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 block
e.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 block
e.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 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)