Servlet) 예제(단순 알림 or 객체 전달)

<연산을 통해 알림을 받을 때>-> script로 alert전달

<form name="f" action="MemoServlet" method="post" id="f">

cf) action에서 매핑값을 설정

@WebServlet("/MemoServlet")

public class Memoservlet extends HttpServlet {

private static final long serialVersionUID = 1L;

servlet 소스

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

    

doProcess(request, response);

}

    protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

    

doProcess(request, response);

}

private void doProcess(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

    //1.한글처리

     request.setCharacterEncoding("UTF-8");

     response.setContentType("text/html;charset=UTF-8");

    

    //2.데이터 받기

     String id = request.getParameter("id");

     String email = request.getParameter("email");

     String memo = request.getParameter("memo");

        

    //3.DB연결

    //4.Insert 실행

     memodao dao = new memodao();

     int n = dao.insertMemo(id, email, memo);

    

    //5.응답구성

     PrintWriter out = response.getWriter();

    

     if(n>0) {

  out.print("<script>");

  out.print("alert('성공적으로 회원가입이 완료되었습니다');");

  out.print("location.href = 'http://localhost:8090/WebServlet_4_memo_mvc/memo.html'");

  out.print("</script>");

   

  }else {

         // int resultrow = 0

         // 여기서 else문이 발동된다는 것은 dao 단에서 exception이 발생했다는 의미이다

        

         out.print("<script>");

         out.print("alert('회원 가입에 실패하였습니다');");

         out.print("</script>");

     }

}

<연산을 통해 객체를 받을 때> -> RequestDispatcher

예제 1)

<c:set var="memolist" value="${requestScope.memolist}"></c:set>

<div align=center>

<hr color=green width=400><h2> Line Memo List </h2><hr color=green width=400>

<table>

     <tr>

        <th>Writer</th>

        <th>MemoContent</th>

        <th>Email</th>

     </tr>

     <c:forEach var="memo" items="${memolist}">

        <tr>

            <td>${memo.id}</td> <-- ~.으로 접근하려면 getter구현 선행이 필수!!

            <td>${memo.email}</td>

            <td>${memo.content}</td>

        </tr>

     </c:forEach>

</table>

</div>

<a href='memo.html'>글쓰기</a>

</body>

</html>

EL에서 ~.으로 접근하려면 getter구현 선행이 필수!!

protected void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

    doProcess(request, response);

}

protected void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

    doProcess(request, response);

}

private void doProcess(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

      

     // View page 별도 사용 : memolist.jsp

     try {

             // 전체 데이터 조회

             memodao dao = new memodao();

             ArrayList<memo> memolist = dao.getMemoList();

            

             // 요청 결과 저장

             request.setAttribute("memolist", memolist);

        

             // View 페이지 설정

             RequestDispatcher dis = request.getRequestDispatcher("/memolist.jsp");

            

             // request와 response가 가진 주소를 포워드

             dis.forward(request, response);

            

        

     }catch (Exception e) {

         e.printStackTrace();

     }

    

     }

}

예제 2)

public class Empdao {

    Connection cn = null;

    ResultSet rs = null;

    

    public Empdao() {

        cn = Singleton_Helper.getConnection("oracle");

    }

    

    public Emp emp_search(int empno){

        Emp temp = new Emp();

        String sql = "select * from emp where id = " + "'" + empno + "'";

                

        try {

            Statement stmt = cn.createStatement();

            rs = stmt.executeQuery(sql);

            

            while(rs.next()) {

                temp = new Emp(

                        rs.getInt(1),

                        rs.getString(2),

                        rs.getString(3),

                        rs.getInt(4),

                        rs.getString(5),

                        rs.getInt(6),

                        rs.getInt(7),

                        rs.getInt(8)

                        );

                return temp;

            }

            

        } catch (SQLException e) {

            e.printStackTrace();

        

        } finally {

            Singleton_Helper.close(rs);

            Singleton_Helper.close(cn);

        }

        return temp;

    }

}

private void doProcess(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

        

    request.setCharacterEncoding("UTF-8");

    response.setContentType("text/html;charset=UTF-8");

    int empno = Integer.parseInt(request.getParameter("empno"));

    

    Empdao dao = new Empdao();

    Emp emp = dao.emp_search(empno);

    

    RequestDispatcher dis = request.getRequestDispatcher("/memolist.jsp");

        

    dis.forward(request, response);

}   

}