This article shows you how to upload a file in Spring Boot web application.

Tools used :

  1. Spring Boot 1.4.3.RELEASE
  2. Spring 4.3.5.RELEASE
  3. Thymeleaf
  4. Maven
  5. Embedded Tomcat 8.5.6

1. Project Structure

A standard project structure.

spring-boot-file-upload-example-directory

2. Project Dependency

Spring boot dependencies, no need extra library for file upload.

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
         http://maven.apache.org/maven-v4_0_0.xsd">
         <modelVersion>4.0.0</modelVersion>

    <groupId>com.mkyong</groupId>
    <artifactId>spring-boot-file-upload</artifactId>
    <packaging>jar</packaging>
    <version>1.0</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.3.RELEASE</version>
    </parent>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

        <!-- hot swapping, disable cache for template, enable live reload -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <!-- Package as an executable jar/war -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

3. File Upload Example

Spring boot file upload, zero configuration.

3.1 In the Controller, maps the uploaded file to MultipartFile

UploadController.java

package com.mkyong.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

@Controller
public class UploadController {

    //Save the uploaded file to this folder
    private static String UPLOADED_FOLDER = "F://temp//";

    @GetMapping("/")
    public String index() {
        return "upload";
    }

    @PostMapping("/upload") // //new annotation since 4.3
    public String singleFileUpload(@RequestParam("file") MultipartFile file,
                                   RedirectAttributes redirectAttributes) {

        if (file.isEmpty()) {
            redirectAttributes.addFlashAttribute("message", "Please select a file to upload");
            return "redirect:uploadStatus";
        }

        try {

            // Get the file and save it somewhere
            byte[] bytes = file.getBytes();
            Path path = Paths.get(UPLOADED_FOLDER + file.getOriginalFilename());
            Files.write(path, bytes);

            redirectAttributes.addFlashAttribute("message",
                    "You successfully uploaded '" + file.getOriginalFilename() + "'");

        } catch (IOException e) {
            e.printStackTrace();
        }

        return "redirect:/uploadStatus";
    }

    @GetMapping("/uploadStatus")
    public String uploadStatus() {
        return "uploadStatus";
    }

}

3.2 In thymeleaf, just some normal HTML file tags.

upload.jsp

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<body>

<h1>Spring Boot file upload example</h1>

<form method="POST" action="/upload" enctype="multipart/form-data">
    <input type="file" name="file" /><br/><br/>
    <input type="submit" value="Submit" />
</form>

</body>
</html>

3.3 Another page for upload status

uploadStatus.jsp

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<body>

<h1>Spring Boot - Upload Status</h1>

<div th:if="${message}">
    <h2 th:text="${message}"/>
</div>

</body>
</html>

4. Max upload size exceeded

To handle the max upload size exceeded exception, declares a @ControllerAdvice and catch the MultipartException

GlobalExceptionHandler.java

package com.mkyong.controller;

import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.multipart.MultipartException;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;

@ControllerAdvice
public class GlobalExceptionHandler {

    //https://jira.spring.io/browse/SPR-14651
    //Spring 4.3.5 supports RedirectAttributes
    @ExceptionHandler(MultipartException.class)
    public String handleError1(MultipartException e, RedirectAttributes redirectAttributes) {

        redirectAttributes.addFlashAttribute("message", e.getCause().getMessage());
        return "redirect:/uploadStatus";

    }

    /* Spring < 4.3.5
	@ExceptionHandler(MultipartException.class)
    public String handleError2(MultipartException e) {

        return "redirect:/errorPage";

    }*/

}

5. Tomcat Connection Reset

If you deployed to Tomcat, configure the maxSwallowSize to avoid this Tomcat connection reset issue. For embedded Tomcat, declares a TomcatEmbeddedServletContainerFactory like the following :

SpringBootWebApplication.java

package com.mkyong;

import org.apache.coyote.http11.AbstractHttp11Protocol;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.embedded.tomcat.TomcatConnectorCustomizer;
import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class SpringBootWebApplication {

    private int maxUploadSizeInMb = 10 * 1024 * 1024; // 10 MB

    public static void main(String[] args) throws Exception {
        SpringApplication.run(SpringBootWebApplication.class, args);
    }

    //Tomcat large file upload connection reset
    //http://www.mkyong.com/spring/spring-file-upload-and-connection-reset-issue/
    @Bean
    public TomcatEmbeddedServletContainerFactory tomcatEmbedded() {

        TomcatEmbeddedServletContainerFactory tomcat = new TomcatEmbeddedServletContainerFactory();

        tomcat.addConnectorCustomizers((TomcatConnectorCustomizer) connector -> {
            if ((connector.getProtocolHandler() instanceof AbstractHttp11Protocol<?>)) {
                //-1 means unlimited
                ((AbstractHttp11Protocol<?>) connector.getProtocolHandler()).setMaxSwallowSize(-1);
            }
        });

        return tomcat;

    }

}

6. Multipart File Size

By default, Spring Boot max file upload size is 1MB, you can configure the values via following application properties :

application.properties

#http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#common-application-properties
#search multipart
spring.http.multipart.max-file-size=10MB
spring.http.multipart.max-request-size=10MB

7. DEMO

Start Spring Boot with the default embedded Tomcat mvn spring-boot:run.

Terminal

$ mvn spring-boot:run
 .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.4.3.RELEASE)
 
2017-01-21 07:48:53 INFO  com.mkyong.SpringBootWebApplication - Starting SpringBootWebApplication on MKYONG-WIN10 with PID 2384 (E:\spring-boot-file-upload\target\classes started by mkyong in E:\spring-boot-file-upload)
2017-01-21 07:48:53 DEBUG com.mkyong.SpringBootWebApplication - Running with Spring Boot v1.4.3.RELEASE, Spring v4.3.5.RELEASE
2017-01-21 07:48:53 INFO  com.mkyong.SpringBootWebApplication - No active profile set, falling back to default profiles: default
2017-01-21 07:48:55 INFO  com.mkyong.SpringBootWebApplication - Started SpringBootWebApplication in 2.54 seconds (JVM running for 2.924)

7.1 Access http://localhost:8080/

spring-boot-file-upload-example

7.2 Select a file and upload it.

spring-boot-file-upload-example-2

7.3 Select a file larger than 10mb, you will visit this page.

spring-boot-file-upload-example-3

8. Download Source Code

References

  1. Spring Boot common application properties
  2. Spring MVC file upload example
  3. Spring @ExceptionHandler and RedirectAttributes
  4. Spring Boot Hello World Example – Thymeleaf