Spring Web MVC 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("/");
    }
}   

 

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

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();
}