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how can I open netcdf file in applet?

Dear All:
  I meet some problem and try two ways to resolve it,
  but still can't resolve.
  I hope someone can give me the correct resolve ways....

  Target :
  I want use Applet and NetCDF Java Library (Version 2) to do
      1. open the remote netcdf file(http://61.60.103.48:81/g2var1level.nc, the remote file also in same folder with applet class.)
      2. print size and data of the Variable("lon" & "lat") which in netcdf file.

  I can't get the correct result, but get some error message in Java console :
 
  First  way :
  I use the function in Applet to open the remote file,
  (the function can run in application): 

      String urlfile = "http://61.60.103.48:81/g2var1level.nc";
      NetcdfFile ncfile = NetcdfFile.open(urlfile);
 
  and HTML code use :

      <applet code="MyNetcdfApplet.class" archive="nc2.2.jar" codebase=. width=300 height=400>
      <param name="NCFile" value="http://61.60.103.48:81/g2var1level.nc">
      ...
      </applet>
 
  First way Error message :
   IE version 6.0.2900.2180.xpsp_sp2_gdr.050301-1519
  Java Plug-in 1.5.0_06
  JRE version 1.5.0_06 Java HotSpot(TM) Client VM
 
   java.security.AccessControlException: access denied (java.io.FilePermission http:\61.60.103.48:81\g2var1level.nc read)
  at java.security.AccessControlContext.checkPermission(Unknown Source)
  at java.security.AccessController.checkPermission(Unknown Source)
  at java.lang.SecurityManager.checkPermission(Unknown Source)
  at java.lang.SecurityManager.checkRead(Unknown Source)
  at java.io.File.exists(Unknown Source)
  at ucar.nc2.N3iosp.open(N3iosp.java:93)
  at ucar.nc2.NetcdfFile.<init>(NetcdfFile.java:780)
  at ucar.nc2.NetcdfFile.open(NetcdfFile.java:339)
  at ucar.nc2.NetcdfFile.open(NetcdfFile.java:221)
  at ucar.nc2.NetcdfFile.open(NetcdfFile.java:167)
  at ucar.nc2.NetcdfFile.open(NetcdfFile.java:151)
  at MyNetcdfApplet.init(MyNetcdfApplet.java:29)
  at sun.applet.AppletPanel.run(Unknown Source)
  at java.lang.Thread.run(Unknown Source)
     
   Second  way :
   I change my code in Applet to open the remote file,
 
       String urlfile = getParameter("NCFile");            
       URL url = "" URL(getCodeBase(), urlfile);
       NetcdfFile ncfile = new NetcdfFile(url);
 
  and HTML code use :

      <applet code="MyNetcdfApplet.class" archive="nc2.2.jar" codebase=. width=300 height=400>
      <param name="NCFile" value="/g2var1level.nc">
      ...
      </applet>
 
 Second way Error message :
 URL http://61.60.103.48:81/g2var1level.nc
 java.security.AccessControlException: access denied (java.io.FilePermission http:\61.60.103.48:81\g2var1level.nc read)
 at java.security.AccessControlContext.checkPermission(Unknown Source)
 at java.security.AccessController.checkPermission(Unknown Source)
 at java.lang.SecurityManager.checkPermission(Unknown Source)
 at java.lang.SecurityManager.checkRead(Unknown Source)
 at java.io.File.exists(Unknown Source)
 at ucar.nc2.N3iosp.open(N3iosp.java:93)
 at ucar.nc2.NetcdfFile.<init>(NetcdfFile.java:763)
 at MyNetcdfApplet.init(MyNetcdfApplet.java:33)
 at sun.applet.AppletPanel.run(Unknown Source)
 at java.lang.Thread.run(Unknown Source)
 
And I didn't sign My applet. Could anyone tell me what keypoint  I miss?
(May I need sign it? or not add some import jar file?)
 
How can I do that My applet can read the remote netcdf file?
The netcdf file also be in My applet class folder.
First way or Second way is better?
 
Thank you very much~
 
                                                                                    Monica