java : jdbc PreparedStatement

import java.sql.*;

public class Query1 {
public static void main(String[] args){
String code;
String city;
String sh;
String cname;

if (args.length ==1){
code = args[0];
city = code.substring(0,4)+"00";
sh = code.substring(0,2)+"0000";
} else {
System.out.println(" usage: java Query2 ?????? ");
return;
}
try{
Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;

DriverManager.registerDriver(new com.mysql.jdbc.Driver());
String url = "jdbc:mysql://localhost:3306/test";
conn = DriverManager.getConnection(url,"user","pass");
String sql = "select code,cname from table where code in (?,?,?)";
stmt = conn.prepareStatement(sql);
stmt.setString(1, sh);
stmt.setString(2, city);
stmt.setString(3, code);
rs = stmt.executeQuery();

while(rs.next()){
code = rs.getString(1);
cname = rs.getString(2);
System.out.println(code+" "+cname);
}
rs.close();
stmt.close();
conn.close();
}
catch (Exception e){
System.out.println(e);
}
}

}