How to Implement File Upload in Spring Boot: Step-by-Step Guide
This tutorial explains how to add file‑upload functionality to a Spring Boot application, covering project setup, template engine configuration, HTML upload page creation, controller implementation, property settings, testing steps, and where to find the full source code.
File upload is a common scenario in web applications, such as avatar uploads or Excel data import, requiring an upload step before further processing.
This article walks through implementing file upload in a Spring Boot project.
Step 1: Create a basic Spring Boot project
Initialize a Spring Boot application (see quick start guide if needed).
Step 2: Add template engine dependency
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>You may also use other template engines such as Freemarker.
Step 3: Create upload page
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8" />
<title>File Upload Page</title>
</head>
<body>
<h1>File Upload Page</h1>
<form method="post" action="/upload" enctype="multipart/form-data">
Choose file: <input type="file" name="file"><br>
<hr>
<input type="submit" value="Submit">
</form>
</body>
</html>Step 4: Implement UploadController
@Slf4j
@Controller
public class UploadController {
@Value("${file.upload.path}")
private String path;
@GetMapping("/")
public String uploadPage() {
return "upload";
}
@PostMapping("/upload")
@ResponseBody
public String create(@RequestPart MultipartFile file) throws IOException {
String fileName = file.getOriginalFilename();
String filePath = path + fileName;
File dest = new File(filePath);
Files.copy(file.getInputStream(), dest.toPath());
return "Upload file success : " + dest.getAbsolutePath();
}
}Key elements:
Member variable path injected from file.upload.path configuration.
GET / returns the upload page.
POST /upload saves the uploaded file to the configured directory.
Note: This demo shows the basic flow; real applications should handle filename conflicts, distributed storage, etc.
Step 5: Configure application.properties
spring.servlet.multipart.max-file-size=2MB
spring.servlet.multipart.max-request-size=2MB
file.upload.path=/Users/didi/The first two properties limit upload size; the last defines the directory for saved files.
Testing
1. Run the Spring Boot application and visit http://localhost:8080 to see the upload page.
2. Choose a file ≤2 MB and click “Submit”. If successful, a page showing the file path appears.
You can verify the file was saved at the printed path.
Code Repository
Examples are available in the chapter4-3 directory of the following repositories:
GitHub: https://github.com/dyc87112/SpringBoot-Learning/
Gitee: https://gitee.com/didispace/SpringBoot-Learning/
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Programmer DD
A tinkering programmer and author of "Spring Cloud Microservices in Action"
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