使用struts实现文件上传（基于httpservlet实现文件上传）

后台代码如下：

package com.isis.circuitaccept.web.opex.tools;

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.log4j.Logger;

/**
 * 
 * @ClassName: UploadUtil
 * @Description: 文件上传 servlet类
 * @author: VODE CODC
 * @date: 2019-11-15 下午3:41:51
 */
public class UploadUtilServlet extends HttpServlet {
    /**
     * @Fields serialVersionUID : TODO(用一句话描述这个变量表示什么)
     */
    private static final long serialVersionUID = 1L;

    // 环境变量 是存放上传文件的目标路径 可以设置为一个固定的路径 或者读取本地的环境变量
    public final static String ISS_HOME = "ISS_HOME";

    private static final String CONTENT_TYPE = "text/html;charset=UTF-8";

    private static String folderpath = "";
    
    private static final String TIME_FORMAT_STR = "yyyyMMddHHmmssSSS";
    Properties prop = new Properties();

    static Logger logger = Logger.getLogger(UploadUtilServlet.class);

    // 场景初始化方法上传文件 存放图片
    public void init() throws ServletException {
        super.init();
        folderpath = getAttachmentUpLoadHome();
        try {
            newFolder();
            logger.info(" 文件夹路径为：" + folderpath);
        } catch (IOException e) {
            logger.error(e.getMessage() + "新建文件错误");
        }
    }

    // 限制文件的上传大小
    private int maxPostSize = 200 * 1024 * 1024;

    public UploadUtilServlet() {
        super();
    }

    public void destroy() {
        super.destroy();
    }

    protected void processRequest(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {

//        String path = folderpath;

        response.setContentType(CONTENT_TYPE);
        // PrintWriter out = response.getWriter();
        // 保存文件到服务器中
        DiskFileItemFactory factory = new DiskFileItemFactory();
        factory.setSizeThreshold(4096);
        ServletFileUpload upload = new ServletFileUpload(factory);
        upload.setSizeMax(maxPostSize);
        try {
            List fileItems = upload.parseRequest(request);
            Iterator iter = fileItems.iterator();
            while (iter.hasNext()) {
                FileItem item = (FileItem) iter.next();
                if (!item.isFormField()) {
                    String name = item.getName();
                    logger.info("文件名称是："+name );
                    try {
                        SimpleDateFormat f = new SimpleDateFormat(TIME_FORMAT_STR);

                        String[] str = name.split("\\.");
                        String filetype = str[str.length - 1];
                        logger.info("文件类型是：" + filetype);

                        name = f.format(new Date())
                                + new Integer(
                                        new java.util.Random(100).nextInt())
                                        .toString() + "." + filetype;

                        folderpath = folderpath + File.separator + name;

                        item.setFieldName(name);
                        logger.info("最终文件路径：" + folderpath );

                        item.write(new File(folderpath + ""));
                        response.getWriter().write("success:"+folderpath);
                    } catch (Exception e) {
                        logger.error(e.getMessage() + "文件上传出错");
                        e.printStackTrace();
                        response.getWriter().write("fail");
                    }
                }
            }
        } catch (FileUploadException e) {
            e.printStackTrace();
            logger.info(e.getMessage() + "结束");
        }
    }

    /**
     * 
     * @Title: newFolder
     * @Description:创建文件保存目录
     * @param: @param folderPath
     * @param: @return
     * @param: @throws IOException
     * @return: File
     */
    public static File newFolder() throws IOException {

        // 按天创建文件夹
        File myFilePath = new File(folderpath);
        if (!myFilePath.exists()) {
            myFilePath.mkdirs();
        }
        return myFilePath;
    }

    /**
     * 
     * @Title: getAttachmentUpLoadHome
     * @Description: 获取环境变量 创建文件存放路径 按天生成路径 ex:D:\\upload\\20191119
     * @param: @return
     * @return: String
     */
    public static String getAttachmentUpLoadHome() {
        String home_path = System.getenv(ISS_HOME);
        String path = "attachmentUpLoad";
        //如果没有读取到本地环境变量，文件会默认保存在tomcat目录中的
        if (home_path != null) {
            path = home_path;
            SimpleDateFormat ff = new SimpleDateFormat("yyyyMMdd");
            String dayFile = ff.format(new Date());
            path = path + File.separator + dayFile;
        }else {
            logger.error("Environment variable does not exist");
        }

        return path;
    }

    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        processRequest(request, response);
    }

    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");
        processRequest(request, response);
    }

    public String getServletInfo() {
        return "Short description";
    }

    public static void main(String[] args) {
        UploadUtilServlet uploadUtilServlet = new UploadUtilServlet();
        System.out.println(uploadUtilServlet.getAttachmentUpLoadHome());
    }

}

 

       文件的保存目录可以通过环境变量读取，也可以通过手动配置的方式定义。文件目录的创建是按照每天进行目录的创建，如下如：

前台代码：

(前台是简单的jsp，只是作为简单的示例)

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>文件上传的页面</title>
</head>
<body>

<!-- 请求方式必须是post  enctype的属性必须是multipart/form-data -->
<form action="${pageContext.request.contextPath }/UploadUtilServlet"
      method="post" enctype="multipart/form-data">
    <!-- 文件名：<input type="text" name="filename"/><br/> -->
    文件：<input type="file" name="file"/><br/> <input type="submit"
                                                    value="上传文件">
</form>
</body>
</html>

以上为全部代码，具体使用细节如下：

选择一个本地文件

 

 

 

 

点击提交，然后查看后台日志：

显示出了上传的文件名，文件类型，文件的保存路径。并向前台返回文件的保存路径。（这一步通常是ajax进行请求，然后拿到文件的保存路径或者是服务器文件的保存地址）