springboot notes - file upload

Use Spring Boot and Thymeleaf upload files

Spring Boot MultipartFile usage characteristics to receive and process uploaded files, the present exemplary Thymeleaf used to process the front page.

Quick Start:

1, add dependencies

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

2, application.properties configuration information

# The maximum supported file 
spring.servlet.multipart.max -file-size = 100MB 
# file requests a maximum limit 
spring.servlet.multipart.max -request-size = 100MB

# In addition to the above configuration too, common configuration information is as follows:
spring.servlet.multipart.enabled = to true, whether to support the multipart upload files
spring.servlet.multipart.file-size-threshold = 0, support files written to disk
spring.servlet. multipart.location =, the temporary directory to upload files
spring.servlet.multipart.max-file-size = 10Mb, supports maximum file size
spring.servlet.multipart.max-request-sizee = 10Mb, maximum support request size
spring.servlet. multipart.resolve-lazily = false, whether lazy load support multipart upload files

3, start class

@SpringBootApplication
public class FileUploadWebApplication {

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

    //Tomcat large file upload connection reset
    @Bean
    public TomcatServletWebServerFactory tomcatEmbedded() {
        TomcatServletWebServerFactory tomcat = new TomcatServletWebServerFactory();
        tomcat.addConnectorCustomizers((TomcatConnectorCustomizer) connector -> {
            if ((connector.getProtocolHandler() instanceof AbstractHttp11Protocol<?>)) {
                //-1 means unlimited
                ((AbstractHttp11Protocol<?>) connector.getProtocolHandler()).setMaxSwallowSize(-1);
            }
        });
        return tomcat;
    }
}

TomcatServletWebServerFactory () method is to solve the problems uploading files larger than 10M connection reset

4, simple front page:

　　Single file upload page upload.html:

    <!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>

　　Multiple file upload page uploadMore.html:

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

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

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

    </body>
    </html>

Upload results page: uploadStatus.html

<!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>

5, background upload control class

@Controller
 public  class UploadController { 
    
    // file storage directory 
    Private String upload_path = "E: TEMP // //" ; 

    // jump upload page 
    @RequestMapping ( "/" )
     public String index () {
         return "Upload" ; 
    } 
    
    
    @GetMapping ( "/ more" )
     public String uploadMore () {
         return "uploadMore" ; 
    } 
    
    // plurality of file upload 
    @RequestMapping ( "/ uploadMore" )
     public String moreFileUpload (@RequestParam ( "file") MultipartFile[] files,RedirectAttributes redirectAttrs) {
        if(files.length ==0) {
            redirectAttrs.addFlashAttribute("message", "Please select a file to upload");
            return "redirect:uploadStatus";
        }
        
        for(MultipartFile file :files) {
            try {
                byte[] bytes = file.getBytes();
                Path path = Paths.get(UPLOAD_PATH+file.getOriginalFilename());
                Files.write(path, bytes);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        redirectAttrs.addFlashAttribute("message",
                "You successfully uploaded all files");
        return "redirect:/uploadStatus";
    }
    
    
    //单个文件上传
    @PostMapping("/upload")
    public String singleFileUpload(@RequestParam("file") MultipartFile file,RedirectAttributes redirectAttrs) {
        if(file.isEmpty()) {
            redirectAttrs.addFlashAttribute("message", "Please select a file to upload");
            return "redirect:uploadStatus";
        }
        
        try {
            byte[] bytes = file.getBytes();
            Path path = Paths.get(UPLOAD_PATH+file.getOriginalFilename());
            Files.write(path, bytes);
            redirectAttrs.addFlashAttribute("message",
                        "You successfully uploaded '" + file.getOriginalFilename() + "'");
        } catch (IOException e) {
            e.printStackTrace();
        }
        
        return "redirect:/uploadStatus";
    }
    
    //跳转结果页面
    @RequestMapping("/uploadStatus")
    public String uploadStatus() {
        return "uploadStatus";
    }
}

6, run startup class: FileUploadWebApplication

In the browser, go to:

　　Multiple file upload:

OK, uploaded successfully.

springboot notes - file upload

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