用JAVA语言如何在服务器上把一个inputstream生产一个文件。(50分)

我在服务器上得到了yige 一个二进制的流式变量，
InputStream temp_inputstream,怎样在服务器上生产一个文件呢？
高手指点迷津。

FileInputStream

public void SaveStream(InputStream inputstream) throws IOException{
String CharacterEncoding="ISO-8859-1";
byte Linebyte[] = new byte[1024];
int ai[] = new int[1];
File file = new File(uploadpath, FileName);
FileOutputStream fileoutputstream = new FileOutputStream(file);
String s = null;
do
{
if (s!=null){
fileoutputstream.write(Linebyte, 0, ai[0]);
fileoutputstream.flush();
}
try {
ai[0] = servletinputstream.read(Linebyte, 0, Linebyte.length);
}
catch (weblogic.utils.NestedRuntimeException se) {
System.out.print("Save File Error!/n");
}
if (ai[0]<0){
break;
}
s = new String(Linebyte, 0, ai[0], CharacterEncoding);
long l = Long.parseLong(String.valueOf(s.length()));
servletinputstream.skip(l);
}while(true);
inputstream.close();
fileoutputstream.close();
}

如果看不懂的话！我来解释解释
File file = new File(uploadpath, FileName);//建立一个File对象
//建立一个文件输出流
FileOutputStream fileoutputstream = new FileOutputStream(file);
// 挨个读取文件的字节
fileoutputstream.write(Linebyte, 0, ai[0]);
//写入文件
fileoutputstream.flush();