Question

spring mvc 怎么实现上传文件

Answer 1

springmvc文件上传
1.加入jar包：
commons-fileupload-1.2.2.jar
commons-io-2.0.1.jar
lperson.java中加属性，实现get ,set方法
private String photoPath;
2.创建WebRoot/upload目录，存放上传的文件

1 <sf:form id="p" action="saveOrUpdate"
2 method="post"
3 modelAttribute="person"
4 enctype="multipart/form-data">
5
6 <sf:hidden path="id"/>
7 name: <sf:input path="name"/><br>
8 age: <sf:input path="age"/><br>
9 photo: <input type="file" name="photo"/><br>

上面第9行文件上传框，不能和实体对象属性同名，类型不同

controller配置

1 12、文件上传功能实现 配置文件上传解析器
2 @RequestMapping(value={"/saveOrUpdate"},method=RequestMethod.POST)
3 public String saveOrUpdate(Person p,
4 @RequestParam("photo") MultipartFile file,
5 HttpServletRequest request
6 ) throws IOException{
7 if(!file.isEmpty()){
8 ServletContext sc = request.getSession().getServletContext();
9 String dir = sc.getRealPath(“/upload”); //设定文件保存的目录
10
11 String filename = file.getOriginalFilename(); //得到上传时的文件名
12 FileUtils.writeByteArrayToFile(new File(dir,filename), file.getBytes());
13
14 p.setPhotoPath(“/upload/”+filename); //设置图片所在路径
15
16 System.out.println("upload over. "+ filename);
17 }
18 ps.saveOrUpdate(p);
19 return "redirect:/person/list.action"; //重定向
20 }

3.文件上传功能实现 spring-mvc.xml 配置文件上传解析器

1 <!-- 文件上传解析器 id 必须为multipartResolver -->
2 <bean id="multipartResolver"
3 class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
4 <property name="maxUploadSize" value=“10485760"/>
5 </bean>
6
7 maxUploadSize以字节为单位：10485760 =10M id名称必须这样写

1 映射资源目录
2 <mvc:resources location="/upload/" mapping="/upload/**"/>

随即文件名常用的三种方式：
文件上传功能（增强：防止文件重名覆盖）
fileName = UUID.randomUUID().toString() + extName;
fileName = System.nanoTime() + extName;
fileName = System.currentTimeMillis() + extName;

1 if(!file.isEmpty()){
2 ServletContext sc = request.getSession().getServletContext();
3 String dir = sc.getRealPath("/upload");
4 String filename = file.getOriginalFilename();
5
6
7 long _lTime = System.nanoTime();
8 String _ext = filename.substring(filename.lastIndexOf("."));
9 filename = _lTime + _ext;
10
11 FileUtils.writeByteArrayToFile(new File(dir,filename), file.getBytes());
12
13 p.setPhotoPath("/upload/"+filename);
14
15 System.out.println("upload over. "+ filename);
16 }

图片显示 personList.jsp
1 <td><img src="${pageContext.request.contextPath}${p.photoPath}">${p.photoPath}</td>