Pom依赖

<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.wxd</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>2.1.0.RELEASE</version>
    </parent>

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

    <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>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

    </dependencies>

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

</project>

后台逻辑

UploadController

package com.wxd.controller;

import lombok.extern.slf4j.Slf4j;
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.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

@Controller
@Slf4j
public class UploadController {
    /**
     * 上传文件保存路径
     */
    private static String UPLOADED_FOLDER = "upload" + File.separator;

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

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

    @PostMapping("/upload")
    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 {
            //获取文件并保存
            byte[] bytes = file.getBytes();
            Path dir = Paths.get(UPLOADED_FOLDER);
            Path path = Paths.get(UPLOADED_FOLDER + file.getOriginalFilename());
            if (!Files.exists(dir)) {
                Files.createDirectories(dir);
            }
            Files.write(path, bytes);
            redirectAttributes.addFlashAttribute("message", "You successfully uploaded '" + file.getOriginalFilename() + "'");

        } catch (IOException e) {
            redirectAttributes.addFlashAttribute("message", "Server throw IOException");
            log.error(e.getMessage(), e);
        }
        return "redirect:/uploadStatus";
    }

}

全局异常处理

package com.wxd.controller;

import lombok.extern.slf4j.Slf4j;
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
@Slf4j
public class GlobalExceptionHandler {

    /**
     * 文件上传全局异常捕获
     *
     * @param e
     * @param redirectAttributes
     * @return
     */
    @ExceptionHandler(MultipartException.class)
    public String handleError(MultipartException e, RedirectAttributes redirectAttributes) {
        log.error(e.getMessage(), e);
        redirectAttributes.addFlashAttribute("message", e.getCause().getMessage());
        return "redirect:/uploadStatus";
    }
}

前端逻辑

文件上传页面

路径：templates\upload.html

<!DOCTYPE html>
<html lang="en">
<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>

上传成功后提示页面

路径：templates\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>

application.yml 配置

#文件上传相关配置
pring:
  servlet:
    multipart:
      enabled: true
      max-file-size: 100MB
      max-request-size: 100MB

启动应用后上传文件

开始上传

上传成功