Java文件上传处理-优快云博客

本文链接：https://blog.youkuaiyun.com/yeahrobin/article/details/83528348
package com.fuyou;

import java.io.File;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.Iterator;

import java.util.List;

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.FileItemFactory;

import org.apache.commons.fileupload.FileUploadException;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class Fileupload extends HttpServlet {

    /**

     * Constructor of the object.

     */

    public Fileupload() {

        super();

    }

    /**

     * Destruction of the servlet. <br>

     */

    public void destroy() {

        super.destroy(); // Just puts "destroy" string in log

        // Put your code here

    }

    /**

     * The doGet method of the servlet. <br>

     *

     * This method is called when a form has its tag value method equals to get.

     *

     * @param request

     *            the request send by the client to the server

     * @param response

     *            the response send by the server to the client

     * @throws ServletException

     *             if an error occurred

     * @throws IOException

     *             if an error occurred

     */

    public void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        response.setContentType("text/html");

        PrintWriter out = response.getWriter();

        out

                .println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");

        out.println("<HTML>");

        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");

        out.println("  <BODY>");

        out.print("    This is ");

        out.print(this.getClass());

        out.println(", using the GET method");

        out.println("  </BODY>");

        out.println("</HTML>");

        out.flush();

        out.close();

    }

    /**

     * The doPost method of the servlet. <br>

     *

     * This method is called when a form has its tag value method equals to

     * post.

     *

     * @param request

     *            the request send by the client to the server

     * @param response

     *            the response send by the server to the client

     * @throws ServletException

     *             if an error occurred

     * @throws IOException

     *             if an error occurred

     */

    public void doPost(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

    System.out.println("requestCo"+"=="+request.getContentType());

        response.setContentType("text/html;charset=gb2312");

        PrintWriter out = response.getWriter();

        // 设置保存的文件的目录

        String uploadDir = getServletContext().getRealPath("/upload");

        System.out.println(uploadDir);

        if (uploadDir == null) {

            out.println("无法访问存储目录!");

            return;

        }

        File fUploadDir = new File(uploadDir);

        if (!fUploadDir.exists()) {

            if(!fUploadDir.mkdir()){

            out.println("无法创建存储目录!");

            return;

            }

        }

        if (!ServletFileUpload.isMultipartContent(request)) {

            out.println("只能外理mul的类型的数据");

            return;

        }

     FileItemFactory factory = new DiskFileItemFactory();

        ServletFileUpload  fu = new ServletFileUpload(factory);//关键类

        fu.setSizeMax(1024 * 1024 * 400);

        // FileItemFactory factory = new DiskFileItemFactory();

        DiskFileItemFactory s = new DiskFileItemFactory();//设置临时文件最大值,如果大于这个值,就建一临时文件

        s.setSizeThreshold(1024*1024);

        fu.setHeaderEncoding("gb2312");

        List fileItem = null;

        try {

            fileItem = fu.parseRequest(request);

        } catch (FileUploadException e) {

            out.println("解析出错了");

            e.printStackTrace(out);

            return;

        }





        Iterator i = fileItem.iterator();

        while (i.hasNext()) {

            FileItem fi = (FileItem) i.next();

            if (fi.isFormField()) {

                String content = fi.getString("gb2312");

                String fieldName = fi.getFieldName();

                System.out.println(fieldName+content);

            } else {

                String pathSrc = fi.getName();

                if (pathSrc.trim().equals("")) {

                    continue;

                }

                int start = pathSrc.lastIndexOf("\\");

                String fileName = pathSrc.substring(start + 1);

                File pathDest = new File(uploadDir, fileName);

                try {

                    fi.write(pathDest);

                    String fieldName = fi.getFieldName();

                    request.setAttribute(fileName, fileName);

                } catch (Exception e) {

                    out.println("存储文件出现问题");

                    e.printStackTrace(out);

                    return;

                }finally{

                    fi.delete();

                }

            }

        }

    }

    /**

     * Initialization of the servlet. <br>

     *

     * @throws ServletException

     *             if an error occurs

     */

    public void init() throws ServletException {

        // Put your code here

    }

}



迟点再来示例一个使用dwr来显示上传进度的。
大文件上传
