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SpringMVC实现文件上传和下载功能 SpringMVC实现文件上传和下载功能

AltErNatiVe 人气:0

文件上传 

第一步,加入jar包:

commons-fileupload-1.3.1.jar
commons-io-2.4.jar

第二步,在SpringMVC配置文件中配置CommonsMultipartResovler

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
 <property name="defaultEncoding" value="utf-8"></property>
  //最大上传文件大小
 <property name="maxUploadSize" value="1048576"></property>
</bean> 

第三步,前端表单   注意 【POST请求,file类型,enctype="multipart/form-data"】

<form action="${pageContext.request.contextPath }/testUpload" method="post" enctype="multipart/form-data">
 File:<input type="file" name="file"><br>
 desc:<input type="text" name="desc"><br>
 <input type="submit" value="submit"><br>
</form><br>

第四步,在controller层创建方法

@RequestMapping(value="/testUpload",method=RequestMethod.POST)
    private String testUpload(HttpServletRequest request,@RequestParam(value="desc")String desc,@RequestParam(value="file") CommonsMultipartFile file) {

    InputStream inputStream = null;
    OutputStream outputStream = null;
    ServletContext servletContext = request.getServletContext();
    //获取文件存放的真实路径
    String realPath = servletContext.getRealPath("/upload");
    //为了避免多次上传同一个文件导致命名重复,在文件名前加UUID前缀
    String prefix=UUID.randomUUID().toString();
    prefix=prefix.replace("-", "");
    String fileName=prefix+"_"+file.getOriginalFilename();
 
    File file2=new File(realPath);
    //检查文件目录是否存在,若不存在就创建目录
    if(!file2.exists()){
    file2.mkdirs();
    }
 
    try {
    inputStream=file.getInputStream();
    outputStream=new FileOutputStream(new File(realPath+"/"+fileName));
    //设置缓冲区
    byte[]buffer=new byte[1024];
    int len=0;
    //循环检测文件是否上传完成,未完成就向写入输出流
    while((len=inputStream.read(buffer)) != -1){
    outputStream.write(buffer, 0, len);
    outputStream.flush();
    }
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    } finally{
    //关闭输入输出流
    if(outputStream !=null){
    try {
    outputStream.close();
    inputStream.close();
    } catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
    }
    }
   }
 
 return "success";
 }

 文件下载 

用ResponseEntity<byte[]> 返回值完成文件下载;在jsp页面给出链接即可。

jsp页面链接地址:

复制代码 代码如下:
<a href="${pageContext.request.contextPath }/testResponseEntity" rel="external nofollow" >下载链接</a> 

在controller层创建方法

@RequestMapping(value="/testResponseEntity")
 ResponseEntity<byte[]>testResponseEntity(HttpServletRequest request)throws Exception{
 ServletContext servletContext = request.getServletContext();
 //获取要下载的文件的文件名
 String fileName="喜剧之王.mp3";
 //获取要下载的文件的真实路径
 String realPath = servletContext.getRealPath("/WEB-INF/"+fileName);
 //创建输入流
 InputStream inputStream=new FileInputStream(new File(realPath));
 
 byte[]body=new byte[inputStream.available()];
 inputStream.read(body);
 MultiValueMap<String, String>headers=new HttpHeaders();
 
 //设置头信息和字符集
 fileName = new String(fileName.getBytes("gbk"),"iso8859-1");
 headers.set("Content-Disposition", "attachment;filename="+fileName);
 
 HttpStatus statusCode = HttpStatus.OK;
 ResponseEntity<byte[]>responseEntity =new ResponseEntity<byte[]>(body, headers, statusCode);
 
 return responseEntity;
 }

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