使用输出流在Java servlet中打印出一个变量

public class DemoServlet extends HttpServlet {

    public void service(HttpServletRequest req, HttpServletResponse resp)
        throws IOException, ServletException {

        //prints out my string
        resp.getOutputStream().write(\"Hello from servlet\\n\".getBytes());

        String variable =\"VAR\";
        //trying to print out variable by this way but doesn\'t work
        resp.getOutputStream().write(\"%s\\n\".getBytes(),variable);
        //doesn\'t work this way either
        resp.getOutputStream().write(\"variable is:\"+ variable +\"something else\\n\".getBytes());
    }
}

PageWriter out= resp.getWriter();

ServletOutputStream

public void makedbconnection() {
    try {
        Class.forName(\"com.mysql.jdbc.Driver\").newInstance();
        Dbcon = DriverManager.getConnection(\"jdbc:mysql://localhost/test\");
    } catch(Exception idc) {
       //ON THIS LINE, out is ServletOutputStream.
       idc.printStackTrace(out);
    }
    //System.out.println(\"connection made\");
}