本文实例讲述了JSP实现快速上传文件的方法。分享给大家供大家参考。具体如下：
这里演示JSP不使用第三方库，实现快速上传文件的功能
1. FileUpload.java：
package FileUpload;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import javax.servlet.ServletInputStream;
/**
*
*/
/**
* @author Qch
*
*/
public class FileUpload
{
ServletInputStream in=null;
String fpath="C://";
public FileUpload()
{
fpath="C://";
in=null;
}
public void setInputStream(ServletInputStream in)
{
this.in=in;
}
public void setFpath(String p)
{
this.fpath=p;
}
public String getFpath()
{
return fpath;
}
public String getParameter()
{
String r=null;
try
{
r=getParameter(in);
}
catch (Exception e)
{
e.printStackTrace();
}
return r;
}
public long getFileUpload()
{
long r=-1;
try
{
r=getFileUpload(in,fpath);
}
catch (Exception e)
{
e.printStackTrace();
}
return r;
}
public String getParameter(ServletInputStream in)// 只能按顺序提取
throws Exception
{
int l = 0;
byte[] b = new byte[1024];
l = in.readLine(b, 0, b.length);// 依次是读取属性的开始符、名称、属性值的类型、属性的值
String si = new String(b);
if (si.startsWith("----------------------------"))
{// 表示是从开始符开始读，否则应为刚读取文件后的一个属性，此时应少读一次
l = in.readLine(b, 0, b.length);
}
l = in.readLine(b, 0, b.length);
l = in.readLine(b, 0, b.length);
String value = new String(b, 0, l);
return value;
}
public long getFileUpload(ServletInputStream in, String fpath)// 需要提供输入流和存储路径
throws Exception
{
// out.println("文件信息:br>");
long begin = System.currentTimeMillis();// 传送时间计时开始
int l = 0;
byte[] b = new byte[1024];
l = in.readLine(b, 0, b.length);
String sign = new String(b, 0, l);// eg.-----------------------------7d9dd29630a34
l = in.readLine(b, 0, b.length);
String info = new String(b, 0, l);// eg.Content-Disposition:form-data;
// name="file";
l = in.readLine(b, 0, b.length);
// String type=new
// String(b,0,l);//eg.Content-Type:application/octet-stream(程序文件)
l = in.readLine(b, 0, b.length);
// String nulll=new String(b,0,l);//此值应为空
int nIndex = info.toLowerCase().indexOf("filename=\"");
int nLastIndex = info.toLowerCase().indexOf("\"", nIndex + 10);
String filepath = info.substring(nIndex + 10, nLastIndex);
int na = filepath.lastIndexOf("\\");
String filename = filepath.substring(na + 1);
// out.println("文件绝对路径："+filepath+"br>");
// out.println("文件名："+filename+"br>br>");
String path=fpath + filename;
File fi = new File(path);// 建立目标文件
if (!fi.exists()!fi.createNewFile())
return -2;
BufferedOutputStream f = new BufferedOutputStream(new FileOutputStream(
fi));
while ((l = in.readLine(b, 0, b.length)) > 0)
{
if (l == sign.length())
{
String sign1 = new String(b, 0, sign.length());
// out.println(sign1+"br>");
if (sign1.startsWith(sign))// 比对是否文件已传完
break;
}
f.write(b, 0, l);
f.flush();
}
f.flush();
f.close();
long end = System.currentTimeMillis();// 传送时间计时结束
// out.println("上传文件用时："+(end-begin)+"毫秒br>");
return end - begin;
}
}
2. submitFile.jsp：
%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>
%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
html>
head>
base href="%=basePath%>">
title>My JSP 'submitFile.jsp' starting page/title>
meta http-equiv="pragma" content="no-cache">
meta http-equiv="cache-control" content="no-cache">
meta http-equiv="expires" content="0">
meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
meta http-equiv="description" content="This is my page">
!--
link rel="stylesheet" type="text/css" href="styles.css">
-->
script language="javascript">
function check()
{
if (document.form2.name.value==""){
alert("姓名不能为空！！");
document.form2.name.focus();
return false;
}
if (document.form2.file.value==""){
alert("文件不能为空！！");
return false;
}
return true;
}
/script>
/head>
body>
br>
form method="post" name="form2" enctype="MULTIPART/FORM-DATA"
action="AnswerFile.jsp">
br>
p align="center">
nbsp;
br>
/p>
table width="530" border="1" bgcolor="#c0c0c0" align="center"
height="91">
tbody>
tr>
td valign="top" align="right">
姓名
br>
/td>
td valign="top">
input type="text" name="name">
/td>
/tr>
tr>
td align="right">
nbsp; 文件
/td>
td align="left">
nbsp;
input type="file" name="file">
/td>
/tr>
tr>
td valign="top" align="right">
文件类型
br>
/td>
td valign="top" align="left">
select size="1" name="leixing">
option selected value="作业">
作业
/option>
option value="课程设计">
课程设计
/option>
option value="论文">
论文
/option>
/select>
/td>
/tr>
tr>
td align="right">
input type="Submit" value="上传" name="button2" onclick="return(check());">
/td>
td align="left">
nbsp;
input type="reset" value="重置" name="button3">
/td>
/tr>
/tbody>
/table>
p>
nbsp;
br>
br>
nbsp;
/p>
/form>
/body>
/html>
3. AnswerFile.jsp：
%@ page language="java" import="java.util.*,java.io.*"
pageEncoding="GB18030"%>
%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
html>
head>
base href="%=basePath%>">
title>My JSP 'AnswerFile.jsp' starting page/title>
meta http-equiv="pragma" content="no-cache">
meta http-equiv="cache-control" content="no-cache">
meta http-equiv="expires" content="0">
meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
meta http-equiv="description" content="This is my page">
!--
link rel="stylesheet" type="text/css" href="styles.css">
-->
/head>
body>
jsp:useBean id="upload" scope="session" class="FileUpload.FileUpload"/>
jsp:setProperty name="upload" value="C://" property="fpath"/>
%
ServletInputStream in = request.getInputStream();
upload.setInputStream(in);
String nam = upload.getParameter();
out.println("姓名:" + nam + "br>br>");
long time = upload.getFileUpload();
out.println("文件上传完毕，总共耗时：" + time + "毫秒br>");
String leixing = upload.getParameter();
out.println("文件类型：" + leixing + "br>");
in.close();
%>
br>
div align="right">
a href="index.jsp">回到首页/a>
/div>
/body>
/html>
希望本文所述对大家的JSP程序设计有所帮助。
