package ch03.section04;

import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class OperatorServlet
    extends HttpServlet {
  String info;
  String sqlStr;
  static final private String CONTENT_TYPE = "text/html; charset=gb2312";
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws
      ServletException, IOException {
    response.setContentType(CONTENT_TYPE);
    PrintWriter out = response.getWriter();
    DBOperator db = new DBOperator();
    HttpSession session = request.getSession();
    try {
      String flag = request.getParameter("flag");

      if (flag == null) {
        info = "沒有進行任何操作！";
        response.sendRedirect("../ch03/section04/DBinfo.jsp");
        return;
      }
      else if (flag.equals("add")) {
        String studentName = request.getParameter("studentName");
        studentName = new String(studentName.getBytes("8859_1"), "GB2312");
        String studentAge = request.getParameter("studentAge");
        String studentGrade = request.getParameter("studentGrade");
        sqlStr =
            "insert into ch03section04 (studentName,studentAge,studentGrade) values ('" +
            studentName + "'," + studentAge + "," + studentGrade + ")";
        db.executeUpdate(sqlStr, new String("access"));
        info = "數據庫操作成功！";
        session.setAttribute("info", info);
        response.sendRedirect("../ch03/section04/DBinfo.jsp");
        return;
      }
      else if (flag.equals("query")) {
        sqlStr =
            "select studentID,studentName,studentAge,studentGrade from ch03section04 ";
        ResultSet set = db.executeQuery(sqlStr, new String("access"));
        session.setAttribute("set", set);
        response.sendRedirect("../ch03/section04/DBSet.jsp");
        return;
      }
      else {
      }
    }
    catch (Exception ex) {
      info = "數據庫操作不成功！";
      session.setAttribute("info", info);
      response.sendRedirect("../ch03/section04/DBinfo.jsp");
    }
    finally {
    }
  }

  public void doPost(HttpServletRequest request, HttpServletResponse response) throws
      ServletException, IOException {
    doGet(request, response);
  }

  public void destroy() {
  }
}