Spring MVC 的檔案上傳和下載
阿新 • • 發佈:2018-12-19
“君看一葉舟,出沒風波里” 使用Spring MVC 進行檔案的上傳和下載,除了Spring MVC 的jar包之外,還需用到commons-fileupload-1.2.2.jar、commons-io-2.1.jar兩個包。這裡已給出下載地址:jar包下載地址
- 檔案上傳的jsp頁面:
PS:這裡要注意,在form標籤中,有個屬性:
enctype="multipart/form-data"
,要使用上傳功能,則必須加此屬性。
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <%@taglib prefix="form" uri="http://www.springframework.org/tags/form" %> <html> <head> <title>使用者註冊</title> </head> <body> <h3>使用者註冊</h3> <form method="post" action="register" enctype="multipart/form-data"> <table> <tr> <td><label>使用者名稱:</label></td> <td><input type="text" name="username"></td> </tr> <tr> <td><label>請上傳頭像:</label></td> <td><input type="file" name="image"></td> </tr> <tr> <td><input type="submit" value="註冊"/></td> </tr> </table> </form> </body> </html>
- Spring MVC的配置:
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> <!--上傳檔案大小上限,單位為位元組--> <property name="maxUploadSizePerFile"> <value>10485760</value> </property> <!--請求的編碼格式,必須和jsp的pageEncoding屬性一致,以便正確讀取表單的內容,預設為ISO-8859-1--> <property name="defaultEncoding"> <value>UTF-8</value> </property> </bean>
- User實體類:
import org.springframework.web.multipart.MultipartFile; import java.io.Serializable; /** * @author aRunner * @date 2018/10/27 */ public class User implements Serializable { private String username; private MultipartFile image; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public MultipartFile getImage() { return image; } public void setImage(MultipartFile image) { this.image = image; } }
- 處理上傳檔案的Controller程式碼:
//上傳檔案會自動繫結到MultipartFile中
@RequestMapping(value = "/register")
public String register(HttpServletRequest request, @ModelAttribute User user,Model model) throws Exception{
System.out.println(user.getUsername());
//如果檔案不為空,寫入檔案路徑
if (!user.getImage().isEmpty()) {
//檔案上傳路徑
String path = request.getServletContext().getRealPath("/images/");
//上傳檔名
String filename = user.getImage().getOriginalFilename();
File filepath = new File(path, filename);
//判斷路徑是否存在,如果不存在就建立一個
if (!filepath.isDirectory()) {
filepath.getParentFile().mkdir();
}
//將上傳檔案儲存到一個目標檔案當中
user.getImage().transferTo(new File(path + File.separator + filename));
//將使用者新增到model
model.addAttribute("user",user);
//跳轉到下載頁面
return "userInfo";
}else {
return "error";
}
}
- 上傳成功之後跳轉到提供下載的頁面:
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<html>
<head>
<title>測試下載檔案</title>
</head>
<body>
<h3>檔案下載</h3>
<a href="download?filename=${requestScope.user.image.originalFilename}">
${requestScope.user.image.originalFilename}
</a>
</body>
</html>
- 處理下載請求的Controller程式碼:
//上傳檔案會自動繫結到MultipartFile中
@RequestMapping(value = "/download")
public ResponseEntity<byte[]> download(HttpServletRequest request,
@RequestParam("filename") String filename, Model model) throws Exception{
//下載檔案路徑
String path = request.getServletContext().getRealPath("/images/");
File file = new File(path + File.separator + filename);
HttpHeaders headers = new HttpHeaders();
//下載顯示的檔名,解決中文名稱亂碼問題
String downloadFileName = new String(filename.getBytes("UTF-8"), "ISO-8859-1");
//通知瀏覽器以attachment(下載方式)開啟圖片
headers.setContentDispositionFormData("attachment",downloadFileName);
//application/octet-stream:二進位制流資料(最常見的檔案下載)
headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
//201HttpStatus.CREATED
return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),headers,HttpStatus.CREATED);
}