一个文件上传bean

package com.upload; 

import java.io.*; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.ServletInputStream; 
import javax.servlet.ServletException; 

public class upload{ 
private static String newline = ""; 
private String uploadDirectory = "."; 
private String ContentType = ""; 
private String CharacterEncoding = ""; 

private String getFileName(String s){ 
int i = s.lastIndexOf(""); 
if(i < 0 // i >= s.length() - 1){ 
i = s.lastIndexOf("/"); 
if(i < 0 // i >= s.length() - 1) 
return s; 
} 
return s.substring(i + 1); 
} 

public void setUploadDirectory(String s){ 
uploadDirectory = s; 
} 

public void setContentType(String s){ 
ContentType = s; 
int j; 
if((j = ContentType.indexOf("boundary=")) != -1){ 
ContentType = ContentType.substring(j + 9); 
ContentType = "--" + ContentType; 
} 
} 

public void setCharacterEncoding(String s){ 
CharacterEncoding = s; 
} 

public void uploadFile( HttpServletRequest req) throws ServletException, IOException{ 
setCharacterEncoding(req.getCharacterEncoding()); 
setContentType(req.getContentType()); 
uploadFile(req.getInputStream()); 
} 

public void uploadFile( ServletInputStream servletinputstream) throws ServletException, IOException{ 

String s5 = null; 
String filename = null; 
byte Linebyte[] = new byte[4096]; 
byte outLinebyte[] = new byte[4096]; 
int ai[] = new int[1]; 
int ai1[] = new int[1]; 

String line; 
//得到文件名 
while((line = readLine(Linebyte, ai, servletinputstream, CharacterEncoding)) != null){ 
int i = line.indexOf("filename="); 
if(i >= 0){ 
line = line.substring(i + 10); 
if((i = line.indexOf(""")) > 0) 
line = line.substring(0, i); 
break; 
} 
} 

filename = line; 

if(filename != null && !filename.equals(""")){ 
filename = getFileName(filename); 

String sContentType = readLine(Linebyte, ai, servletinputstream, CharacterEncoding); 
if(sContentType.indexOf("Content-Type") >= 0) 
readLine(Linebyte, ai, servletinputstream, CharacterEncoding); 

//File(String parent, String child) 
//Creates a new File instance from a parent pathname string 
//and a child pathname string. 
File file = new File(uploadDirectory, filename); 

//FileOutputStream(File file) 
//Creates a file output stream to write to the file represented 
//by the specified File object. 
FileOutputStream fileoutputstream = new FileOutputStream(file); 

while((sContentType = readLine(Linebyte, ai, servletinputstream, CharacterEncoding)) != null){ 
if(sContentType.indexOf(ContentType) == 0 && Linebyte[0] == 45) 
break; 

if(s5 != null){ 
//write(byte[] b, int off, int len) 
//Writes len bytes from the specified byte array starting 
//at offset off to this file output stream. 
fileoutputstream.write(outLinebyte, 0, ai1[0]); 
fileoutputstream.flush(); 
} 
s5 = readLine(outLinebyte, ai1, servletinputstream, CharacterEncoding); 
if(s5 == null // s5.indexOf(ContentType) == 0 && outLinebyte[0] == 45) 
break; 
fileoutputstream.write(Linebyte, 0, ai[0]); 
fileoutputstream.flush(); 
} 

byte byte0; 
if(newline.length() == 1) 
byte0 = 2; 
else 
byte0 = 1; 
if(s5 != null && outLinebyte[0] != 45 && ai1[0] > newline.length() * byte0) 
fileoutputstream.write(outLinebyte, 0, ai1[0] - newline.length() * byte0); 
if(sContentType != null && Linebyte[0] != 45 && ai[0] > newline.length() * byte0) 
fileoutputstream.write(Linebyte, 0, ai[0] - newline.length() * byte0); 

fileoutputstream.close(); 
} 
} 

private String readLine(byte Linebyte[], int ai[], 
ServletInputStream servletinputstream, 
String CharacterEncoding){ 
try{ 
//readLine(byte[] buffer, int offset, int length) 
//Reads a line from the POST data. 
ai[0] = servletinputstream.readLine(Linebyte, 0, Linebyte.length); 
if(ai[0] == -1) 
return null; 
}catch(IOException _ex){ 
return null; 
} 
try{ 
if(CharacterEncoding == null){ 
//用缺省的编码方式把给定的byte数组转换为字符串 
//String(byte[] bytes, int offset, int length) 
return new String(Linebyte, 0, ai[0]); 
}else{ 
//用给定的编码方式把给定的byte数组转换为字符串 
//String(byte[] bytes, int offset, int length, String enc) 
return new String(Linebyte, 0, ai[0], CharacterEncoding); 
} 
}catch(Exception _ex){ 
return null; 
} 
} 
/* 
public int readLine(byte[] buffer, 
int offset, 
int length) throws java.io.IOException 
从POST来的数据中读一行 
参数: 
buffer - buffer to hold the line data 
offset - offset into the buffer to start 
length - maximum number of bytes to read. 
Returns: 
number of bytes read or -1 on the end of line. 
*/ 
} 

upload.jsp 
< import="com.upload.upload"%> 
<% 
String Dir = "/home/tonywan/upload"; 

upload upload = new upload(); 
upload.setUploadDirectory(Dir); 
upload.uploadFile(request); 
out.print("成功上载文件至" + Dir + ""); 
%> 

upload.html 
File upload test