SpringMVC文件上传

1.在SpringMVC中的配置文件dispatcherServlet-servlet.xml中加入

    <!-- 配置MultipartResolver，用于上传文件，使用spring的CommonsMultipartResolver -->  
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
            <property name="maxUploadSize" value="5000000"/>
            <property name="defaultEncoding" value="UTF-8"/>
    </bean>


2.处理文件上传-单文件传-在controller类里添加
    //文件上传
    //添加用户时，为post请求，访问以下代码
    @RequestMapping(value="/adduser",method=RequestMethod.POST)
    public String add(@Validated User user,BindingResult bindingResult,MultipartFile attach,HttpServletRequest req){//紧跟validate之后写验证结果
        if(bindingResult.hasErrors()){
            System.out.println("@Validated User user-->"+user);
            //若有错误，直接掉转到add 视图
            return "user/add";
        }
        //判断文件是否为空
        if(!attach.isEmpty()){
            //指定文件上传位置
            String realPath =  req.getSession().getServletContext().getRealPath("/resources/upload");
            System.out.println("realPath===="+realPath);
            System.out.println("原始文件的名字"+attach.getOriginalFilename());
            System.out.println(attach.getContentType());
            System.out.println(attach.getName());//得到页面表单控件的值
            
            //建立空文件
            //File.separator="/",File.separator:路径自适应分隔符，适合其它操作系统， 
            File file = new File(realPath+File.separator+attach.getOriginalFilename());
            
            try {
                FileUtils.copyInputStreamToFile(attach.getInputStream(), file);
                //FileUtils.writeByteArrayToFile(file, attach.getBytes());
                //attach.transferTo(file);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println(attach.getName()+" ======= "+attach.getOriginalFilename()+" ====== "+attach.getContentType());
        }
        userList.put(user.getUserName(), user);
        return "redirect:/user/userlist";
    }
    
    




3.处理文件上传-多文件上传

    //添加用户时，为post请求，访问以下代码
    @RequestMapping(value="/adduser",method=RequestMethod.POST)
    public String add(@Validated User user,BindingResult bindingResult,@RequestParam("attachs") MultipartFile[] attachs,HttpServletRequest req){//紧跟validate之后写验证结果
        if(bindingResult.hasErrors()){
            //若有错误，直接掉转到add 视图
            return "user/add";
        }
        
        String realPath =  req.getSession().getServletContext().getRealPath("/resources/upload");
        System.out.println(realPath);
        //循环
        for(MultipartFile attach:attachs){
            if(!attach.isEmpty()){//判断文件是否为空
                File file = new File(realPath+"/"+attach.getOriginalFilename());
                try {
                    //FileUtils.copyInputStreamToFile(attach.getInputStream(), file);
                    //FileUtils.writeByteArrayToFile(file, attach.getBytes());
                    attach.transferTo(file);
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
        userList.put(user.getUserName(), user);
        return "redirect:/user/userlist";
    }





4.在add.jsp中的form表单中添加，如果是多文件上传就按照需求添加
    <!--单文件上传文件-->
    Attach:<input type="file" name="attach"/>

        <!--多文件上传文件，注意：attachs-->
            Attach1:<input type="file" name="attachs"/><br/>
        Attach2:<input type="file" name="attachs"/><br/>
        Attach3:<input type="file" name="attachs"/><br/>
        Attach4:<input type="file" name="attachs"/><br/>