This article describes how JSP implements fast uploading of files. Share it for your reference. The details are as follows:
Here we demonstrate that JSP does not use third-party libraries to realize the function of quickly uploading files
1. ：
package FileUpload;
import ;
import ;
import ;
import ;
/**
*
*/
/**
* @author Qch
*
*/
public class FileUpload
{
ServletInputStream in=null;
String fpath="C://";
public FileUpload()
{
fpath="C://";
in=null;
}
public void setInputStream(ServletInputStream in)
{
=in;
}
public void setFpath(String p)
{
=p;
}
public String getFpath()
{
return fpath;
}
public String getParameter()
{
String r=null;
try
{
r=getParameter(in);
}
catch (Exception e)
{
();
}
return r;
}
public long getFileUpload()
{
long r=-1;
try
{
r=getFileUpload(in,fpath);
}
catch (Exception e)
{
();
}
return r;
}
public String getParameter(ServletInputStream in)// Only extracted in order throws Exception
{
int l = 0;
byte[] b = new byte[1024];
l = (b, 0, );// The start character of the property is read, name, type of attribute value, and value of attribute String si = new String(b);
if (("----------------------------"))
{// means that it starts reading from the start character, otherwise it should be a property after the file is just read. You should read it less at this time l = (b, 0, );
}
l = (b, 0, );
l = (b, 0, );
String value = new String(b, 0, l);
return value;
}
public long getFileUpload(ServletInputStream in, String fpath)// Input stream and storage path are required throws Exception
{
// ("File Information:<br>"); long begin = ();// The transmission time starts int l = 0;
byte[] b = new byte[1024];
l = (b, 0, );
String sign = new String(b, 0, l);// eg.-----------------------------7d9dd29630a34
l = (b, 0, );
String info = new String(b, 0, l);// -Disposition:form-data;
// name="file";
l = (b, 0, );
// String type=new
// String(b,0,l);//-Type:application/octet-stream(program file) l = (b, 0, );
// String nulll=new String(b,0,l);//This value should be empty int nIndex = ().indexOf("filename=\"");
int nLastIndex = ().indexOf("\"", nIndex + 10);
String filepath = (nIndex + 10, nLastIndex);
int na = ("\\");
String filename = (na + 1);
// ("Absolute path of file: "+filepath+"<br>"); // ("Filename: "+filename+"<br><br>"); String path=fpath + filename;
File fi = new File(path);// Create target file if (!()&&!())
return -2;
BufferedOutputStream f = new BufferedOutputStream(new FileOutputStream(
fi));
while ((l = (b, 0, )) > 0)
{
if (l == ())
{
String sign1 = new String(b, 0, ());
// (sign1+"<br>");
if ((sign))// Compare whether the file has been transmitted break;
}
(b, 0, l);
();
}
();
();
long end = ();// The transmission time ends // ("Uploading the file time: "+(end-begin)+"ms<br>"); return end - begin;
}
}
2. ：
<%@ page language="java" import=".*" pageEncoding="GB18030"%>
<%
String path = ();
String basePath = () + "://"
+ () + ":" + ()
+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My 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="">
-->
<script language="javascript">
function check()
{
if (document.==""){
alert("The name cannot be empty!!");
document.();
return false;
}
if (document.==""){
alert("The file cannot be empty!!");
return false;
}
return true;
}
</script>
</head>
<body>
<br>
<form method="post" name="form2" enctype="MULTIPART/FORM-DATA"
action="">
<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">
Name
<br>
</td>
<td valign="top">
<input type="text" name="name">
</td>
</tr>
<tr>
<td align="right">
&nbsp; document
</td>
<td align="left">
&nbsp;
<input type="file" name="file">
</td>
</tr>
<tr>
<td valign="top" align="right">
document类型
<br>
</td>
<td valign="top" align="left">
<select size="1" name="leixing">
<option selected value="Operation">
Operation
</option>
<option value="Course Design">
Course Design
</option>
<option value="paper">
paper
</option>
</select>
</td>
</tr>
<tr>
<td align="right">
<input type="Submit" value="Upload" name="button2" onclick="return(check());">
</td>
<td align="left">
&nbsp;
<input type="reset" value="Reset" name="button3">
</td>
</tr>
</tbody>
</table>
<p>
&nbsp;
<br>
<br>
&nbsp;
</p>
</form>
</body>
</html>
3. ：
<%@ page language="java" import=".*,.*"
pageEncoding="GB18030"%>
<%
String path = ();
String basePath = () + "://"
+ () + ":" + ()
+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My 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="">
-->
</head>
<body>
<jsp:useBean scope="session" class=""/>
<jsp:setProperty name="upload" value="C://" property="fpath"/>
<%
ServletInputStream in = ();
(in);
String nam = ();
("Name:" + nam + "<br><br>");
long time = ();
("The file is uploaded, and it takes a total of time:" + time + "Milliseconds<br>");
String leixing = ();
("File Type:" + leixing + "<br>");
();
%>
<br>
<div align="right">
<a href="">Back to homepage</a>
</div>
</body>
</html>
I hope this article will be helpful to everyone's JSP programming.