
}
Browser input: http://localhost:9090/file/tiny/download
download successful.
4. File upload
Upload files using MultipartFile
/**
* 上传文件
* @param multipartFile
* @param storagePath
* @return
* @throws Exception
*/
public String upload(MultipartFile multipartFile, String storagePath) throws Exception{
if (multipartFile.isEmpty()) {
throw new Exception("文件不能为空！");
}
String originalFilename = multipartFile.getOriginalFilename();
String newFileName = UUID.randomUUID()+"_"+originalFilename;
String filePath = storagePath+newFileName;
File file = new File(filePath);
if (!file.getParentFile().exists()) {
file.getParentFile().mkdirs();
}
multipartFile.transferTo(file);
return filePath;
}request layer:
@RestController
@RequestMapping("/file")
public class FileController {
@Autowired
private FileUtil fileUtil;
@PostMapping("/multipart/upload")
public String download(MultipartFile file) throws Exception {
String storagePath = "D:\\";
return fileUtil.upload(file,storagePath);
}
}Test with the postman tool:
Find this file on the D drive.
Five, the complete code of the tool class
package com.example.file.utils;
import org.apache.tomcat.util.http.fileupload.IOUtils;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.Resource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.util.UUID;
/**
* 文件工具类
* @author HTT
*/
@Component
public class FileUtil {
/**
* 使用Spring框架自带的下载方式
* @param filePath
* @param fileName
* @return
*/
public ResponseEntity<Resource> download(String filePath,String fileName) throws Exception {
fileName = URLEncoder.encode(fileName,"UTF-8");
File file = new File(filePath);
if(!file.exists()){
throw new Exception("文件不存在");
}
return ResponseEntity.ok().header(HttpHeaders.CONTENT_DISPOSITION,
"attachment; filename=" + fileName ).body(new FileSystemResource(filePath));
}
/**
* 通过IOUtils以流的形式下载
* @param filePath
* @param fileName
* @param response
*/
public void download(String filePath , String fileName, HttpServletResponse response) throws Exception {
fileName = URLEncoder.encode(fileName,"UTF-8");
File file=new File(filePath);
if(!file.exists()){
throw new Exception("文件不存在");
}
response.setHeader("Content-disposition","attachment;filename="+ fileName);
FileInputStream fileInputStream = new FileInputStream(file);
IOUtils.copy(fileInputStream,response.getOutputStream());
response.flushBuffer();
fileInputStream.close();
}
/**
* 原始的方法，下载一些小文件，边读边下载的
* @param filePath
* @param fileName
* @param response
* @throws Exception
*/
public void downloadTinyFile(String filePath,String fileName, HttpServletResponse response)throws Exception{
File file = new File(filePath);
fileName = URLEncoder.encode(fileName, "UTF-8");
if(!file.exists()){
throw new Exception("文件不存在");
}
FileInputStream in = new FileInputStream(file);
response.setHeader("Content-Disposition", "attachment;filename="+fileName);
OutputStream out = response.getOutputStream();
byte[] b = new byte[1024];
int len = 0;
while((len = in.read(b))!=-1){
out.write(b, 0, len);
}
out.flush();
out.close();
in.close();
}
/**
* 上传文件
* @param multipartFile
* @param storagePath
* @return
* @throws Exception
*/
public String upload(MultipartFile multipartFile, String storagePath) throws Exception{
if (multipartFile.isEmpty()) {
throw new Exception("文件不能为空！");
}
String originalFilename = multipartFile.getOriginalFilename();
String newFileName = UUID.randomUUID()+"_"+originalFilename;
String filePath = storagePath+newFileName;
File file = new File(filePath);
if (!file.getParentFile().exists()) {
file.getParentFile().mkdirs();
}
multipartFile.transferTo(file);
return filePath;
}
}
6. Gitee source code
Code cloud address: SpringBoot implements file upload and download
7. Summary
The above are the notes for SpringBoot to implement file upload and download functions, which can be copied and used with one click.