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    SERVLET是最基础的控制框架，其文件上传部分也是比较基础的函数累计 比较考验基础，先给出文件上传功能代码 供各位参考

    本流程 依赖JAR包    

    commons-io-2.4.jar     依赖JAR包资源下载 .zip

    commons-fileupload-1.2.1.jar

        private final int BUFFERSIZE = 1024 * 8;

private final String splitLine = File.separator;

private String tempAttachmentFileName;

        //POST函数处理  文本字段  文件混合上传 处理函数

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

// 计算能够上传附件的大小

int maxLen = 7 * 1024 * 1024;

String attachmentPath = "D:/upfile/";

// 得到附件

ServletOutputStream out = response.getOutputStream();

int contentLen = request.getContentLength();

if (contentLen < maxLen) {

String contentType = request.getContentType();

String boundary = getBoundary(contentType);

ServletInputStream in = request.getInputStream();

FileOutputStream fou = null;

byte[] b = new byte[BUFFERSIZE];

int result;

try {

result = in.readLine(b, 0, b.length); // 读取boundary

result = in.readLine(b, 0, b.length); // 读取Content-Disposition

String upLoadFileName = getUpLoadFileName(new String(b, 0,

result));

tempAttachmentFileName = upLoadFileName;

File  ftemp = new File(attachmentPath + upLoadFileName);

if(ftemp.exists() == false){

ftemp.createNewFile();

}

fou = new FileOutputStream(attachmentPath + upLoadFileName);

result = in.readLine(b, 0, b.length); // 读取Content-Type;

result = in.readLine(b, 0, b.length); // 读取空行;

int totalRead = 0;

result = in.readLine(b, 0, b.length);

while ((new String(b, 0, result)).trim().indexOf(boundary) == -1) {

totalRead += result;

fou.write(b, 0, result);

result = in.readLine(b, 0, b.length);

}

out.println(totalRead);

fou.close();

in.close();

// 处理文件

dealFile(upLoadFileName, totalRead, attachmentPath);

} catch (Exception ex) {

System.out.print(ex.toString());

}

}

}

/*

* 得到filename

*/

private String getUpLoadFileName(String line) {

int split = line.indexOf("name=");

String tempFileName = delQuote(line.substring(split + 9, line.length())

.trim());

if (tempFileName.indexOf("\\") != -1) {

tempFileName = tempFileName.substring(tempFileName

.lastIndexOf("\\") + 1, tempFileName.length());

}

return tempFileName;

}

/*

* 得到分隔符

*/

private String getBoundary(String line) {

return line.substring(line.indexOf("boundary=") + 9, line.length())

.trim();

}

/*

* 去除""

*/

private String delQuote(String line) {

if (line.indexOf("\"") != -1) {

line = line.substring(1, (line.length() - 1));

}

return line;

}

/*

* 处理文件，把最后的两个字节删除

*/

private void dealFile(String fileName, int totalRead, String attachmentPath)

throws IOException {

File file = new File(attachmentPath + tempAttachmentFileName);

byte[] b = new byte[totalRead - 2];

RandomAccessFile rafRead = new RandomAccessFile(file, "r");

rafRead.readFully(b, 0, totalRead - 2);

rafRead.close();

file.delete();

RandomAccessFile rafWrite = new RandomAccessFile(attachmentPath

+ fileName, "rw");

rafWrite.write(b);

rafWrite.close();

}

如有疑问 请留言 欢迎提供建议