先附上图片上传的代码

jsp代码如下：

<form action="${path}/upload/uploadPic.do" method="post" enctype="multipart/form-data">      
<div>
       ![](${path}/mall/image/load_image.png)
       <input type="file" id="input-image" name="input-image">
       <input id="input-relative-path" name="imgs" type="hidden" >
       <input id="input-last-path" type="hidden">
       <input type="submit" value="上传图片">
 </div>
</form>

controller代码：通过spring的方式实现

@Controller
@RequestMapping("/upload")
public class UploadController extends BaseController {
    @RequestMapping(value = "/uploadPic", method = RequestMethod.POST)
    @LoginCheck
    public void uploadPic(HttpServletRequest request, PrintWriter out, String lastRealPath) throws IOException {
        // 将当前上下文初始化给CommonsMultipartResolver
        CommonsMultipartResolver resolver = new CommonsMultipartResolver(request.getSession().getServletContext());
        // 检查form中是否有enctype＝"multipart／form－data"
        if (resolver.isMultipart(request)) {
            // 强制转化request
            MultipartHttpServletRequest req = (MultipartHttpServletRequest) request;
            // 从表单获取input名称
            Iterator<String> iterable = req.getFileNames();
            // 存在文件
            if (iterable.hasNext()) {
                String inputName = iterable.next();
                // 获得文件
                MultipartFile mf = req.getFile(inputName);
                byte[] mfs = mf.getBytes();
                // 定义文件名
                String fileName = new SimpleDateFormat("yyyyMMddHHmmssSSS").format(new Date());
                Random random = new Random();
                for (int i = 0; i < 3; i++) {
                    fileName = fileName + random.nextInt(10);
                }
                // 获得后缀名
               String oriFileName = mf.getOriginalFilename();
               String suffix = oriFileName.substring(oriFileName.lastIndexOf("."));
              
               // 上传图片到本地
               String localPath = "/Users/ZR/Desktop/webPro/console/src/main/webapp/image/" + fileName + suffix;
               mf.transferTo(new File(localPath));

               // 获取图片的宽高
               BufferedImage bufferedImage = ImageIO.read(new FileInputStream(new File(localPath)));
               int width = bufferedImage.getWidth();
               int height = bufferedImage.getHeight();
               // 获取文件大小
               long size = mf.getSize();
            }
        }
    }
}

spring-mvc.xml代码：

 <!--
    文件上传的视图解析器，id值是固定的
 -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <property name="maxUploadSize" value="1024000"/>
    <!-- 其他属性 -->
</bean>

功能的实现其实很简单，但是对于初学者还是需要注意如下几个点

• form上的enctype="multipart/form-data"不能忘记。
• <input type="file" onchange="submitUpload()" id="input-image" name="input-image"> 的name标签可以随便取名，但是不能忽略，否则Iterator<String> iterable = req.getFileNames();这边获取的集合将为空。

不注重细节只会让自己花更多的时间去debug