pdf / 5-jsp+jstl

JSP

Java Server Pages

JSP концепция

Template Data

Addition of Dynamic Data

Encapsulation of Functionality

JavaBeans

Tag libraries

Good Tool Support

Основные понятия

JSP pages and servlet classes - web components

JSP pages are textual components

Translation phase

Request phase

Deployment Descriptor

<jsp-config>

<taglib>

<jsp-property-group>

JSP

JSP

JSP page или JSP document (XML well-formed)

JSP translation - validating JSP pages

Events in JSP Pages

jspInit()

jspDestroy()

Compiling JSP Pages

Deployment time

Development time

JSP состоит из

Элементов

Template data

Element Syntax

Directives

Обеспечивают информацию для фазы трансляции

<%@ directive...%>

Actions

Фаза обработки запроса

standard

custom

<mytag attr1=”attribute value” ...></mytag>

Scripting Elements

<mytag attr1=”${bean.property}”.../> ${map[entry]} <lib:myAction>${3+counter}</lib:myAction> Старые scripting elements:

Declarations <%! ... %>

Scriptlets <% ... %>

Expressions <%= ... %>

Error Handling

Translation Time Processing Errors HTTP 500

Request Time Processing Errors

errorPage URL

ServletRequest attributes

javax.servlet.error.status_code (Integer)

javax.servlet.error.exception_type (Class)

javax.servlet.error.message (String)

javax.servlet.error.exception (Throwable)

javax.servlet.error.request_uri (String)

javax.servlet.error.servlet_name (String)

Using JSPs as Error Pages

page directive’s isErrorPage attribute to true

exception implicit scripting language variable

ErrorData ${pageContext.errorData.statusCode}

JSP page class

_jspService() method

JspWriter (out)

Нельзя из текста jsp напрямую работать с PrintWriter or OutputStream

Неявные объекты

request - subtype of javax.servlet.ServletRequest

response - subtype of javax.servlet.ServletResponse

pageContext - javax.servlet.jsp.PageContext

session - javax.servlet.http.HttpSession

application - javax.servlet.ServletContext

out - javax.servlet.jsp.JspWriter

config - javax.servlet.ServletConfig

page - java.lang.Object

exception - java.lang.Throwable (для error pages)

The page Directive

<%@ page page_directive_attr_list %>

Language

extends

import

session

buffer

autoFlush

isThreadSafe

info

errorPage

isErrorPage

contentType

pageEncoding

isELIgnored