선언문,request객체의메서드들,화면이동하기

[ex] 
a.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>

<%%>
<a href="c/b.jsp?a=1&b=2&c=3">문서</a>

[an1]
ap1/c/b.jsp
===========
<%@ page contentType="text/html;charset=euc-kr" %>
<%
 String s1=request.getParameter("a");
 String s2=request.getParameter("b");
 String s3=request.getParameter("c");

 out.println(s1+"<br>");
 out.println(s2+"<br>");
 out.println(s3+"<br>");
%>

[an2]
ap1/c/b.jsp
===========
<%@ page contentType="text/html;charset=euc-kr" %>
<%=request.getParameter("a")%><br>
<%=request.getParameter("b")%><br>
<%=request.getParameter("c")%><br>

 

====================================================================================================

[ex] 실행해보기
a.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<form action="b.jsp">
 <input type="text" name="t1">
 <input type="submit">
</form>

b.jsp
======
<%@ page contentType="text/html;charset=euc-kr" %>
<%=request.getParameter("t1")%>

====================================================================================================

 

[ex] 전송버튼을 클릭하면 체크박스에 선택된 값이 
 화면에 출력될 수 있도록 소스코드를 작성하시오.
a.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<form action="b.jsp">  
 <input type="checkbox" name="ch" value="javascript">javascrip

 <input type="checkbox" name="ch" value="java">java
 <input type="checkbox" name="ch" value="oracle">oracle
 <input type="checkbox" name="ch" value="xml">xml
 <input type="checkbox" name="ch" value="jquery">jquery
 <input type="submit">
</form>

[an]
b.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<%
 for(String s: request.getParameterValues("ch")){
  out.println(s+"<br>");
 }
%>

http://localhost:8090/ap2/a.jsp?a=1&b=2&c=3

출력 b a c            <----정렬되지 않고 출력된다.~

====================================================================================================

getParameterNames() 활용

<%@ page contentType="text/html;charset=euc-kr" %>

<%@ page import="java.util.*"%>

<%

Enumeration<String> e = request.getParameterNames();

while(e.hasMoreElements())

out.println(e.nextElement());

%>

 

[ex] a.jsp를 아래와 같이 실행한뒤

 http://localhost:8282/ap1/a.jsp?a=11&b=66

 '문서'를 클릭했을때 위url에서 입력했던 파라미터의값을 
 출력되게하려면 아래소스코드를 어떻게 수정해야할까?

 11
 66

a.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<a href="b.jsp">문서</a>

b.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<%=request.getParameter("a")%><br>
<%=request.getParameter("b")%><br>

[an]

a.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<% 
 String s1=request.getParameter("a");
 String s2=request.getParameter("b");
%>
<a href="b.jsp?aa=<%=s2%>&bb=<%=s2%>">문서</a>

b.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<%=request.getParameter("aa")%><br>
<%=request.getParameter("bb")%><br>

====================================================================================================

[ex]

ap1/WEB-INF/src/Member.java
ap1/WEB-INF/classes
ap1/a.jsp

 

package a.b;
public class Member{
 private String id;
 public void setId(String id){
  this.id=id;
 }
 public String getId(){
  return id;
 }
}

 

ap1/WEB-INF/classes> javac  -d  .  ../src/Member.java

a.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<%@ page import="a.b.Member" %>
<%
 Member m=new Member();
 out.println(m);
%>

 

====================================================================================================

[ex]

a.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<%@ page import="java.io.*" %>        //import하는 부분이다 잘 기억하도록
<%!
 void a(JspWriter out) throws IOException{
  out.println("aaa");
 }
%>
<%
 a(out);
%>

 

====================================================================================================

[ex]
 http://localhost:8282/ap1/a.jsp

 문서

a.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<a href="<%=request.getContextPath()%>/b.jsp">문서</a> //getContextPath는 경로지정

 

http://localhost:8282/b.jsp

 404

==================================================================================================== 

[ex]

http://localhost:8282/ap1/a.jsp?a=11&a=22&b=33&c=44

 

<%@ page contentType="text/html;charset=euc-kr" %>
<%@ page import="java.util.*" %>
<%
 Map<String,String[]> map=request.getParameterMap(); // map은 sort되지 않는다.
 Set<String> set=map.keySet();
 for(String key:set){
  out.println(key+"<br>");
 }
%>

 

keySet()     : 선택한 키값을 리턴

entrySet()   :이 키와 값을 모두리턴

====================================================================================================

[ex] 아래와 같이 실행될 수 있도록 소스코드를 작성하시오.

 http://localhost:8282/ap1/a.jsp?a=11&a=22&b=33&c=44

 a : 11, 22
 b : 33
 c : 44

[an]
<%@ page contentType="text/html;charset=euc-kr" %>
<%@ page import="java.util.*" %>
<%
 Map<String,String[]> map=request.getParameterMap();

 for(String key: map.keySet()){
  out.println(key + ":");
  for(String v: map.get(key)){
   out.println(v+",");
  }
  out.println("<br>");
 }
%>

[참고]

request.getParameterMap()는 request 에 담긴 parameter만 빼내서 Map으로 저장해주는 메서드이다. 

====================================================================================================

# method방식 : get, post

[ex]
a.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<form action="b.jsp" method="post">  // get은 한글이 깨지고 post는 한글 안깨짐.
 <input type="text" name="t">
 <input type="submit">
</form>

b.jsp

=====

<%@ page contentType="text/html;charset=euc-kr" %>

<% request.setCharacterEncoding("euc-kr");%> // 한글이 안깨지게 해주는 로직

<%=request.getParameter("t")%>

 

# 화면이동하는 세가지 방식  

1. response.sendRedirect("xxx.jsp");

2.     <script>
             location.href="xxx.jsp";
      </script> 

3. <jsp:forward page="xxx.jsp" />

     : 현재 request 주소와 다음 request 주소가 같다! 유일하게

====================================================================================================

[ex] 
a.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<form action="b.jsp">    
 <input type="text" name="id"><br>
 <input type="text" name="pw"><br>
 <input type="text" name="addr"><br>
 <input type="text" name="tel"><br>
 <input type="submit">
</form>

b.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<jsp:forward page="c.jsp" />

 

c.jsp
=====
<%@ page contentType="text/html;charset=euc-kr" %>
<%=request.getParameter("id")%><br>
<%=request.getParameter("pw")%><br>
<%=request.getParameter("addr")%><br>
<%=request.getParameter("tel")%><br>