import java.io.File;  
import java.io.FileInputStream;  
import java.io.FileNotFoundException;  
import java.io.FileOutputStream;  
import java.io.IOException;  
import java.io.InputStream;  
import java.io.OutputStream;  
  
  
public class Test {  
  
    public static void main(String[] args) {  
        try {  
            InputStream is = request.getInputStream();  
              
            File filedir = new File("服务器绝对路径文件夹常量");  
            if (!filedir.exists())  
            	filedir.mkdirs();
            File file = new File(filedir, "文件名.后缀名");  
            OutputStream os = new FileOutputStream(file);
              
            byte[] byteStr = new byte[1024];  
            int len = 0;  
            while ((len = is.read(byteStr)) > 0) {  
                os.write(byteStr,0,len);  
            }  
            is.close();  
              
            os.flush();  
            os.close();