java 获取注册表键值

    /**
     *
     * @param location path in the registry
     * @param key registry key
     * @return registry value or null if not found
     */

public static final String readRegistry(String location, String key)
{
  try
  {
      // Run reg query, then read output with StreamReader (internal class)
      Process process = Runtime.getRuntime().exec("reg query " +
              '"'+ location + "\" /v " + key);

      InputStream is = process.getInputStream();
      StringBuilder sw = new StringBuilder();

      try
      {
         int c;
         while ((c = is.read()) != -1)
             sw.append((char)c);
      }
      catch (IOException e)
      {
      }

      String output = sw.toString();

      // Output has the following format:
      // \n<Version information>\n\n<key>    <registry type>    <value>\r\n\r\n
      int i = output.indexOf("REG_SZ");
      if (i == -1)
      {
          return null;
      }

      sw = new StringBuilder();
      i += 6; // skip REG_SZ

      // skip spaces or tabs
      for (;;)
      {
         if (i > output.length())
             break;
         char c = output.charAt(i);
         if (c != ' ' && c != '\t')
             break;
         ++i;
      }

      // take everything until end of line
      for (;;)
      {
         if (i > output.length())
             break;
         char c = output.charAt(i);
         if (c == '\r' || c == '\n')
             break;
         sw.append(c);
         ++i;
      }

      return sw.toString();
  }
  catch (Exception e)
  {
      return null;
  }