急：哪位有把Unicode转化成GB的源码？

Question

public class Unicode2GB
{
public Unicode2GB()
{
}
public static String decode(String s)
{
StringBuffer sb = new StringBuffer();
                boolean escape = false;
               for(int i=0; i<s.length(); i++)
               {
                     char c = s.charAt(i);
                     switch (c)
                     {
                        case '\\':
                    escape = true;
                    break;
                        case 'u':
                        case 'U':
                        if (escape)
                        {
                         try
                          {
                                 sb.append((char)Integer.parseInt(
                                         s.substring(i+1,i+5),16));
                                 escape = false;
                           }
                           catch (NumberFormatException e) {
                                 throw new IllegalArgumentException();
                           }
                           i += 4;
                       }
                       else
                      { 
                         sb.append(c);
                       }
                       break;
                     default:
                       sb.append(c);
                       break;
                    }
          }          return sb.toString();
   } public static void main(String[] args) throws IOException
{
System.out.println("Please input string to be translated");
String oldStr = null;
BufferedReader in = new BufferedReader(new InputStreamReader
                     (System.in));
while(true)
{
oldStr = in.readLine(); 
System.out.println(Unicode2GB.decode(oldStr));
}
}

}