노력과 삽질 퇴적물
JSP: 표현언어(el) 본문
0. 기본개념
JSP 2.0부터 지원
JSP페이지에서 자바코드를 없애기 위한 방법
값이 없으면 null을 출력X, 기본적으로 자바문법 사용
*.jsp문서에서 정삭적으로 작동한다.
1. EL 변수 출력법
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>el01.jsp</title> </head> <body> <h3> 간단한 표현 언어(EL) 예제입니다.</h3> <table border="1"> <tr> <th>표현값</th> <th>값</th> </tr>
<tr> <td>사칙연산</td> <td>${2+5}, ${2-5}, ${2*5}, ${2/5}</td> </tr>
<tr> <td>나머지</td> <td>${5 mod 7}</td> </tr>
<tr> <td>보다작다</td> <td>${2<3}</td> </tr>
<tr> <td>크다, 작다</td> <td>${2 gt 3}, ${2 lt 3}</td> </tr>
<tr> <td>크거나 같다, 작거나 같다</td> <td>${3.1 ge 3.2}, ${3.1 le 3.2}</td> </tr>
<tr> <td>브라켓 연산자 [ip와 port번호]</td> <td>${header["host"]}, ${header['host']}, ${header.host} </td> </tr>
<tr> <td>브라켓 연산자[웹 브라우저 종류]</td> <td>${header["user-agent"]}, ${header['user-agent']}, ${header.user-agent}</td> </tr> </table> </body> </html> |
2. 파리미터 전달과 처리
el02_form.jsp |
<%@ 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>el02_form.jsp</title> </head> <body> <h3>표현언어의 파라미터 값 처리</h3> <form action="el02_View.jsp" method="post"> 이름 : <input type="text" name="name"/><br><br> 선택 : <input type="checkbox" name="lang" value="JAVA"/>JAVA<br> 선택 : <input type="checkbox" name="lang" value="JSP"/>JSP<br> 선택 : <input type="checkbox" name="lang" value="오라클"/>오라클<br> 선택 : <input type="checkbox" name="lang" value="C++"/>C++<br> <input type="submit" value="OK"/> <input type="reset" value="cancel"/> </form> </body> </html> |
el02_View.jsp |
<%@ 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"> <% request.setCharacterEncoding("utf-8"); %> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>el02_View.jsp</title> </head> <body> 이름은 ${param.name}입니다.<br> 과일은 ${paramValues.lang[0]} ${paramValues.lang[1]} ${paramValues.lang[2]} ${paramValues.lang[3]}입니다. </body> </html> |
3. 표현언어에서 매소드
el03_form.jsp | <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib prefix="el" uri="/WEB-INF/tlds/el-functions.tld" %> <!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>el03_form.jsp</title> </head> <body> <h3>표현언어에서 매소드 사용하기</h3> <form action="el03_View.jsp" method="post"> x : <input type="text" name ="x"><br><br> y : <input type="text" name ="y"><br><br> <input type="submit" value="덧셈연산"> </form> </body> </html> |
| el03_View.jsp | <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib prefix="el" uri="/WEB-INF/tlds/el-functions.tld" %> <!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>el03_View.jsp</title> </head> <body> ${param.x }, ${param.y }입니다. 합 ${el:add( param.x, param.y )}입니다. </body> </html> |
el03-2.jsp | <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib prefix="el" uri="/WEB-INF/tlds/el-functions.tld" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <% java.util.Date today = new java.util.Date(); request.setAttribute("today", today); %> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>el03-2.jsp</title> </head> <body> 오늘은 ${el:getFormat(today) } </body> </html> |
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