写在前面：
本文只关注快速实现功能，写的比较简化，因此适合有一些 SpringBoot 基础的小伙伴~~~
配置文件和配置类
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.quan</groupId>
<artifactId>upload</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>upload</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
application.yml
spring:
#thymeleaf
thymeleaf:
cache: false # 默认开启缓存，开发环境建议关闭
enabled: true # 启用MVC Thymeleaf视图分辨率
encoding: UTF-8 # 模板编码
mode: HTML5 # 应用于模板的模板模式
prefix: classpath:/templates/ #模板前缀，在此路径下存放模板
suffix: .html #模板后缀
servlet:
content-type: text/html # servlet 格式
UploadConfig.java
@Configuration
public class UploadConfig {
@Bean
public MultipartConfigElement multipartConfigElement() {
MultipartConfigFactory factory = new MultipartConfigFactory();
//允许上传的文件最大值
factory.setMaxFileSize(DataSize.parse("50MB"));
/// 设置总上传数据总大小
factory.setMaxRequestSize(DataSize.parse("50MB"));
return factory.createMultipartConfig();
}
}
注：我试过在yml配置文件中修改上传文件大小限制，但是不生效，如果你的yml中关于文件上传大小的配置生效，这个配置类大可不必。
Controller
UploadController.java
@Controller
public class UploadController {
private static final Logger LOGGER = LoggerFactory.getLogger(UploadController.class);
// 上传下载指定文件夹
private static final String FILEPATH = "C:/Users/admin/Desktop/upload/";
@GetMapping("/")
public String index() {
return "index";
}
@PostMapping("/upload")
@ResponseBody
public String upload(@RequestParam("file") MultipartFile file) {
if (file.isEmpty()) {
return "上传失败，请选择文件";
}
// 获取上传的文件名称
String fileName = file.getOriginalFilename();
// 上传文件保存路径
File dest = new File(FILEPATH + fileName);
try {
file.transferTo(dest);
LOGGER.info("上传成功");
return "上传成功";
} catch (IOException e) {
LOGGER.error(e.toString(), e);
}
return "上传失败！";
}
@PostMapping("/multiUpload")
@ResponseBody
public String multiUpload(HttpServletRequest request) {
List<MultipartFile> files = ((MultipartHttpServletRequest) request).getFiles("file");
String filePath = "C:/Users/admin/Desktop/upload/";
for (int i = 0; i < files.size(); i++) {
MultipartFile file = files.get(i);
if (file.isEmpty()) {
return "上传第" + (i++) + "个文件失败";
}
String fileName = file.getOriginalFilename();
File dest = new File(filePath + fileName);
try {
file.transferTo(dest);
LOGGER.info("第" + (i + 1) + "个文件上传成功");
} catch (IOException e) {
LOGGER.error(e.toString(), e);
return "上传第" + (i++) + "个文件失败";
}
}
return "上传成功";
}
@PostMapping("/downFile")
@ResponseBody
public String downFile(String fileName, HttpServletRequest request, HttpServletResponse response) throws Exception {
//获取输入流对象
FileInputStream fis = new FileInputStream(new File(FILEPATH, fileName));
//获取文件后缀
String extendFileName = fileName.substring(fileName.lastIndexOf("."));
//动态设置相应类型，根据前台文件类型设置响应类型
response.setContentType(request.getSession().getServletContext().getMimeType(extendFileName));
//设置响应头，attachment表示以附件形式下载，inline表示在线打开
response.setHeader("content-disposition", "attachment;fileName=" + URLEncoder.encode(fileName, "UTF-8"));
//获取输出流对象
ServletOutputStream os = response.getOutputStream();
//下载文件，使用spring框架中的FileCopyUtils工具
FileCopyUtils.copy(fis, os);
return "下载成功！";
}
}
注：UploadController 中也包括对下载的处理。
页面
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<h2>单文件上传</h2>
<form method="post" action="/upload" enctype="multipart/form-data">
<input required type="file" name="file"><br>
<input required type="submit" value="提交">
</form>
<br>
<br>
<h2>多个文件上传</h2>
<form method="post" action="/multiUpload" enctype="multipart/form-data">
<input required type="file" name="file"><br>
<input required type="file" name="file"><br>
<input required type="file" name="file"><br>
<input required type="submit" value="提交">
</form>
<br>
<br>
<h2>下载文件</h2>
<form method="post" action="/downFile">
<!--两种方式都可实现 但是下载的文件必须是 controller里指定文件夹中的-->
<input required type="file" name="fileName"><br>
<!--<input type="text" name="fileName"><br>-->
<input required type="submit" value="下载">
</form>
<br>
<br>
</body>
</html>
测试
测试会发现我们成功实现了文件的上传和下载！
ps：如有疑问可以联系 QQ:1540752331