从网上当了一个例子，发觉上传图片文件时图片文件中内容发生了变化，最大的变化时所有的FF变成了3F
也就是说输出时把字符当成有符号传送了？（是这样把？）
使用代码如下：
PrintWriter pw = new PrintWriter(new BufferedWriter(new
FileWriter((savePath==null? "" : savePath) + filename)));
while (i != -1 && !newLine.startsWith(boundary)) {
// 文件内容的最后一行包含换行字符
// 因此我们必须检查当前行是否是最
// 后一行
i = in.readLine(line, 0, 1280);
if ((i==boundaryLength+2 || i==boundaryLength+4)
&& (new String(line, 0, i).startsWith(boundary)))
pw.print(newLine.substring(0, newLine.length()-2));
else
pw.print(newLine);
newLine = new String(line, 0, i);
}
pw.close();
但是总是不行，后来我把PrintWriter用FileOutputStream替代,代码如下：
FileOutputStream pw=new FileOutputStream((savePath==null? "" : savePath) + filename);
//PrintWriter pw = new PrintWriter(new BufferedWriter(new
//FileWriter((savePath==null? "" : savePath) + filename)));
while (i != -1 && !newLine.startsWith(boundary)) {
// 文件内容的最后一行包含换行字符
// 因此我们必须检查当前行是否是最
// 后一行
i = in.readLine(line, 0, 1280);
if ((i==boundaryLength+2 || i==boundaryLength+4)
&& (new String(line, 0, i).startsWith(boundary)))
pw.write(newLine.substring(0, newLine.length()-2).getBytes("ISO8859_1"));
else
pw.write(newLine.getBytes("ISO8859_1"));
newLine = new String(line, 0, i,"ISO8859_1");
}
pw.close();
竟然就可以了，那个转换的编码还一定要上才行，不然也不干活的，真是郁闷，这跨平台就不能让写CODE的人解放解放，一个输出都N多类，看着心寒，想着简直想死啊
哎 忙了我一个下午，原来就是这回事
下面把原代码附上，是把别人的代码改吧改吧放上来的，还请原作者不要见意：
Java bean 文件：
package cr.web;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.ServletInputStream;
import java.util.Dictionary;
import java.util.Hashtable;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.*;
public class FileUploadBean {
private String savePath, filepath, filename, contentType;
private byte[] b;
byte t;
private Dictionary fields;
public String getFilename() {
return filename;
}
public String getFilepath() {
return filepath;
}
public void setSavePath(String savePath) {
this.savePath = savePath;
}
public String getContentType() {
return contentType;
}
public String getFieldValue(String fieldName) {
if (fields == null || fieldName == null)
return null;
return (String) fields.get(fieldName);
}
private void setFilename(String s) {
if (s==null)
return;
int pos = s.indexOf("filename=\"");
if (pos != -1) {
filepath = s.substring(pos+10, s.length()-1);
// Windows浏览器发送完整的文件路径和名字
// 但Linux/Unix和Mac浏览器只发送文件名字
pos = filepath.lastIndexOf("\\");
if (pos != -1)
filename = filepath.substring(pos + 1);
else
filename = filepath;
}
}
private void setContentType(String s) {
if (s==null)
return;
int pos = s.indexOf(": ");
if (pos != -1)
contentType = s.substring(pos+2, s.length());
}
public void getByte(HttpServletRequest request)
{
DataInputStream is;
int i=0;
try
{
is=new DataInputStream(request.getInputStream());
b=new byte[request.getContentLength()];
while (true)
{
try
{
t=is.readByte();
b[i]=t;
i++;
}
catch(EOFException e)
{ break;}
}
is.close();}
catch(IOException e)
{}
}
public void doUpload1(HttpServletRequest request) throws
IOException {
byte[] line=new byte[128];
FileOutputStream os=new FileOutputStream("c:\\Demo.out");
ServletInputStream in = request.getInputStream();
getByte(request);
String temp="";
temp=new String(b,"ISO8859_1");
byte[] img=temp.getBytes("ISO8859_1");
for (int i=0;i<img.length;i++)
{ os.write(img[i]); }
os.close();
}
public void doUpload(HttpServletRequest request) throws IOException {
request.setCharacterEncoding("GB2312");
ServletInputStream in = request.getInputStream();
byte[] line = new byte[1280];
int i = in.readLine(line, 0, 1280);
if (i < 3)
return;
int boundaryLength = i - 2;
String boundary = new String(line, 0, boundaryLength); //-2丢弃换行字符
fields = new Hashtable();
while (i != -1) {
String newLine = new String(line, 0, i);
if (newLine.startsWith("Content-Disposition: form-data; name=\"")) {
if (newLine.indexOf("filename=\"") != -1) {
setFilename(new String(line, 0, i-2));
if (filename==null)
return;
//文件内容
i = in.readLine(line, 0, 1280);
setContentType(new String(line, 0, i-2));
i = in.readLine(line, 0, 1280);
//空行
i = in.readLine(line, 0, 1280);
newLine = new String(line, 0, i,"ISO8859_1");
FileOutputStream pw=new FileOutputStream((savePath==null? "" : savePath) + filename);
//PrintWriter pw = new PrintWriter(new BufferedWriter(new
//FileWriter((savePath==null? "" : savePath) + filename)));
while (i != -1 && !newLine.startsWith(boundary)) {
// 文件内容的最后一行包含换行字符
// 因此我们必须检查当前行是否是最
// 后一行
i = in.readLine(line, 0, 1280);
if ((i==boundaryLength+2 || i==boundaryLength+4)
&& (new String(line, 0, i).startsWith(boundary)))
pw.write(newLine.substring(0, newLine.length()-2).getBytes("ISO8859_1"));
else
pw.write(newLine.getBytes("ISO8859_1"));
newLine = new String(line, 0, i,"ISO8859_1");
}
pw.close();
}
else {
// 普通表单输入元素
// 获取输入元素名字
int pos = newLine.indexOf("name=\"");
String fieldName = newLine.substring(pos+6, newLine.length()-3);
i = in.readLine(line, 0, 1280);
i = in.readLine(line, 0, 1280);
newLine = new String(line, 0, i);
StringBuffer fieldValue = new StringBuffer(1280);
while (i != -1 && !newLine.startsWith(boundary)) {
// 最后一行包含换行字符
// 因此我们必须检查当前行是否是最后一行
i = in.readLine(line, 0, 1280);
if ((i==boundaryLength+2 || i==boundaryLength+4)
&& (new String(line, 0, i).startsWith(boundary)))
fieldValue.append(newLine.substring(0, newLine.length()-2));
else
fieldValue.append(newLine);
newLine = new String(line, 0, i);
}
fields.put(fieldName, fieldValue.toString());
}
}
i = in.readLine(line, 0, 1280);
}
}
}
HTML页面：
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>文件上载</title>
</head>
<body>
<form action=jsp1.jsp enctype="MULTIPART/FORM-DATA" method=post>
作者: <input type=text name=author>
<br>
公司: <input type=text name=company>
<br>
说明: <textarea name=comment></textarea>
<br>
选择要上载的文件<input type=file name=filename>
<br>
文件描述: <input type=text name=description>
<br>
<input type=submit value="Upload">
</form>
</body>
</html>
JSP页面：
<%@ page contentType="text/html;charset=gb2312"%>
<jsp:useBean id="TheBean" scope="page" class="cr.web.FileUploadBean" />
<%
TheBean.setSavePath("d:\\");
//TheBean.doUpload1(request);
TheBean.doUpload(request);
out.println("Filename:" + TheBean.getFilename());
out.println("<BR>内容类型:" + TheBean.getContentType());
out.println("<BR>作者:" + TheBean.getFieldValue("Author"));
out.println("<BR>公司:" + TheBean.getFieldValue("Company"));
out.println("<BR>说明:" + TheBean.getFieldValue("Comment"));
%>