SpringBoot 实现文件上传下载

1. 创建boot工程，添加依赖

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

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

2. 配置文件

server.port=8091
server.servlet.context-path=/

# 上传文件总的最大值
spring.servlet.multipart.max-request-size=10MB
# 单个文件的最大值
spring.servlet.multipart.max-file-size=10MB

3. 单文件上传案例

package com.javaboy.file.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.IOException;

/**
 * @author: gaoyang
 * @date: 2021-03-23 09:28
 * @description: 文件上传下载
 */
@Slf4j
@RestController
@RequestMapping("/file")
public class FileController {

    @PostMapping("/upload")
    public String upload(@RequestParam(name = "file") MultipartFile file) {
        if (file.isEmpty()) {
            return "上传失败，请选择文件";
        }

        // 获取文件名
        String filename = file.getOriginalFilename();
        // 获取文件后缀
        String suffix = filename.substring(filename.lastIndexOf(".") + 1).toLowerCase();

        // 如果目录不存在则创建
        File fullDir = new File("D:/file/test/");
        if (!fullDir.exists()) {
            fullDir.mkdirs();
        }

        // 保存文件
        String path = filename + "." + suffix;
        String fullPath = fullDir + path;
        File dest = new File(fullPath);
        try {
            file.transferTo(dest);
            log.info("上传成功");
            return "上传成功";
        } catch (IOException e) {
            log.error(e.getMessage());
            e.printStackTrace();
        }

        return "上传失败";
    }

}

4. 多文件上传案例