文件上传和下载
作者：互联网
1：导入包：
1 <dependencies> 2 <!--文件上传--> 3 <dependency> 4 <groupId>commons-fileupload</groupId> 5 <artifactId>commons-fileupload</artifactId> 6 <version>1.3.3</version> 7 </dependency> 8 <!--servlet-api导入高版本的--> 9 <dependency> 10 <groupId>javax.servlet</groupId> 11 <artifactId>javax.servlet-api</artifactId> 12 <version>4.0.1</version> 13 </dependency> 14 </dependencies>
2：配置：
1 <!--文件上传配置--> 2 <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> 3 <!-- 请求的编码格式，必须和jSP的pageEncoding属性一致，以便正确读取表单的内容，默认为ISO-8859-1 --> 4 <property name="defaultEncoding" value="utf-8"/> 5 <!-- 上传文件大小上限，单位为字节（10485760=10M） --> 6 <property name="maxUploadSize" value="10485760"/> 7 <property name="maxInMemorySize" value="40960"/> 8 </bean>
3：实现代码：
1 @RestController
2 public class FileController {
3
4 //@RequestParam("file") 将name=file控件得到的文件封装成CommonsMultipartFile 对象
5 //批量上传CommonsMultipartFile则为数组即可
6 @RequestMapping("/upload")
7 public String fileUpload(@RequestParam("file") CommonsMultipartFile file , HttpServletRequest request) throws IOException {
8
9 //获取文件名 : file.getOriginalFilename();
10 String uploadFileName = file.getOriginalFilename();
11
12 //如果文件名为空，直接回到首页！
13 if ("".equals(uploadFileName)){
14 return "redirect:/index.jsp";
15 }
16 System.out.println("上传文件名 : "+uploadFileName);
17
18 //上传路径保存设置
19 String path = request.getServletContext().getRealPath("/upload");
20 //如果路径不存在，创建一个
21 File realPath = new File(path);
22 if (!realPath.exists()){
23 realPath.mkdir();
24 }
25 System.out.println("上传文件保存地址："+realPath);
26
27 InputStream is = file.getInputStream(); //文件输入流
28 OutputStream os = new FileOutputStream(new File(realPath,uploadFileName)); //文件输出流
29
30 //读取写出
31 int len=0;
32 byte[] buffer = new byte[1024];
33 while ((len=is.read(buffer))!=-1){
34 os.write(buffer,0,len);
35 os.flush();
36 }
37 os.close();
38 is.close();
39 return "redirect:/index.jsp";
40 }
41
42 /*
43 * 采用file.Transto 来保存上传的文件
44 */
45 @RequestMapping("/upload2")
46 public String fileUpload2(@RequestParam("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {
47
48 //上传路径保存设置
49 String path = request.getServletContext().getRealPath("/upload");
50 File realPath = new File(path);
51 if (!realPath.exists()){
52 realPath.mkdir();
53 }
54 //上传文件地址
55 System.out.println("上传文件保存地址："+realPath);
56
57 //通过CommonsMultipartFile的方法直接写文件（注意这个时候）
58 file.transferTo(new File(realPath +"/"+ file.getOriginalFilename()));
59
60 return "redirect:/index.jsp";
61 }
62
63 @RequestMapping(value="/download")
64 public String downloads(HttpServletResponse response , HttpServletRequest request) throws Exception{
65 //要下载的图片地址
66 String path = request.getServletContext().getRealPath("/upload");
67 String fileName = "logo.png";
68
69 //1、设置response 响应头
70 response.reset(); //设置页面不缓存,清空buffer
71 response.setCharacterEncoding("UTF-8"); //字符编码
72 response.setContentType("multipart/form-data"); //二进制传输数据
73 //设置响应头
74 response.setHeader("Content-Disposition",
75 "attachment;fileName="+ URLEncoder.encode(fileName, "UTF-8"));
76
77 File file = new File(path,fileName);
78 //2、 读取文件--输入流
79 InputStream input=new FileInputStream(file);
80 //3、 写出文件--输出流
81 OutputStream out = response.getOutputStream();
82
83 byte[] buff =new byte[1024];
84 int index=0;
85 //4、执行 写出操作
86 while((index= input.read(buff))!= -1){
87 out.write(buff, 0, index);
88 out.flush();
89 }
90 out.close();
91 input.close();
92 return null;
93 }
94
95
96 }
标签：文件,String,realPath,File,file,new,上传,下载 来源： https://www.cnblogs.com/nuyan/p/15490246.html