Apache Struts Framework

8/2/2019 Apache Struts Framework

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Copyright 2006 Celeritas Technologies, LLC

StrutsWhat they are, and How we use em

PEG Lunch-n-LearnNov 9, 2005


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Struts are support mechanisms


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What is Struts?

MVC-based (Model-View-Controller)open source software

Hosted by Apache Software Foundation

Used to support the building of businessapplications


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The Big Picture

Struts-config.xml - provides configurationinformation to the Action Servlet for all Struts objectsthat will be used by the application.

Action Servlet - controls navigational flow. Action Class - accesses the business classes.

Action Form - validates form inputs; provides accessfor the action class to the request parameters; usedby action class to store and retrieve data.

ActionForward - forwards the request to thespecified path.


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The Big Picture

Struts-config.xml

Action

Servlet

Action

Form

JSP

JSP

submit

respond

start up


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Application Set-up

Jar files Tag libraries

Struts-config dtdApplication.properties

Apache vhost file

Web.xml

Struts-config.xml


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Application Set-up (cont.)

Jar files Place in \WEB-INF\lib

Tag Libraries

Place in \WEB-INF\taglibs

Struts-config dtd

Place in \WEB-INF


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Application.properties Default location: \WEB-INF\classes\resources

Somewhat configurable

Name can be name.properties

Location can be \WEB-INF\classes\folder name

Currently using bundles folder name

Contains messages for display within theapplication


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Apache vhost file:RewriteRule ^/TicketManagement/?$ /TicketManagement/soComLogin.jsp [R]

DirectoryIndex soComLogin.jspOrder deny,allow

Allow from all

### These JkMount directives will determine what requests will be sent### to Tomcat.JkMount / TicketManagement/ * .do aj p13

JkMount /TicketManagement/*.jsp ajp13


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Web.xml fileAction servlet configuration

Servlet request mapping

Struts tag libraries configuration


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Web.xml Set-up

Servlet configuration:

actionorg.apache.struts.action.ActionServlet

config/WEB-INF/conf/struts-config.xml

debug2

detail2

2


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Web.xml Set-up (cont.)

Servlet request mapping:

action*.do


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Web.xml Set-up (cont.)

Struts tag libraries configuration:

/taglibs/struts-beantaglibs/struts-bean.tld

/taglibs/struts-htmltaglibs/struts-html.tld

/taglibs/struts-logictaglibs/struts-logic.tld

/taglibs/struts-nestedtaglibs/struts-nested.tld


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Struts-config.xml Location: \WEB-INF\conf

Basic configuration tags


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Struts-config.xml

Global-exceptionsAllows exceptions to be handled in a

consistent way by all Action objects.

Define exception handler to handleexceptions thrown by an Action object.

Format:


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Struts-config.xml (cont.)

Form-beans Defines what ActionForm objects can be

created by the ActionServlet, and what to

call them. Format:


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Global-forwards Defines ActionForward paths that are

available to all Actions in an application.

Format:


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Action-mappings Define what operations the application can

undertake.


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Message-resources Deploys the message bundle files needed

by the application (xyz.properties).

Default file: \WEB-INF\classes\resources\application.properties

Format:


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Plug-in Defines special resources that are available

to the Action classes.

Format:


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Simple Example Request

Request is sent to the ActionServlet/Request.do?param1=value&param2=

Servlet checks the ActionMapping forRequest.do

Servlet instantiates the ActionForm

Form is populated with request parametersvia setter methods, i.e. setParam1(String pValue)

Form performs any validation on the

supplied values


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Simple Example Request (cont.)

Servlet executes the specified Actionclass, passing it the ActionForm

Action class does its duty, gettingand/or setting data in the ActionForm

Action forwards to the ActionServlet

Servlet executes a JSP JSP displays data from the ActionForm


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A Brief Look at

Struts HTML Tags

A wide range of tags are available Complete list and description found at:

http://struts.apache.org/struts-taglib/index.html orhttp://struts.apache.org/struts-doc-1.2.7/userGuide/index.html

Use can replace Java code in a JSP

Can be somewhat clunky to use

Not always applicable to coding needs


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A Brief Look at

Struts HTML Tags (cont.)

Example of form and message tags

. . .


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A Brief Look at


Example of submit and button tags


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A Brief Look at


Example of logic and select-box tags

Ticket History:


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Thread Safety

Servlet creates one instance of eachAction class per application.

Only use local variables, not instance

(class) variables.

Shared values must be passed through

the method signatures.


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Modular Applications

Multiple modules can run within thesame application space

Each module has its own prefix

Prefix corresponds to the folder namewhere the module files reside

Module configuration is in web.xml


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Modular Applications (cont.)

Web.xml setup

config/WEB-INF/conf/struts-config.xml

config/adminModule/WEB-INF/conf/struts-adminModule.xml

config/loginModule/WEB-INF/conf/struts-loginModule.xml


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Struts-loginModule.xml setup


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Modules are referenced bymoduleName/action

Example of vhost file:

### do a redirect to the entry point for this applicationRewriteEngine OnRewriteRule /TicketManagement/?$ /TicketManagement/loginModule/Login.do [R]### RewriteRule ^/TicketManagement/?$ /TicketManagement/soComLogin.jsp [R]


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Pros Modules can be developed/modified

independently

Smaller, cleaner configuration files

Cons

Global items (forwards, exception handlers,plug-ins) must be defined in each modulethat needs access to them


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Possible work-around #1config

/WEB-INF/conf/struts-config-common.xml,/WEB-INF/conf/struts-config.xml

config/module2

/WEB-INF/conf/struts-config-common.xml,/WEB-INF/conf/struts-config-module2.xml


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Possible work-around #2config

/WEB-INF/conf/struts-config.xml,/WEB-INF/conf/struts-config-module1.xml,

/WEB-INF/conf/struts-config-module2.xml


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Struts Tiles


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What is Struts Tiles

Tiles is a templating libraryAllows construction of pages in

interchangeable parts (tiles)

Facilitates the creation of reusableview components


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Page Construction

A page can bebroken into sectionswhich are

implemented as tiles Each tile may have

its own Action and

Form class or maytake part in others


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A WebFast Example

Webfast UserRegistration, UserAdministration and

SecurityAdministration alluse tiles (in variouscombinations)


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Adding Tiles to thestruts-config.xml


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The Tile Configuration


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Grouting the Tiles


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Celeritas Technologies

www.celeritas.com

http://java.celeritas.com7101 College Blvd, Sixth FloorOverland Park, KS 66210

913.491.9000

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