SCWCD Notes

response.getPrintWriter() & getOutputStream() can not be called on same instance twice, otherwise throw IllegalStateException

sendRedirect() 
can not be called if response is commited/flushed, otherwise exception will be thrown
tell browser to get resource from another location

ServeletContext -> getResource() & getResourceAsStream() 

• Can NOT access dynamic resource such as JSP, Servlet
• Might cause security issue if not used properly

ServletContext -> getRealPath() is NOT FOR

• file sitting in Jar file
• file sitting in network

JSP:useBean

1. id - compulsory
2. scope - optional
3. combine of following

• class
• type
• class & type
• beanName & type

<jsp:setProperty name="beanName" property="property"|param="property" />
* param is parameter from request

<jsp:setProperty/getProperty name="..." property="..." /> will do automatic conversion

JSP container populate tablib mapping in Three ways

1. container explicit-map definition in web.xml
2. container Implicit-map the one defined in packed Jar file (tld file contains URI info),
3. container add known entries by default, such as http://java.sun.com/JSP/jstl/a.tld

taglib lookUp

• roote-relative URL
• relative URL, container will append "WEB-INF" in front of the relative URL

IF NOT FOUND

• If absolute URI, error thrown
• If root-relative, try to find on application's root directory
• if relative-path, try to find it on the same location as JSP

Three different ways to get RequestDispatcher in servlet

• getServletContext().getRequestDispatcher("/user/absolute/path/servlet")
• ServletContext.getNamedDispatcher("nameOfServletInWebXML")
• request.getRequestDispatcher("maybe/relative")

 

Forward

• <jsp:forward .../>, RequestDispatcher.forward() are refered as "Server-side"

Redirect

• Client side redirect

 

Authenticate

• Basic - not encrypted, password saved in plain text
  
• Digest - encrypted
• Client-Cert - end user authenticate using HTTPS, require user to possess public key certificate (PKC)

• Form - form method: POST, action: j_security_check, username field: j_username, password filed: j_password