相信有过web开发经历的小朋友，对于文件上传都不陌生，但如何在自己的网站上提供文件上传呢？我想一定难到过很多同学，我就是其中的一个，近段时间因为开发的需要，总结了一下web端文件上传的原理，在这里和大家分享一下。
jsp页面的主要代码：
<body> <h1>单文件上传</h1> <hr/> <form action="upload" method="post" enctype="multipart/form-data"> 文件<input type="file" name="img1"/><br/> <input type="submit" value="上传"/> </form> <h1>文件重命名</h1> <hr/> <form action="upload2" method="post" enctype="multipart/form-data"> 文件名<input type="text" name="imgname"/><br/> 文件<input type="file" name="img1"/><br/> <input type="submit" value="上传"/> </form> <h1>自动生成文件名</h1> <hr/> <form action="upload3" method="post" enctype="multipart/form-data"> 文件<input type="file" name="img1"/><br/> <input type="submit" value="上传"/> </form> <h1>多文件上传</h1> <hr/> <form action="upload4" method="post" enctype="multipart/form-data"> 文件1<input type="file" name="img1"/><br/> 文件2<input type="file" name="img1"/><br/> 文件3<input type="file" name="img1"/><br/> <input type="submit" value="上传"/> </form> </body>
下面是具体的上传方法介绍
<strong>单文件上传：</strong>
SmartUpload smart = new SmartUpload(); smart.initialize(this.getServletConfig(),request,response); try { smart.upload(); smart.save("images"); } catch (SmartUploadException e) { // TODO Auto-generated catch block e.printStackTrace(); }文件重命名：
SmartUpload smart = new SmartUpload(); smart.initialize(this.getServletConfig(),request,response); try { smart.upload(); String imgname = smart.getRequest().getParameter("imgname"); String absPath = this.getServletContext().getRealPath("/images");//获取文件的保存路径 System.out.println(absPath); String ext = smart.getFiles().getFile(0).getFileExt();//获取文件的后缀名 String fileName = absPath+File.separator+imgname+"."+ext;//生成文件的保存名 System.out.println("File name="+fileName); smart.getFiles().getFile(0).saveAs(fileName); } catch (SmartUploadException e) { // TODO Auto-generated catch block e.printStackTrace(); }<strong>自动生成文件名：</strong>
SmartUpload smart = new SmartUpload(); smart.initialize(this.getServletConfig(),request,response); String disFile = ""; try { smart.upload(); //String imgname = smart.getRequest().getParameter("imgname"); IPTimeStamp ipts = new IPTimeStamp(); String imgname = ipts.getIPTimestamp(); String absPath = this.getServletContext().getRealPath("/images"); System.out.println(absPath); String ext = smart.getFiles().getFile(0).getFileExt(); String fileName = absPath+File.separator+imgname+"."+ext; System.out.println("File name="+fileName); smart.getFiles().getFile(0).saveAs(fileName); disFile = imgname+"."+ext; } catch (SmartUploadException e) { // TODO Auto-generated catch block e.printStackTrace(); }生成随机文件名的代码：
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package cn.edu.hpu.util;import java.text.SimpleDateFormat;import java.util.Date;import java.util.Random;public class IPTimeStamp { private String ip; public IPTimeStamp() { } public IPTimeStamp(String ip) { this.ip = ip; } public String getIPTimestamp() { StringBuffer buffer = new StringBuffer(); if(ip != null) { String [] digits = ip.split("\."); for(String s : digits) { buffer.append(s); } } //时间 SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmssSSS"); String time = sdf.format(new Date()); buffer.append(time); Random random = new Random(); for(int i=0; i<4; i++) { buffer.append(random.nextInt(10)); } return buffer.toString(); } public static void main(String[] args) { IPTimeStamp ipts = new IPTimeStamp("192.168.19.121"); System.out.println(ipts.getIPTimestamp()); }}<strong>多文件上传：</strong>
SmartUpload smart = new SmartUpload(); smart.initialize(this.getServletConfig(),request,response); try { smart.upload(); for(int i=0; i<smart.getFiles().getCount(); i++) { //String imgname = smart.getRequest().getParameter("imgname"); IPTimeStamp ipts = new IPTimeStamp(); String imgname = ipts.getIPTimestamp(); String absPath = this.getServletContext().getRealPath("/images");//文件保存的路径 String ext = smart.getFiles().getFile(i).getFileExt();//获得文件的后缀名 String fileName = absPath+File.separator+imgname+"."+ext;//生成上传文件的保存时的名字 System.out.println("File name="+fileName); smart.getFiles().getFile(i).saveAs(fileName); } } catch (SmartUploadException e) { // TODO Auto-generated catch block e.printStackTrace(); }相信看到这里，大家一定已经明白如何完成文件上传了。(如有错误还望指正。谢谢)
