利用spring的MultipartFile实现文件上传

主要依赖jar包

spring-web-3.0.6.RELEASE.jar 用到 (org.springframework.web.multipart.MultipartFile)
commons-fileupload-1.3.1.jar
commons-logging-1.0.4.jar

前台

<!DOCTYPE html>

<html lang="en">

<head>

<meta charset="utf-8">

<title>上传</title>

<style type="text/css">

</style>

</head>

<body>

    <form enctype="multipart/form-data" action="/kingtool/file/upload.do" method="POST">

        file:

        <input id="file" type="file" name="file" />

        <input type="submit" value="提交" />

    </form>

</body>

</html>

后台

package com.bobo.code.web.controller;

import java.io.File;

import java.io.IOException;

import java.math.BigDecimal;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;

import org.springframework.ui.ModelMap;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.multipart.MultipartFile;

@Controller

@RequestMapping({ "file/*" })

public class LoginController {

    /**

     * 承保文件上传

     *

     * @param session

     */

    @RequestMapping(value = "upload.do", method = { RequestMethod.POST, RequestMethod.GET })

    public void fileUpload(HttpSession session, ModelMap modelMap, HttpServletResponse response, HttpServletRequest request, @RequestParam("file") MultipartFile file) throws Exception, IOException {

        String ret = "";

        request.setCharacterEncoding("UTF-8");// 编码格式处理

        // 获取文件名

        String fileName = file.getOriginalFilename();

        System.out.println("fileName:------------------------------------------------------" + fileName);

        // 获取文件大小kb

        BigDecimal fileSize = new BigDecimal(file.getSize()).divide(new BigDecimal(1024), 2, BigDecimal.ROUND_HALF_UP);

        String startFileName = fileName.substring(0, fileName.indexOf("."));

        String endFileName = fileName.substring(fileName.lastIndexOf("."));

        // 新文件名称

        String newFileName = startFileName + "_" + Math.random() + endFileName;

        // 文件保存路径

        String parentPath = request.getSession().getServletContext().getRealPath("/") + "upload/";

        String filePath = parentPath + newFileName;

        System.out.println("filePath:-----------------------------------------------------------" + filePath);

        System.out.println("System.setProperty('sun.jnu.encoding') --------" + System.getProperty("sun.jnu.encoding"));

        System.setProperty("sun.jnu.encoding", "utf-8");

        System.out.println("System.setProperty('sun.jnu.encoding') --------" + System.getProperty("sun.jnu.encoding"));

        File newFile = new File(parentPath);

        if (!newFile.exists()) {// 判断文件夹是否创建，没有创建则创建新文件夹

            newFile.mkdirs();

        }

        boolean uploadFile = true;

        // 比较上传文件大小是否超过10M

        if (fileSize.compareTo(new BigDecimal(1024 * 10)) > 0) {

            uploadFile = false;

            ret = "上传文件的大小不能超过10Mb,请重新选择!";

        }

        if (uploadFile) {

            try {

                file.transferTo(new File(filePath));// 转存文件

                ret = "上传成功!";

            } catch (Exception e) {

                ret = "上传失败!";

            }

        }

        try {

            response.setContentType("text/html;charset=UTF-8");

            response.getWriter().write(ret);

            response.getWriter().flush();

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

}

spring bean配置

    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

       <!-- maxUploadSize:文件上传的最大值以byte为单位 -->

       <property name="maxUploadSize" value="1024000"></property>

       <property name="defaultEncoding" value="GBK"></property>

    </bean>

如果不配置,可能报如下错org.springframework.web.bind.MissingServletRequestParameterException: Required MultipartFile parameter 'file' is not present

遇见异常

异常 Required request part 'file' is not present

我遇到的问题和网上的完全不一样, 在springboot中为了能对所有获取到的request提前打印请求报文,在filter又做了一层request wraper包装处理 , 导致file 参数丢失了.

@Component

@WebFilter(filterName = "httpServletRequestFilter", urlPatterns = {

        "/controller/**",

        "/j_spring_security_check**"})

@Order(-)

public class HttpServletRequestFilter implements Filter {

    private static final Logger logger = LoggerFactory.getLogger(HttpServletRequestFilter.class);

    @Override

    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

        BufferedServletRequestWrapper requestWrapper = null;

        if (servletRequest instanceof HttpServletRequest) {

            requestWrapper = new BufferedServletRequestWrapper((HttpServletRequest) servletRequest);

            HttpSession session = requestWrapper.getSession();

            try {

                logger.info("----------------------------------------------------------------------");

                logger.info("HttpServletRequestFilter");

                logger.info("url: " + requestWrapper.getRequestURL() + "?" + requestWrapper.getQueryString());

                logger.info("sessionId: " + session.getId());

                logger.info("servletPath: " + requestWrapper.getServletPath());

                logger.info("requestMethod: " + requestWrapper.getMethod());

                logger.info("requestHeader: " + HttpServletRequestFilter.getStringFromHead((HttpServletRequest) servletRequest));

                logger.info("body: " + HttpServletRequestFilter.getStringFromStream(requestWrapper));

                logger.info("----------------------------------------------------------------------\n\n");

            } catch (Exception e) {

                e.printStackTrace();

            }

            filterChain.doFilter(requestWrapper, servletResponse);

        } else {

            filterChain.doFilter(servletRequest, servletResponse);

        }

    }

}

ajax文件上传

如果用ajax文件上传时注意contentType:false 一定要为false, 不要自传多情传什么 contentType: "multipart/form-data;charset=utf-8;boundary=" + Math.random(),

不然springboot的后台controller死活不成功, 永远报错为: MissingServletRequestPartException: Required request part 'file' is not present

<script type="text/javascript">

    function upload() {

        $("#result").html("upload");

        var formData = new FormData();

        formData.append("file", $("#file")[0].files[0]);

        $.ajax({

            url: 'http://localhost/controller/finance/asset/manager/upload',

            type: 'post',

            data: formData,

            contentType: false,

            processData: false,

            success: function (res) {

                $("#result").html(res);

            }

        });

    }

</script>

本小节参考: 解决springboot MultipartFile文件上传遇到的问题==>http://www.manongjc.com/article/4682.html

参考

MultipartFile+ajax图片上传==>https://blog.csdn.net/q394503873/article/details/80737323