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
单文件上传：
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 blocke.printStackTrace();}自动生成文件名：
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 blocke.printStackTrace();}生成随机文件名的代码：
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());}}
多文件上传：
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 blocke.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)
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