Ví dụ Upload file với Spring Boot

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
      
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.o7planning</groupId>
    <artifactId>SpringBootFileUpload</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>SpringBootFileUpload</name>
    <description>Spring Boot + File Upload Example</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

package org.o7planning.sbfileupload;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringBootFileUploadApplication {

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

spring.servlet.multipart.max-file-size=5MB
spring.servlet.multipart.max-request-size=5MB

package org.o7planning.sbfileupload.form;

import org.springframework.web.multipart.MultipartFile;

public class MyUploadForm {

    private String description;

    // Upload files.
    private MultipartFile[] fileDatas;

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public MultipartFile[] getFileDatas() {
        return fileDatas;
    }

    public void setFileDatas(MultipartFile[] fileDatas) {
        this.fileDatas = fileDatas;
    }

}

package org.o7planning.sbfileupload.controller;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.o7planning.sbfileupload.form.MyUploadForm;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.multipart.MultipartFile;

@Controller
public class MyFileUploadController {

	@RequestMapping(value = "/")
	public String homePage() {

		return "index";
	}

	// GET: Hiển thị trang form upload
	@RequestMapping(value = "/uploadOneFile", method = RequestMethod.GET)
	public String uploadOneFileHandler(Model model) {

		MyUploadForm myUploadForm = new MyUploadForm();
		model.addAttribute("myUploadForm", myUploadForm);

		return "uploadOneFile";
	}

	// POST: Sử lý Upload
	@RequestMapping(value = "/uploadOneFile", method = RequestMethod.POST)
	public String uploadOneFileHandlerPOST(HttpServletRequest request, //
			Model model, //
			@ModelAttribute("myUploadForm") MyUploadForm myUploadForm) {

		return this.doUpload(request, model, myUploadForm);

	}

	// GET: Hiển thị trang form upload
	@RequestMapping(value = "/uploadMultiFile", method = RequestMethod.GET)
	public String uploadMultiFileHandler(Model model) {

		MyUploadForm myUploadForm = new MyUploadForm();
		model.addAttribute("myUploadForm", myUploadForm);

		return "uploadMultiFile";
	}

	// POST: Sử lý Upload
	@RequestMapping(value = "/uploadMultiFile", method = RequestMethod.POST)
	public String uploadMultiFileHandlerPOST(HttpServletRequest request, //
			Model model, //
			@ModelAttribute("myUploadForm") MyUploadForm myUploadForm) {

		return this.doUpload(request, model, myUploadForm);

	}

	private String doUpload(HttpServletRequest request, Model model, //
			MyUploadForm myUploadForm) {

		String description = myUploadForm.getDescription();
		System.out.println("Description: " + description);

		// Thư mục gốc upload file.
		String uploadRootPath = request.getServletContext().getRealPath("upload");
		System.out.println("uploadRootPath=" + uploadRootPath);

		File uploadRootDir = new File(uploadRootPath);
		// Tạo thư mục gốc upload nếu nó không tồn tại.
		if (!uploadRootDir.exists()) {
			uploadRootDir.mkdirs();
		}
		MultipartFile[] fileDatas = myUploadForm.getFileDatas();
		// 
		List<File> uploadedFiles = new ArrayList<File>();
		List<String> failedFiles = new ArrayList<String>();

		for (MultipartFile fileData : fileDatas) {

			// Tên file gốc tại Client.
			String name = fileData.getOriginalFilename();
			System.out.println("Client File Name = " + name);

			if (name != null && name.length() > 0) {
				try {
					// Tạo file tại Server.
					File serverFile = new File(uploadRootDir.getAbsolutePath() + File.separator + name);

					BufferedOutputStream stream = new BufferedOutputStream(new FileOutputStream(serverFile));
					stream.write(fileData.getBytes());
					stream.close();
					// 
					uploadedFiles.add(serverFile);
					System.out.println("Write file: " + serverFile);
				} catch (Exception e) {
					System.out.println("Error Write file: " + name);
					failedFiles.add(name);
				}
			}
		}
		model.addAttribute("description", description);
		model.addAttribute("uploadedFiles", uploadedFiles);
		model.addAttribute("failedFiles", failedFiles);
		return "uploadResult";
	}

}

<div  xmlns:th="http://www.thymeleaf.org"
   style="border:1px solid #ccc;padding:5px;">
 
   <a th:href="@{/uploadOneFile}">Upload One File</a>
   
   &nbsp;|&nbsp;
   
   <a th:href="@{/uploadMultiFile}">Upload Multi File</a>
   
   
 </div>

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

   <head>
      <meta charset="UTF-8">
      <title>Spring Boot File Upload Example</title>
   </head>
   
   <body>
      <th:block th:include="/_menu"></th:block>
      
      <h3>Spring Boot File Upload Example</h3>
      
      <ul>
        <li><a th:href="@{/uploadOneFile}">Upload One File Example</a></li>
        <li><a th:href="@{/uploadMultiFile}">Upload Multiple Files Example</a></li>
      </ul>
      
   </body>
</html>

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

   <head>
      <meta charset="UTF-8">
      <title>Upload One File</title>
   </head>
  
   <body>
      <th:block th:include="/_menu"></th:block>
      
      <h3>Upload One File:</h3>
      
      <!-- MyUploadForm -->
      
      <form th:object="${myUploadForm}" method="POST"
         action="" enctype="multipart/form-data">
         Description:
         <br>
         <input th:field="*{description}" style="width:300px;"/>                
         <br/><br/>  
         File to upload: <input th:field="*{fileDatas}" type="file"/>
         <br />  
         <input type="submit" value="Upload">
      </form>
      
   </body>
</html>

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

   <head>
      <meta charset="UTF-8">
      <title>Upload Multi File</title>
   </head>
   
   <body>
      <th:block th:include="/_menu"></th:block>
      <h3>Upload Multiple File:</h3>
      
      <!-- MyUploadForm -->
      <form th:object="${myUploadForm}" method="POST"
         action="" enctype="multipart/form-data">
         Description:
         <br>
         <input th:field="*{description}" style="width:300px;"/>                
         <br/><br/>                 
         File to upload (1): <input th:field="*{fileDatas}" type="file"/><br />      
         File to upload (2): <input th:field="*{fileDatas}" type="file"/><br />    
         File to upload (3): <input th:field="*{fileDatas}" type="file"/><br />    
         File to upload (4): <input th:field="*{fileDatas}" type="file"/><br />    
         File to upload (5): <input th:field="*{fileDatas}" type="file"/><br />    
         <input type="submit" value="Upload">
      </form>
      
   </body>
</html>

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
   <head>
      <meta charset="UTF-8">
      <title>Upload Result</title>
   </head>
   
   <body>
      <th:block th:include="/_menu"></th:block>
      
      Description: <span th:utext="${description}"></span>
      <br/>
      <h3>Uploaded Files:</h3>
      
      <ul th:each="file : ${uploadedFiles}">
         <li th:utext="${file}"></li>  
      </ul>      
      
      <h3>Failed:</h3>
      <ul th:each="file : ${failedFiles}">
         <li style="color:red;" th:utext="${file}"></li>  
      </ul>
      
   </body>
   
</html>