简单操作实现Java jsp servlet文件上传过程解析
实现文件上传的方式
1、进入http://commons.apache.org/proper/commons-fileupload/using.html
2、点击用户指南
3、对着用户指南一步步复制粘贴,并把代码撸成自己想要的样子
补充:记得要将commons-io-2.4.jar和commons-fileupload-1.2.2.jar这两个包放到编译器里面
现成的代码
JSP 前端页面
<%-- Created by IntelliJ IDEA. User: Administrator Date: 2019/10/8 Time: 16:14 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>作业三第1遍</title> </head> <body> 文件上传注意事项:<br> <ol> <li>提交方式必须是post</li> <li>enctype="multipart/form-data"是以字节数据的形式提交表单,否则默认是kv形式,只会提交文件名</li> <li>如果以默认的application/x-www-form-urlencode的方式提交,上传的就不是文件本身</li> </ol> <%--application/x-www-form-urlencoded 以键值对的方式上传 --%> <%-- multipart/form-data 以二进制的方式上传 --%> <form action="/work/UploadServlet" method="post" enctype="multipart/form-data"> <input type="text" name="data1" value="data1Value"> <hr> <input type="text" name="data2" value="data2Value"> <hr> <input type="file" name="dataFile"> <hr> <input type="submit" value="上传该表单"> <hr> </form> </body> </html>
Servlet 后台处理页面
package com.bd25; 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; import javax.servlet.ServletException; import javax.servlet.ServletInputStream; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.File; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.util.Enumeration; import java.util.Iterator; import java.util.List; @WebServlet(name = "UploadServlet", urlPatterns = "/UploadServlet") public class UploadServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //处理中文乱码--已经测试这个要不要无所谓 request.setCharacterEncoding("UTF-8"); //判断是不是传入的一个二进制的流 boolean isMultipart = ServletFileUpload.isMultipartContent(request); //创建一个简单工厂实例 FileItemFactory factory = new DiskFileItemFactory(); //创建一个新的文件上传处理程序 ServletFileUpload upload = new ServletFileUpload(factory); //解析request try { List<FileItem> fileItems = upload.parseRequest(request); //处理上传的项目 Iterator iter=fileItems.iterator(); while(iter.hasNext()){ FileItem item = (FileItem) iter.next(); if (item.isFormField()){ //普通域 processFormField(item); }else{ //文件域 此处注意processUploadFile()方法的参数里面传入request的目的是让下面写文件的时候获取根目录用的 processUploadFile(item,request); } } } catch (FileUploadException e) { e.printStackTrace(); } ServletInputStream inputStream = request.getInputStream(); byte[] bs=new byte[1024]; int total=-1; while ((total=inputStream.read(bs))!=-1){ System.out.print(new String(bs,0,total)); } } /** * 文件域 * @param item * @param request */ private void processUploadFile(FileItem item, HttpServletRequest request) { //获取文件相关信息 String fileName=""; if (!item.isFormField()) { String fieldName = item.getFieldName(); fileName = item.getName(); String contentType = item.getContentType(); boolean isInMemory = item.isInMemory(); long sizeInBytes = item.getSize(); System.out.println("文件名: "+fileName+" 文件属性:"+fieldName+" 文件大小:"+sizeInBytes+" 文件类型:"+contentType); } //以下是转存操作,找到储存文件的根路径 String fileRootPath=request.getServletContext().getRealPath("/WEB-INF/upload"); File dir = new File(fileRootPath); if (!dir.exists()){ dir.mkdirs(); } //写文件 File file = new File(fileRootPath+"/"+fileName); try { item.write(file); } catch (Exception e) { e.printStackTrace(); } } /** * 普通域 * @param item */ private void processFormField(FileItem item) { String key = item.getFieldName(); String value = null; try { //处理中文乱码 value = item.getString("UTF-8"); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } System.out.println(key+"----"+value); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } @Override protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { super.service(req, resp); System.out.println("刷新...."); } @Override public void init() throws ServletException { super.init(); System.out.println("初始化...."); } }
运行结果
//说明:路径出现的位置就是网页发布的路径
//说明:路径出现的位置就是网页发布的路径
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