Servlet & JSP day13 - 표준 액션 태그(jsp:useBean)

 

<jsp:useBean>

☞ 속성 영역(page, request, session, application)에 binding된 속성 객체를 lookup한다. 만약 가져오지 못하면 생성하여 그 영역에 binding 한다.

☞ 태그의 attribute(속성)

◎ id : 자바식별자, binding 시 설정 이름

◎ class : lookup할 클래스 이름. fully name으로 설정

◎ scope : 속성 영역, 값 : page(기본), request, session, application

◎ 예)

<jsp:useBean id="mto" class="dto.MemberDTO" scope="request" />

-> 의미

MemberDTO mto = (MemberDTO)request.getAttribute("mto");

if(mto==null) {

mto = new MemberDTO();

request.setAttribute("mto", mto);

}

 

RegisterServlet.java

☞ package : myjsp.actiontag

☞  req.jsp를 통해 입력받은 정보를 CutomerDTO객체에 저장하고 그 저장한 객체를 binding하여 요청 디스패치방식으로 res1.jsp와 res2.jsp로 전송한다.

소스보기

package myjsp.actiontag;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import myjsp.dto.CustomerDTO;

public class RegisterServlet extends HttpServlet {
 private static final long serialVersionUID = 1L;

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

 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  
  request.setCharacterEncoding("utf-8");
  //1. 요청 파라미터 조회
  String id = request.getParameter("id");
  String password = request.getParameter("password");
  String name = request.getParameter("name");
  String email = request.getParameter("email");
  int age = -1;
  try {
   age= Integer.parseInt(request.getParameter("age"));
  } catch(NumberFormatException e) {
   e.printStackTrace();
  }
  
  //2. CustomerDTO 객체 생성 <- 요청 파라미터 값을 설정
  CustomerDTO cto = new CustomerDTO(id, password, name, email, age);

 

  //3. request scope에 2번의 객체를 binding
  request.setAttribute("cto", cto);
  
  HttpSession session = request.getSession();
  session.setAttribute("session_cto", cto);
  
  //4. /actiontag/res1.jsp로 요청 디스패치 방식으로 이동
  RequestDispatcher rdp = request.getRequestDispatcher("/actiontag/res1.jsp");
  rdp.forward(request, response);
 }

}

 

CustomerDTO.java

☞ package : myjsp.dto

☞ id, password, name, email, age에 관한 생성자, setter/getter메소드, toString()메소드, hashCode() 메소드 

소스보기 

package myjsp.dto;

public class CustomerDTO {
 private String id;
 private String password;
 private String name;
 private String email;
 private int age;
 public CustomerDTO() { }
 public CustomerDTO(String id, String password, String name, String email,
   int age) {
  super();
  this.id = id;
  this.password = password;
  this.name = name;
  this.email = email;
  this.age = age;
 }
 public String getId() {
  return id;
 }
 public void setId(String id) {
  this.id = id;
 }
 public String getPassword() {
  return password;
 }
 public void setPassword(String password) {
  this.password = password;
 }
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
 public String getEmail() {
  return email;
 }
 public void setEmail(String email) {
  this.email = email;
 }
 public int getAge() {
  return age;
 }
 public void setAge(int age) {
  this.age = age;
 }
 @Override
 public String toString() {
  return "CustomerDTO [id=" + id + ", password=" + password + ", name="
    + name + ", email=" + email + ", age=" + age + "]";
 }
 @Override
 public int hashCode() {
  final int prime = 31;
  int result = 1;
  result = prime * result + age;
  result = prime * result + ((email == null) ? 0 : email.hashCode());
  result = prime * result + ((id == null) ? 0 : id.hashCode());
  result = prime * result + ((name == null) ? 0 : name.hashCode());
  result = prime * result
    + ((password == null) ? 0 : password.hashCode());
  return result;
 }
 @Override
 public boolean equals(Object obj) {
  if (this == obj)
   return true;
  if (obj == null)
   return false;
  if (getClass() != obj.getClass())
   return false;
  CustomerDTO other = (CustomerDTO) obj;
  if (age != other.age)
   return false;
  if (email == null) {
   if (other.email != null)
    return false;
  } else if (!email.equals(other.email))
   return false;
  if (id == null) {
   if (other.id != null)
    return false;
  } else if (!id.equals(other.id))
   return false;
  if (name == null) {
   if (other.name != null)
    return false;
  } else if (!name.equals(other.name))
   return false;
  if (password == null) {
   if (other.password != null)
    return false;
  } else if (!password.equals(other.password))
   return false;
  return true;
 }
 
 
}

 

req.jsp

☞ folder : WebContent/actiontag 

소스보기

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
고객 정보 등록<br>
<form action="/myjsp/register" method="post">
 ID : <input type="text" name="id"><br>
 Password : <input type="password" name="password"><br>
 이름 : <input type="text" name="name"><br>
 나이 : <input type="text" name="age"><br>
 이메일 : <input type="text" name="email"><br>
 <input type="submit" value="등록">
</form>
</body>
</html>

 

res1.jsp

☞ foder : WebContent/actiontag

☞ jsp:useBean 을 사용하여 request scope에 공유된 CustomerDTO 객체를 출력

소스보기

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%--
<%
 CustomerDTO mcto = (CustomerDTO)request.getAttribute("cto");
 if(mcto==null) {
  mcto = new CustomerDTO();
  request.setAttribute("mcto", mcto);
 }
%>
 --%>
<jsp:useBean id="cto" class="myjsp.dto.CustomerDTO" scope="request"/>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
ID : <%= cto.getId() %><br>
Password : <%= cto.getPassword() %><br>
이름 : <%= cto.getName() %><br>
나이 : <%= cto.getAge() %><br>
이메일 : <%= cto.getEmail() %>
<p>
<a href="/myjsp/actiontag/res2.jsp">res2.jsp</a>
</p>

</body>
</html>

 

res2.jsp

☞ folder : WebContent/actiontag

☞ jsp:useBean 을 사용하여 session scope에 공유된 CustomerDTO 객체를 출력

소스보기

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<jsp:useBean id="session_cto" class="myjsp.dto.CustomerDTO" scope="session" />
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
Session Scope 결과<br>
ID : <%= session_cto.getId() %><br>
Password : <%= session_cto.getPassword() %><br>
이름 : <%= session_cto.getName() %><br>
나이 : <%= session_cto.getAge() %><br>
이메일 : <%= session_cto.getEmail() %><br>
</body>
</html>