SpringBoot2 | 第二十篇：使用SpringBoot上传文件

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​ 在工作中用的都是工具类，对 IO流 的使用也忘得差不多了，写个 Demo 来复习一下。spring boot 的文件上传与 spring mvc 的文件上传基本一致，只需注意一些配置即可。

[TOC]

环境/版本一览：

  • 开发工具：Intellij IDEA 2018.2.2
  • springboot： 2.0.6.RELEASE
  • jdk：1.8.0_171
  • maven：3.3.9
  • spring-boot-starter-thymeleaf： 2.0.6.RELEASE

1、pom.xml

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<dependencies>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.8</version>
    </dependency>
    <!-- 引入 Thymeleaf 模板引擎依赖 -->
    <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>

2、application.yml

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spring:
  thymeleaf:
    cache: false
  servlet:
    multipart:
      # 设置单个文件最大值
      max-file-size: 10MB
      # 设置总上传数据最大值
      max-request-size: 10MB

# 文件上传路径
upload:
  path: E:/upload/fatal/
#  path: /usr/local/upload/fatal/

3、templates

upload.html

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<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>上传文件</title>
</head>
<body>
    <h1>Spring Boot file upload example</h1>

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

uploadStatus.html

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<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>上传状态</title>
</head>
<body>

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

    <div th:if="${message}">
        <h2 th:text="${message}"/>
    </div>
    
    <div th:if="${files}">
        <h3 th:text="${files}"/>
</div>
</body>
</html>

4、FileUtil

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package com.fatal.utils;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Arrays;

/**
 * 文件工具类
 * @author: Fatal
 * @date: 2019/7/21 0021 12:46
 */
@Slf4j
@Component
public class FileUtil {

    @Value("${upload.path}")
    private String uploadPath;

    /**
     * 上传一个或多个文件
     */
    public void uploadFiles(MultipartFile[] files) {
        Arrays.stream(files)
                .forEach(this::uploadByFiles);
//                .forEach(this::uploadByFileStream);
//                .forEach(this::uploadByMultipartFile);
    }

    /**
     * @param file 文件
     * @param filePath 文件保存路径
     * @param filename  文件名（包括后缀）
     * private void uploadByxxx(MultipartFile file)
     * 注意：这三个方法都一样，如果图片名字格式相同，则会覆盖
     */

    /**
     * FileStreams
     */
    private void uploadByFileStream(MultipartFile file) {
        FileInputStream in = null;
        FileOutputStream out = null;
        try {
            long start = System.currentTimeMillis();
            String filename = file.getOriginalFilename();
            in = (FileInputStream)file.getInputStream();
            File directory = new File(uploadPath);
            initDirectory(directory);
            out = new FileOutputStream(uploadPath + filename);
            byte[] bytes = new byte[1024];
            int len = 0;
            while ((len = in.read(bytes)) != -1) {
                out.write(bytes, 0, len);
            }
            long end = System.currentTimeMillis();
            log.info("【文件 {} 上传耗时】 [{}]", filename, end - start);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
            if (in!= null) {
                try {
                    in.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
        }
    }


    /**
     * nio
     */
    private void uploadByFiles(MultipartFile file) {
        try {
            long start = System.currentTimeMillis();
            String filename = file.getOriginalFilename();
            byte[] bytes = new byte[1024];
            Path path = Paths.get(uploadPath + filename);
            File directory = new File(uploadPath);
            initDirectory(directory);
            Files.write(path, bytes);
            long end = System.currentTimeMillis();
            log.info("【文件 {} 上传耗时】 [{}]", filename, end - start);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * SpringMVC 封装的上传文件的方法 MultipartFile.transferTo(File dest)
     */
    private void uploadByMultipartFile(MultipartFile file) {
        try {
            long start = System.currentTimeMillis();
            String filename = file.getOriginalFilename();
            File directory = new File(uploadPath);
            initDirectory(directory);
            file.transferTo(new File(uploadPath + filename));
            long end = System.currentTimeMillis();
            log.info("【文件 {} 上传耗时】 [{}]", filename, end - start);
        } catch (IOException e){
            e.printStackTrace();
        }
    }

    /**
     * 初始化文件夹
     * @param directory
     */
    private void initDirectory(File directory) {
        // 判断文件是否存在，不存在则新建一个
        if (!directory.exists()) {
            boolean mkdirs = directory.mkdirs();
            if (!mkdirs) {
                log.error("【文件上传】 文件夹创建失败 -[{}]", uploadPath);
            }
        }
    }

}

5、handler

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package com.fatal.handler;

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

/**
 * 全局异常处理器
 * @author: Fatal
 * @date: 2018/10/26 0026 11:19
 */
@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(RuntimeException.class)
    public String handler(RuntimeException e, RedirectAttributes redirectAttributes) {
        redirectAttributes.addFlashAttribute("message", e.getMessage());
        return "redirect:/uploadStatus";
    }

}

6、controller

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package com.fatal.controller;

import com.fatal.utils.FileUtil;
import org.springframework.beans.factory.annotation.Autowired;
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.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

/**
 * 文件上传控制器
 * @author: Fatal
 * @date: 2018/10/25 0025 19:47
 */
@Controller
public class FileController {

    @Autowired
    private FileUtil fileUtil;

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

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

    @PostMapping("/upload")
    public String fileUpload(@RequestParam("file") MultipartFile[] files,
                                   RedirectAttributes redirectAttributes) {
        if (files.length == 0) {
            redirectAttributes.addFlashAttribute("message", "Select at least one file to upload");
            return "redirect:uploadStatus";
        }

        try {
            fileUtil.uploadFiles(files);
            List<String> fileNames = Arrays.stream(files)
                    .map(MultipartFile::getOriginalFilename)
                    .collect(Collectors.toList());
            redirectAttributes.addFlashAttribute("message", "Successful file uploaded");
            redirectAttributes.addFlashAttribute("files", fileNames);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("uploaded fail");
        }

        return "redirect:/uploadStatus";
    }

}

7、测试

启动项目

访问 http://localhost:8080

选择上传文件

1563704716326

点击submit

1563704776526

看看控制台

1563704880753

看看文件是否上传成功

1563704817867

参考链接

Spring Boot(十七)：使用 Spring Boot 上传文件

总结

SpringBoot的知识已经有前辈在我们之前探索了。比较喜欢的博主有：唐亚峰 | Battcn、方志朋的专栏、程序猿DD、纯洁的微笑。对这门技术感兴趣的可以去他们的博客逛逛。谢谢他们的分享~~

以上文章是我用来学习的Demo，都是基于 SpringBoot2.x 版本。

源码地址: https://github.com/ynfatal/springboot2-learning/tree/master/chapter20

学习 纯洁的微笑 前辈的经验