文件上传下载
准备工作
Spring Web MVC也是使用Apache的common-fileupload，因此要在lib里面添加如下的jar包：
commons-fileupload-1.2.2.jar、commons-io-2.4.jar
为了处理中文文件名称的上传下载，把前面HelloWorld讲过的filter配置上
在Spring的配置文件中，配置处理文件上传的bean，如下：
<bean id= "multipartResolver" class= "org.springframework.web.multipart.commons.CommonsMultipartResolver ">
<property name= "maxUploadSize" value= "104857600"/>
</bean>
配置上就好了，Spring会自动找的
文件上传
文件上传示例，先看Controller部分，这里只是一个最基本的演示：
@Controller
@RequestMapping(value = "/fileope")
public class FileUploadController {
@RequestMapping(value = "upload", method = RequestMethod.POST)
public String upload(
HttpServletRequest request, @RequestParam(value = "myFile", required = false) MultipartFile[] files) {
try {
for(int i=0;i<files.length;i++){
FileUploadUtils.upload(request, files[i]);
}
} catch (Exception e) {
e.printStackTrace();
}
return "success";
}
}
对应使用的FileUploadUtils：
public class FileUploadUtils {
//默认大小 50M
public static final long DEFAULT_MAX_SIZE = 52428800;
//默认上传的地址
public static String defaultBaseDir = "upload";
public static final String upload(HttpServletRequest request, MultipartFile file)throws Exception{
String filename = extractFilename(file, defaultBaseDir);
File desc = getAbsoluteFile(extractUploadDir(request), filename);
file.transferTo(desc);
return filename;
}
private static final File getAbsoluteFile(String uploadDir, String filename) throws IOException {
if(uploadDir.endsWith("/")) {
uploadDir = uploadDir.substring(0, uploadDir.length() - 1); }
if(filename.startsWith("/")) {
filename = filename.substring(0, uploadDir.length() - 1); }
File desc = new File(uploadDir + "/" + filename);
if(!desc.getParentFile().exists()) {
desc.getParentFile().mkdirs(); }
if(!desc.exists()) {
desc.createNewFile(); }
return desc;
}
public static final String extractFilename(MultipartFile file, String baseDir) throws UnsupportedEncodingException {
String filename = file.getOriginalFilename();
int slashIndex = filename.indexOf("/");
if (slashIndex >= 0) {
filename = filename.substring(slashIndex + 1);
}
filename = baseDir + "/" + filename;
return filename;
}
public static final String extractUploadDir(HttpServletRequest request) {
return request.getServletContext().getRealPath("/");
}
}
n上传的示例页面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<form action="/mvcexample/fileope/upload" method="post" enctype="multipart/form-data">
file1:<input type="file" name="myFile"/>
<br>
file2:<input type="file" name="myFile"/>
<br>
<input type="submit" value="上传">
</form>
文件下载
n下载的示例Controller的方法
@RequestMapping(value = "download", method = RequestMethod.GET)
public static void download(HttpServletRequest request,
HttpServletResponse response, String fileName) throws Exception {
response.setContentType("text/html;charset=UTF-8");
request.setCharacterEncoding("UTF-8");
BufferedInputStream bis = null;
BufferedOutputStream bos = null;
String newFileName = new String(fileName.getBytes("ISO8859-1"),"UTF-8");
String ctxPath = request.getSession().getServletContext()
.getRealPath("/") + FileUploadUtils.defaultBaseDir;
String downLoadPath = ctxPath +"/"+ newFileName;
long fileLength = new File(downLoadPath).length();
response.setHeader("Content-disposition", "attachment; filename="
+ new String(newFileName.getBytes("gb2312"), "ISO8859-1"));
response.setHeader("Content-Length", String.valueOf(fileLength));
bis = new BufferedInputStream(new FileInputStream(downLoadPath));
bos = new BufferedOutputStream(response.getOutputStream());
byte[] buff = new byte[2048];
int bytesRead;
while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
bos.write(buff, 0, bytesRead);
}
bis.close(); bos.close();
}