工作中上传文件是常见的场景之一，最典型的情况就是上传头像等，上传文档。自己上传文件中遇到的坑,自己已经填了,现在把它写下来,方便提醒自己,我使用的是Spring Boot 上传文件
Pom
主要引入了web和thymeleaf启动器
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| <!-- web start-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- web end-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
|
yml
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| spring:
servlet:
multipart:
max-file-size: 10MB # 最大支持文件大小
max-request-size: 10MB # 最大支持请求大小
#enabled: true #默认支持文件上传.
# file-size-threshold: #支持文件写入磁盘.
#location: #上传文件的临时目录
|
controller
UploadController
UploadController首页的显示
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| @Controller
public class UploadController {
@GetMapping("/")
public String index() {
return "upload";
}
}
|
FileController
FileController文件上传,下载请求
文件上传
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| /**
* @author: 三月三
* @description: 单个文件上传
* @param: [file]
* @return: java.lang.String
*/
@RequestMapping(value = "/upload")
public String upload(HttpServletRequest request, @RequestParam("file") MultipartFile file, Model model) {
// 测试MultipartFile接口的各个方法
System.out.println("文件类型ContentType=" + file.getContentType());
System.out.println("文件组件名称Name=" + file.getName());
System.out.println("文件原名称OriginalFileName=" + file.getOriginalFilename());
System.out.println("文件大小Size=" + file.getSize()/1024 + "KB");
try {
if (file.isEmpty()) {
return "文件为空";
}
// 获取文件名
String fileName = file.getOriginalFilename();
log.info("上传的文件名为：" + fileName);
// 获取文件的后缀名
String suffixName = fileName.substring(fileName.lastIndexOf("."));
log.info("文件的后缀名为：" + suffixName);
// 获取文件相对类路径
//String filePath = request.getServletContext().getRealPath("/");
//文件绝对路径,项目中一般使用相对类路径,即使文件变更路径也会跟着变
String filePath = request.getServletContext().getRealPath("G:\\dev_workspace\\springboot-learning-examples\\springboot-13-fileupload\\src\\main\\resources\\static");
System.out.println("path = " + filePath);
//构造一个路径
String newImg = UUID.randomUUID()+suffixName;
String path = filePath + newImg;
log.info("构造路径"+path);
File dest = new File(path);
// 检测是否存在目录
if (!dest.getParentFile().exists()) {
dest.getParentFile().mkdirs();// 新建文件夹
}
file.transferTo(dest);// 文件写入
model.addAttribute("msg","<font color=\"green\">上传成功</font>");
model.addAttribute("img",newImg);
return "upload";
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
model.addAttribute("msg","<font color=\"green\">上传失败</font>");
return "upload";
}
|
多文件上传
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| /**
* @author: 三月三
* @description: 多个文件上传
* @param: [request]
* @return: java.lang.String
*/
@PostMapping("/batch")
public String handleFileUpload(Model model,HttpServletRequest request) {
List<MultipartFile> files = ((MultipartHttpServletRequest) request).getFiles("file");
MultipartFile file = null;
BufferedOutputStream stream = null;
for (int i = 0; i < files.size(); ++i) {
file = files.get(i);
//文件绝对路径,项目中一般使用相对类路径,即使文件变更路径也会跟着变
String filePath = request.getServletContext().getRealPath("G:\\dev_workspace\\springboot-learning-examples\\springboot-13-fileupload\\src\\main\\resources\\static");
if (!file.isEmpty()) {
try {
byte[] bytes = file.getBytes();
stream = new BufferedOutputStream(new FileOutputStream(
new File(filePath + file.getOriginalFilename())));//设置文件路径及名字
stream.write(bytes);// 写入
stream.close();
} catch (Exception e) {
stream = null;
model.addAttribute("msg", "第 " + i + " 个文件上传失败 ==> "
+ e.getMessage());
return "upload";
}
} else {
model.addAttribute("msg","第 " + i
+ " 个文件上传失败因为文件为空");
return "upload";
}
}
model.addAttribute("msg","上传成功");
return "upload";
}
|
文件下载
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| /**
* @author: 三月三
* @description: 文件下载
* @param: [model, request, response, fileName]
* @return: java.lang.String
*/
@PostMapping("/download")
public String downloadFile(Model model,HttpServletRequest request, HttpServletResponse response,String fileName) {
if (fileName != null) {
//设置文件路径 真实环境是存放在数据库中的
// String filePath = request.getServletContext().getRealPath("/");
//文件绝对路径,项目中一般使用相对类路径,即使文件变更路径也会跟着变
String filePath = request.getServletContext().getRealPath("G:\\dev_workspace\\springboot-learning-examples\\springboot-13-fileupload\\src\\main\\resources\\static");
File file = new File(filePath);
if (file.exists()) {
response.setContentType("application/force-download");// 设置强制下载不打开
response.addHeader("Content-Disposition", "attachment;fileName=" + fileName);// 设置文件名
byte[] buffer = new byte[1024];
FileInputStream fis = null;
BufferedInputStream bis = null;
try {
fis = new FileInputStream(file);
bis = new BufferedInputStream(fis);
// 创建输出对象
OutputStream os = response.getOutputStream();
int i = bis.read(buffer);
while (i != -1) {
os.write(buffer, 0, i);
i = bis.read(buffer);
}
model.addAttribute("msg","<font color=\"green\">下载成功</font>");
return "upload";
} catch (Exception e) {
e.printStackTrace();
} finally {
if (bis != null) {
try {
bis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (fis != null) {
try {
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
model.addAttribute("msg","<font color=\"red\">下载失败</font>");
return "upload";
}
|
页面
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| <!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<body>
<h1>Spring Boot file upload example</h1>
<p>单文件上传</p>
<form action="upload" method="POST" enctype="multipart/form-data">
文件：<input type="file" name="file"/>
<input type="submit"/>
</form>
<span th:if="${msg!=null}" th:utext="${msg}"></span>
<div th:if="${img!=null}">
<img th:src="${img}">
<p>文件下载</p>
<form action="download" method="post">
<input type="hidden" th:value="${img}" name="fileName"/>
<input type="submit" value="下载文件"/>
</form>
</div>
<p>多文件上传</p>
<form method="POST" enctype="multipart/form-data" action="batch">
<p>文件1：<input type="file" name="file"/></p>
<p>文件2：<input type="file" name="file"/></p>
<p><input type="submit" value="上传"/></p>
</form>
</body>
</html>
|
BUG
- 文件上传路径问题
- 文件下载的路径问题
解决:
String filePath = request.getServletContext().getRealPath("/");获取的是tomcat目录下webapps下的目录及类路径(class文件存放的路径),因为我使用的是SpringBoot项目,而SringBoot项目内嵌了tomcat,路径为C:\Users\L15096000421\AppData\Local\Temp\tomcat-docbase.2191751665660359817.8080\的一个临时目录- 还是使用
String filePath = request.getServletContext().getRealPath("/")做为下载的路径去下载文件,后台报错没有权限,使用绝对路径下载,及使用绝对路径上传
