如何接受XMLHttpRequest传输过来的文件

Question

如何将上图中选中的文件流保存到本地

Answer 1

 String contentType = request.getContentType();
try{
if(contentType.indexOf("multipart/form-data") >= 0){
//读入上传的数据
in = new DataInputStream(request.getInputStream());
int formDataLength = request.getContentLength();
if(formDataLength > MAX_SIZE){
out.println("<P>上传的文件字节数不可以超过" + MAX_SIZE + "</p>");
return;
}
//保存上传文件的数据
byte dataBytes[] = new byte[formDataLength];
int byteRead = 0;
int totalBytesRead = 0;
//上传的数据保存在byte数组
while(totalBytesRead < formDataLength){
byteRead = in.read(dataBytes,totalBytesRead,formDataLength);
totalBytesRead += byteRead;
}
//根据byte数组创建字符串
String file = new String(dataBytes);
//out.println(file);
//取得上传的数据的文件名
String saveFile = file.substring(file.indexOf("filename=\"") + 10);
saveFile = saveFile.substring(0,saveFile.indexOf("\n"));
saveFile = saveFile.substring(saveFile.lastIndexOf("\\") + 1,saveFile.indexOf("\""));
int lastIndex = contentType.lastIndexOf("=");
//取得数据的分隔字符串
String boundary = contentType.substring(lastIndex + 1,contentType.length());
//创建保存路径的文件名
String fileName = rootPath + saveFile;
//out.print(fileName);
int pos;
pos = file.indexOf("filename=\"");
pos = file.indexOf("\n",pos) + 1;
pos = file.indexOf("\n",pos) + 1;
pos = file.indexOf("\n",pos) + 1;
int boundaryLocation = file.indexOf(boundary,pos) - 4;
//out.println(boundaryLocation);
//取得文件数据的开始的位置
int startPos = ((file.substring(0,pos)).getBytes()).length;
//out.println(startPos);
//取得文件数据的结束的位置
int endPos = ((file.substring(0,boundaryLocation)).getBytes()).length;
//out.println(endPos);
//检查上载文件是否存在
File checkFile = new File(fileName);
if(checkFile.exists()){
out.println("<p>" + saveFile + "文件已经存在.</p>");
}
//检查上载文件的目录是否存在
File fileDir = new File(rootPath);
if(!fileDir.exists()){
fileDir.mkdirs();
}
//创建文件的写出类
fileOut = new FileOutputStream(fileName);
//保存文件的数据
fileOut.write(dataBytes,startPos,(endPos - startPos));
fileOut.close();
}