项目需求,需要在板子上写一个mini的web项目,由于空间的有限(大概4M)并且项目中有文件上传的功能,所以就选择用servlet实现.

大体步骤就是:  解析request头信息    获取数据流  输入到指定目录 , 但实现的功能有个很严重的缺陷,就是全部将数据流读出来,没有缓存.

导致服务器内存爆满,没有办法读取大的数据流,所以也就放弃了用这种方法实现.具体的方法如下,如有更好的办法,请大家指点一下.

import java.io.BufferedReader;

import java.io.DataInputStream;

import java.io.DataOutputStream;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.StringReader;

import java.util.Iterator;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import com.meeboss.meestorage.bean.MeeFile;

/**

* 文件操作副助类

*

*/

public class FileUtil {

/**

* 上传文件到指定目录 并返回文件信息(文件名,大小)

*

* @param request

* @return

*/

public static MeeFile uploadFileToDest1(HttpServletRequest request,

String dest) {

final int NONE = 0;

final int DATAHEADER = 1;

final int FILEDATA = 2;

final int FIELDDATA = 3;

// 将请求消息的实体送到b变量中

int TotalBytes = request.getContentLength();

byte[] b = new byte[TotalBytes];

String contentType = request.getContentType();// 请求消息类型

String filename = ""; // 文件名

String boundary = ""; // 分界符

String lastboundary = ""; // 结束符

int filesize = 0; // 文件长度

int pos = contentType.indexOf("boundary=");

if (pos != -1) {// 取得分界符和结束符

pos += "boundary=".length();

boundary = "--" + contentType.substring(pos);

lastboundary = boundary + "--";

}

int state = NONE;

// 得到数据输入流reqbuf

try {

DataInputStream in = new DataInputStream(request.getInputStream());

in.readFully(b);

in.close();

String reqContent = new String(b, "UTF-8");

BufferedReader reqbuf = new BufferedReader(new StringReader(

reqContent));

boolean flag = true;

while (flag == true) {

String s = reqbuf.readLine();

if ((s == lastboundary) || (s == null))

break;

switch (state) {

case NONE:

if (s.startsWith(boundary)) {

state = DATAHEADER;

}

break;

case DATAHEADER:

pos = s.indexOf("filename=");

if (pos == -1) {// 将表单域的名字解析出来

pos = s.indexOf("name=");

pos += "name=".length() + 1;

s = s.substring(pos);

int l = s.length();

s = s.substring(0, l - 1);

state = FIELDDATA;

} else {// 将文件名解析出来

String temp = s;

pos = s.indexOf("filename=");

pos += "filename=".length() + 1;

s = s.substring(pos);

int l = s.length();

s = s.substring(0, l - 1);

pos = s.lastIndexOf("\\");

s = s.substring(pos + 1);

filename = s;

// 从字节数组中取出文件数组

pos = byteIndexOf(b, temp, 0);

b = subBytes(b, pos + temp.getBytes().length + 2,

b.length);// 去掉前面的部分

s = reqbuf.readLine();

b = subBytes(b, s.getBytes().length + 4, b.length);

pos = byteIndexOf(b, boundary, 0);

b = subBytes(b, 0, pos - 1);

File f = new File(dest, filename); // 写入文件

DataOutputStream fileout = new DataOutputStream(

new FileOutputStream(f));

fileout.write(b, 0, b.length - 1);

filesize = b.length - 1;

state = FILEDATA;

}

break;

case FIELDDATA:

s = reqbuf.readLine();

state = NONE;

break;

case FILEDATA:

while ((!s.startsWith(boundary))

&& (!s.startsWith(lastboundary))) {

s = reqbuf.readLine();

if (s.startsWith(boundary)) {

state = DATAHEADER;

break;

}

}

break;

}

}

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

// 指定输出类型

MeeFile meeFile = new MeeFile();

meeFile.setName(filename);

meeFile.setLength(String.valueOf(filesize));

return meeFile;

}

/**

* 字节数组中的INDEXOF函数，与STRING类中的INDEXOF类似

*

* @param b

* @param s

* @param start

* @return

*/

private static int byteIndexOf(byte[] b, String s, int start) {

return byteIndexOf(b, s.getBytes(), start);

}

/**

* 字节数组中的INDEXOF函数，与STRING类中的INDEXOF类似

*

* @param b

* @param s

* @param start

* @return

*/

private static int byteIndexOf(byte[] b, byte[] s, int start) {

int i;

if (s.length == 0) {

return 0;