ssm 上传和下载

1 导入jar

        <dependencies>
        <dependency>
            <groupId>commons-fileuploadgroupId>
            <artifactId>commons-fileuploadartifactId>
            <version>1.3.1version>
        dependency>
        <dependency>
            <groupId>commons-iogroupId>
            <artifactId>commons-ioartifactId>
            <version>2.2version>
        dependency>

2 配置springmvc

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" p:prefix="/WEB-INF/page/" p:suffix=".jsp" />
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">    
    
    <property name="defaultEncoding" value="UTF-8">property>  
    
    <property name="maxUploadSize" value="10485760">property>    
    bean> 

3 上传代码

@RequestMapping("upload")
    public String upload(MultipartFile file,HttpServletRequest request)
    {
        String fileName = file.getOriginalFilename();    
        File dir = new File("e:/temp/",fileName);          
        if(!dir.exists()){  
            dir.mkdirs();  
        }  
        //MultipartFile自带的解析方法  
        try {
            file.transferTo(dir);
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
//        DispatcherServlet 
        return "index";
    }

    @RequestMapping("hello")
    public String index(String page)
    {
        return "index";
    }

4 下载代码

    @RequestMapping("down")  
    public void down(HttpServletRequest request,HttpServletResponse response) throws Exception{  
        //模拟文件，myfile.txt为需要下载的文件  
        String fileName = request.getSession().getServletContext().getRealPath("upload")+"/myfile.txt";  
        //获取输入流  
        InputStream bis = new BufferedInputStream(new FileInputStream(new File(fileName)));  
        //假如以中文名下载的话  
        String filename = "下载文件.txt";  
        //转码，免得文件名中文乱码  
        filename = URLEncoder.encode(filename,"UTF-8");  
        //设置文件下载头  
        response.addHeader("Content-Disposition", "attachment;filename=" + filename);    
        //1.设置文件ContentType类型，这样设置，会自动判断下载文件类型    
        response.setContentType("multipart/form-data");   
        BufferedOutputStream out = new BufferedOutputStream(response.getOutputStream());  
        int len = 0;  
        while((len = bis.read()) != -1){  
            out.write(len);  
            out.flush();  
        }  
        out.close();  
    }  

5丶 jsp页面上传时注意给from加

method="post" enctype="multipart/form-data"

这两个关键

6丶 下载的时候需要注意有没有这个文件夹 和文件 没有的话就创建一个
并且把页面改成 method=“ get”