6 Spring Boot文件上传

文件上传是项目开发中的常见操作。一般分为如下几种解决方案

• 直接上传到应用服务器
• 上传到阿里云、七牛云等OSS服务器
• 图片转成Base64后传到服务器

本例以第一种为例，实现将本地图片上传到服务器指定路径的基础功能
新建一个module，命名为file-upload，勾选web、Thymeleaf依赖

pom.xml

       
            org.springframework.boot
            spring-boot-starter-thymeleaf
        
        
            org.springframework.boot
            spring-boot-starter-web
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        

在resources的templates目录下建两个html文件，如图所示的项目结构

image.png

application.properties配置一下上传参数

spring.servlet.multipart.max-file-size=100MB
spring.servlet.multipart.max-request-size=100MB

编写UploadController，映射上传请求

package com.springboot.fileupload.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 {
    private static String UPLOADED_FOLDER = "E:/temp/";

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

    @PostMapping("/upload")
    public String singleFileUpload(@RequestParam("file") MultipartFile file,
                                   RedirectAttributes redirectAttributes) {
        if (file.isEmpty()) {
            redirectAttributes.addFlashAttribute("message", "请选择一个文件");
            return "redirect:upload_status";
        }

        try {
            byte[] bytes = file.getBytes();
            Path path = Paths.get(UPLOADED_FOLDER + file.getOriginalFilename());
            Files.write(path, bytes);
            redirectAttributes.addFlashAttribute("message",
                    "文件成功上传!" + file.getOriginalFilename());
        } catch (IOException e) {
            e.printStackTrace();
        }

        return "redirect:/upload_status";
    }

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

upload.html文件

Spring Boot 文件上传示例

    
    

    

    

upload_status.html文件

Spring Boot - 文件上传状态

    

运行启动主类，http://localhost:8080定向到了upload.html页面

上传页面

选择一个本地文件，点击提交，将文件提交到了服务器指定目录，页面跳转到upload_status.html，提示上传成功

upload_status

image.png

如果要把上传的路径跟着项目，如在static目录下的upload文件夹，则需要更改UploadController代码

import org.springframework.stereotype.Controller;
import org.springframework.util.ResourceUtils;
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.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

@Controller
public class UploadController {

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

    @PostMapping("/upload")
    public String singleFileUpload(@RequestParam("file") MultipartFile srcFile,
                                   RedirectAttributes redirectAttributes) {
        if (srcFile.isEmpty()) {
            redirectAttributes.addFlashAttribute("message", "请选择一个文件");
            return "redirect:upload_status";
        }
        try {
            File destFile = new File(ResourceUtils.getURL("classpath:").getPath());
            if (!destFile.exists()) {
                destFile = new File("");
            }
            System.out.println("file path:" + destFile.getAbsolutePath());
            File upload = new File(destFile.getAbsolutePath(), "static/");
            if (!upload.exists()) {
                upload.mkdirs();
            }
            System.out.println("upload url:" + upload.getAbsolutePath());
            Path path = Paths.get(upload.getAbsolutePath() + "/" + srcFile.getOriginalFilename());
            byte[] bytes = srcFile.getBytes();
            Files.write(path, bytes);
            redirectAttributes.addFlashAttribute("message",
                    "文件成功上传!" + srcFile.getOriginalFilename());
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "redirect:/upload_status";
    }

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

会将文件上传到target/classes/static目录下，如图

image.png