📄 ch13.txt

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/* 代码13-1
 * Created on 2005-5-22
 */

//:! c15:jsp:ShowSeconds.jsp
<html><body>
<H1>The time in seconds is: 
<%= System.currentTimeMillis()/1000 %></H1>
</body></html>
///:~

/* 代码13-2
 * Created on 2005-5-22
 */

//Hello.jsp
<%-- This JSP comment will not appear in the
generated html --%>
<%-- This is a JSP directive: --%>
<%@ page import="java.util.*" %>
<%-- These are declarations: --%>
<%!
    long loadTime= System.currentTimeMillis();
    Date loadDate = new Date();
    int hitCount = 0;
%>
<html><body>
<%-- The next several lines are the result of a 
JSP expression inserted in the generated html;
the '=' indicates a JSP expression --%>
<H1>This page was loaded at <%= loadDate %> </H1>
<H1>Hello, world! It's <%= new Date() %></H1>
<H2>Here's an object: <%= new Object() %></H2>
<H2>This page has been up 
<%= (System.currentTimeMillis()-loadTime)/1000 %>
seconds</H2>
<H3>Page has been accessed <%= ++hitCount %> 
times since <%= loadDate %></H3>
<%-- A "scriptlet" that writes to the server
console and to the client page. 
Note that the ';' is required: --%>
<%
   System.out.println("Goodbye");
   out.println("Cheerio");
%>
</body></html>
///:~

/* 代码13-3
 * Created on 2005-5-22
 */

//DisplayFormData.jsp
<%-- Fetching the data from an HTML form. --%>
<%-- This JSP also generates the form. --%>
<%@ page import="java.util.*" %>
<html><body>
<H1>DisplayFormData</H1><H3>
<%
  Enumeration flds = request.getParameterNames();
  if(!flds.hasMoreElements()) { // No fields %>
    <form method="POST" 
    action="DisplayFormData.jsp">
<%  for(int i = 0; i < 10; i++) {  %>
      Field<%=i%>: <input type="text" size="20"
      name="Field<%=i%>" value="Value<%=i%>"><br>
<%  } %>
    <INPUT TYPE=submit name=submit 
    value="Submit"></form>
<%} else { 
    while(flds.hasMoreElements()) {
      String field = (String)flds.nextElement();
      String value = request.getParameter(field);
%>
      <li><%= field %> = <%= value %></li>
<%  }
  } %>
</H3></body></html>
///:~

/* 代码13-4
 * Created on 2005-5-22
 */

//PageContext.jsp
<%--Viewing the attributes in the pageContext--%>
<%-- Note that you can include any amount of code
inside the scriptlet tags --%>
<%@ page import="java.util.*" %>
<html><body>
Servlet Name: <%= config.getServletName() %><br>
Servlet container supports servlet version:
<% out.print(application.getMajorVersion() + "."
+ application.getMinorVersion()); %><br>
<%
  session.setAttribute("My dog", "Ralph");
  for(int scope = 1; scope <= 4; scope++) {  %>
    <H3>Scope: <%= scope %> </H3>
<%  Enumeration e =
      pageContext.getAttributeNamesInScope(scope);
    while(e.hasMoreElements()) {
      out.println("\t<li>" + 
        e.nextElement() + "</li>");
    }
  }
%>
</body></html>
///:~

/* 代码13-5
 * Created on 2005-5-22
 */

//SessionObject.jsp
<%--Getting and setting session object values--%>
<html><body>
<H1>Session id: <%= session.getId() %></H1>
<H3><li>This session was created at 
<%= session.getCreationTime() %></li></H1>
<H3><li>Old MaxInactiveInterval = 
  <%= session.getMaxInactiveInterval() %></li>
<% session.setMaxInactiveInterval(5); %>
<li>New MaxInactiveInterval= 
  <%= session.getMaxInactiveInterval() %></li>
</H3>
<H2>If the session object "My dog" is 
still around, this value will be non-null:<H2>
<H3><li>Session value for "My dog" =  
<%= session.getAttribute("My dog") %></li></H3>
<%-- Now add the session object "My dog" --%>
<% session.setAttribute("My dog", 
                    new String("Ralph")); %>
<H1>My dog's name is 
<%= session.getAttribute("My dog") %></H1>
<%-- See if "My dog" wanders to another form --%>
<FORM TYPE=POST ACTION=SessionObject2.jsp>
<INPUT TYPE=submit name=submit 
Value="Invalidate"></FORM>
<FORM TYPE=POST ACTION=SessionObject3.jsp>
<INPUT TYPE=submit name=submit 
Value="Keep Around"></FORM>
</body></html>
///:~

/* 代码13-6
 * Created on 2005-5-22
 */

//jsp:Cookies.jsp
<%--This program has different behaviors under
 different browsers! --%>
<html><body>
<H1>Session id: <%= session.getId() %></H1>
<%
Cookie[] cookies = request.getCookies();
for(int i = 0; i < cookies.length; i++) { %>
  Cookie name: <%= cookies[i].getName() %> <br>
  value: <%= cookies[i].getValue() %><br>
  Old max age in seconds: 
  <%= cookies[i].getMaxAge() %><br>
  <% cookies[i].setMaxAge(5); %>
  New max age in seconds: 
  <%= cookies[i].getMaxAge() %><br>
<% } %>
<%! int count = 0; int dcount = 0; %>
<% response.addCookie(new Cookie(
    "Bob" + count++, "Dog" + dcount++)); %>
</body></html>
///:~

/* 代码13-7
 * Created on 2005-5-22
 */
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