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"));

%>