经典java转码程序，有备无患！实现和 jdk\bin\native2ascii.exe 同样的功能

private string convert(string str)
{
string tmp;
stringbuffer sb = new stringbuffer(1000);
char c;
int i, j;
sb.setlength(0);
for(i = 0;i<str.length();i++){
c = str.charat(i);
if (c > 255) {
sb.append("\\u");
j = (c >>> 8);
tmp = integer.tohexstring(j);
if (tmp.length() == 1) sb.append("0");
sb.append(tmp);
j = (c & 0xff);
tmp = integer.tohexstring(j);
if (tmp.length() == 1) sb.append("0");
sb.append(tmp);
}
else {
sb.append(c);
}

}return(new string(sb));
}