springboot 文件上传、下载
1. 搭建一个springboot的开发环境
以下是springboot的pow.xml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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.wyl</groupId>
<artifactId>SpringBootFile</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>SpringBootFile</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.7</java.version>
</properties>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.3.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- thymeleaf模板插件 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
</dependencies>
</project>
2、application.properties文件中取消模板文件缓存
spring.thymeleaf.cache=false
3、编写模板文件
1>file.html
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org" xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity3">
<head>
<meta charset="UTF-8" />
<title>Insert title here</title>
</head>
<body>
<h1 th:inlines="text">文件上传</h1>
<form action="fileUpload" method="post" enctype="multipart/form-data">
<p>选择文件: <input type="file" name="fileName"/></p>
<p><input type="submit" value="提交"/></p>
</form>
</body>
</html>
2>multifile.html
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org"
xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity3">
<head>
<meta charset="UTF-8" />
<title>Insert title here</title>
</head>
<body>
<h1 th:inlines="text">文件上传</h1>
<form action="multifileUpload" method="post" enctype="multipart/form-data" >
<p>选择文件1: <input type="file" name="fileName"/></p>
<p>选择文件2: <input type="file" name="fileName"/></p>
<p>选择文件3: <input type="file" name="fileName"/></p>
<p><input type="submit" value="提交"/></p>
</form>
</body>
</html>
4.编写Controller
@Controller
public class FileUploadController {
/*
* 获取file.html页面
*/
@RequestMapping("file")
public String file(){
return "/file";
}
/**
* 实现文件上传
* */
@RequestMapping("fileUpload")
@ResponseBody
public String fileUpload(@RequestParam("fileName") MultipartFile file){
if(file.isEmpty()){
return "false";
}
String fileName = file.getOriginalFilename();
int size = (int) file.getSize();
System.out.println(fileName + "-->" + size);
String path = "F:/test" ;
File dest = new File(path + "/" + fileName);
if(!dest.getParentFile().exists()){ //判断文件父目录是否存在
dest.getParentFile().mkdir();
}
try {
file.transferTo(dest); //保存文件
return "true";
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return "false";
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return "false";
}
}
/*
* 获取multifile.html页面
*/
@RequestMapping("multifile")
public String multifile(){
return "/multifile";
}
/**
* 实现多文件上传
* */
@RequestMapping(value="multifileUpload",method=RequestMethod.POST)
/**public @ResponseBody String multifileUpload(@RequestParam("fileName")List<MultipartFile> files) */
public @ResponseBody String multifileUpload(HttpServletRequest request){
List<MultipartFile> files = ((MultipartHttpServletRequest)request).getFiles("fileName");
if(files.isEmpty()){
return "false";
}
String path = "F:/test" ;
for(MultipartFile file:files){
String fileName = file.getOriginalFilename();
int size = (int) file.getSize();
System.out.println(fileName + "-->" + size);
if(file.isEmpty()){
return "false";
}else{
File dest = new File(path + "/" + fileName);
if(!dest.getParentFile().exists()){ //判断文件父目录是否存在
dest.getParentFile().mkdir();
}
try {
file.transferTo(dest);
}catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return "false";
}
}
}
return "true";
}
}
5.遇见的问题
1>org.apache.tomcat.util.http.fileupload.FileUploadBase$FileSizeLimitExceededException:
The field fileName exceeds its maximum permitted size of 1048576 bytes.
SpringBoot的默认上传文件的大小是2m 如果你上传的文件超过了2m就会出现这样的错误。
这个时候我们可以再application.properties里面进行修改
multipart.maxFileSize=50Mb multipart.maxRequestSize=50Mb
或者新建一个类，加上@Configuration文件进行说明，这是一个配置类。
然后在类里面加上
@Bean
public MultipartConfigElement multipartConfigElement() {
MultipartConfigFactory factory = new MultipartConfigFactory();
//factory.setMaxFileSize(1024);
//单个文件最大
factory.setMaxFileSize("10240KB"); //KB,MB
/// 设置总上传数据总大小
factory.setMaxRequestSize("102400KB");
return factory.createMultipartConfig();
}
6.文件下载
@RequestMapping("/download")
public String downLoad(HttpServletResponse response) throws UnsupportedEncodingException {
String filename="2.xlsx";
String filePath = "D:/download" ;
File file = new File(filePath + "/" + filename);
if(file.exists()){ //判断文件父目录是否存在
response.setContentType("application/vnd.ms-excel;charset=UTF-8");
response.setCharacterEncoding("UTF-8");
// response.setContentType("application/force-download");
response.setHeader("Content-Disposition", "attachment;fileName=" + java.net.URLEncoder.encode(filename,"UTF-8"));
byte[] buffer = new byte[1024];
FileInputStream fis = null; //文件输入流
BufferedInputStream bis = null;
OutputStream os = null; //输出流
try {
os = response.getOutputStream();
fis = new FileInputStream(file);
bis = new BufferedInputStream(fis);
int i = bis.read(buffer);
while(i != -1){
os.write(buffer);
i = bis.read(buffer);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("----------file download---" + filename);
try {
bis.close();
fis.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return null;
}
本文来自：https://www.jianshu.com/p/be1af489551c