基于SpringBoot的文件上传

文件上传方式：1.直接上传到应用服务器（速度，容量） 2.上传到oss(内容存储服务器)（阿里云，七牛云）3.前端将图片转出Base64编码上传（小容量的上传）

第一种：先键一个新的模块upload

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然后finish,建立包和三个类

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UploadController类

package com.springboot.upload.controller;
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;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;
//上传文件控制器
//直接上传到服务器
@Controller
public class UploadController {
//指定一个临时路径作为上传目录
//private static String UPLOAD_FOLDER = "C:\Users\Liuyu\Desktop\UPLOAD\";
//遇到http://localhost:8080，则跳转至upload.html页面
@GetMapping("/")
public String index() {
return "upload";
}
@PostMapping("upload")
public String fileUpload(@RequestParam("file")MultipartFile srcFile, RedirectAttributes redirectAttributes) {
//前端没有选择文件，srcFile为空
if(srcFile.isEmpty()) {
redirectAttributes.addFlashAttribute("message", "请选择一个文件");
return "redirect:upload_status";
}
//选择了文件，开始上传操作
try {
//构建上传目标路径，找到了项目的target的classes目录
File destFile = new File(ResourceUtils.getURL("classpath:").getPath());
if(!destFile.exists()) {
destFile = new File("");
}
//输出目标文件的绝对路径
System.out.println("file path:"+destFile.getAbsolutePath());
//拼接子路径
SimpleDateFormat sf_ = new SimpleDateFormat("yyyyMMddHHmmss");
String times = sf_.format(new Date());
File upload = new File(destFile.getAbsolutePath(), "picture/"+times);
//若目标文件夹不存在，则创建
if(!upload.exists()) {
upload.mkdirs();
}
System.out.println("完整的上传路径："+upload.getAbsolutePath()+"/"+srcFile);
//根据srcFile大小，准备一个字节数组
byte[] bytes = srcFile.getBytes();
//拼接上传路径
//Path path = Paths.get(UPLOAD_FOLDER + srcFile.getOriginalFilename());
//通过项目路径，拼接上传路径
Path path = Paths.get(upload.getAbsolutePath()+"/"+srcFile.getOriginalFilename());
//** 开始将源文件写入目标地址
Files.write(path, bytes);
String uuid = UUID.randomUUID().toString().replaceAll("-", "");
// 获得文件原始名称
String fileName = srcFile.getOriginalFilename();
// 获得文件后缀名称
String suffixName = fileName.substring(fileName.lastIndexOf(".") + 1).toLowerCase();
// 生成最新的uuid文件名称
String newFileName = uuid + "."+ suffixName;
redirectAttributes.addFlashAttribute("message", "文件上传成功"+newFileName);
} catch (IOException e) {
e.printStackTrace();
}
return "redirect:upload_status";
}
//匹配upload_status页面
@GetMapping("upload_status")
public String uploadStatusPage() {
return "upload_status";
}
}

upload.html

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>SpringBoot文件上传页面</title>
</head>
<body>
<form method="post" action="/upload" enctype="multipart/form-data">
<input type="file" name="file">
<input type="submit" value="上传">
</form>
</body>
</html>

upload_status.html

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>文件上传状态显示</title>
</head>
<body>
<h2>SpringBoot的文件上传状态</h2>
<div th:if=" ${message}"> <h2 th:text="$ {message}"/>
</div>
</body>
</html>