<SpringMvc>入门五 文件上传

文件上传的必要条件：

　　1.form表单的enctype取值必须是：mutipart/form-data (默认是:application/x-www-form-urlencoded)

　　2.method属性为：post

　　3.提供一个文本选择域<input type="file" />

        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.3</version>
        </dependency>
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.6</version>
        </dependency>

1.传统的方式上传

form表单

    <form action="/fileupload/f1" method="post" enctype="multipart/form-data" >
        选择文件:<input type="file" name="upload">
                <input type="submit" value="上传">
    </form>

controller类，生成的文件在target根目录下的uploads文件夹中

@Controller
@RequestMapping("/fileupload")
public class FileuploadController {

    /**
     * 传统的文件上传方式
     */
    @RequestMapping("/f1")
    public String f1(HttpServletRequest request) throws Exception {
        //用fileupload组件完成文件上传
        String path = request.getSession().getServletContext().getRealPath("/uploads");
        //判断该路径是否存在
        File file = new File(path);
        if(!file.exists()){
            //创建该文件夹
            file.mkdirs();
        }

        //解析request对象，获取文件上传项
        DiskFileItemFactory factory = new DiskFileItemFactory();
        ServletFileUpload upload = new ServletFileUpload(factory);
        //解析request
        List<FileItem> items = upload.parseRequest(request);
        for (FileItem item : items) {
            //判断当前item对象是否是文件上传项
            if(item.isFormField()){
                //说明普通表单项
            }else {
                //说明文件上传项
                String fileName = item.getName();
                //把文件名称设置为唯一值 uuid
                String uuid = UUID.randomUUID().toString().replace("-", "");
                fileName = uuid +"_"+fileName;
                //完成文件上传
                item.write(new File(path,fileName));
                //删除临时文件
                item.delete();
            }
        }
        return "success";
    }
}

2.springmvc文件上传

 

1.配置文件解析器

    <!-- 配置文件解析器对象，要求id名称必须是multipartResolver -->
    <bean id="multipartResolver"
          class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!--字节单位-->
        <property name="maxUploadSize" value="10485760"/>
    </bean>

2.页面表单

    <%--springmvc模式--%>
    <form action="/fileupload/f2" method="post" enctype="multipart/form-data" >
        选择文件:<input type="file" name="upload">
        <input type="submit" value="上传">
    </form>

3.controller

    /**
     * springmvc模式的上传
     */
    @RequestMapping("/f2")
    public String f2(HttpServletRequest request, MultipartFile upload) throws IOException {
        String path = request.getSession().getServletContext().getRealPath("/uploads");
        File file = new File(path);
        if(!file.exists()){
            file.mkdirs();
        }
        //获取文件名字
        String filename = upload.getOriginalFilename();
        String uuid = UUID.randomUUID().toString().replace("-", "");
        filename = uuid +"_"+filename;
        //完成上传
        upload.transferTo(new File(path,filename));
        return "success";
    }