Stripes Java

Java Web Development with Stripes

Samuel Santos

About me

• Senior Java Engineer and Web Advocate at Present Technologies

• Open source enthusiast

• Web standards contributor

• Casual blogger

Present Technologies 2

Agenda

• Why

• What is it

• Goals

• Setting up

• Features

• Extensions

• Find more

• Q&APresent Technologies 3

Why

“Java web development doesn’t have to suck.”Tim Fennell, Stripes author


Why

“Have you ever used a framework and felt you had to do too much work for the framework compared to what the framework gave you in return?”

Freddy Daoud, Stripes Book


What is it

• Stripes is a Model-View-Controller (MVC) framework

• Stripes is not a “full-stack” framework

• Stripes is an action-based framework


Goals

• Make developing web applications in Java easy

• Provide simple yet powerful solutions to common problems

• Make the Stripes ramp up time for a new developer less than 30 minutes

• Make it really easy to extend Stripes, without making you configure every last thing

From Stripes Homepage


Setting up


<filter> <filter-name>StripesFilter</filter-name> <filter-class>net.sourceforge.stripes.controller.StripesFilter</filter-class> <init-param> <param-name>ActionResolver.Packages</param-name> <param-value>com.example.javapt09.stripes.action</param-value> </init-param> </filter> <servlet> <servlet-name>DispatcherServlet</servlet-name> <servlet-class>net.sourceforge.stripes.controller.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <filter-mapping> <filter-name>StripesFilter</filter-name> <servlet-name>DispatcherServlet</servlet-name> <dispatcher>REQUEST</dispatcher> <dispatcher>FORWARD</dispatcher> <dispatcher>ERROR</dispatcher> </filter-mapping> <servlet-mapping> <servlet-name>DispatcherServlet</servlet-name> <url-pattern>*.action</url-pattern> </servlet-mapping>

Features - Smart binding

URLs binding


public class SmartBindingActionBean extends BaseActionBean { ... }

<s:link beanclass="com.example.javapt09.stripes.action.SmartBindingActionBean">Smart binding</s:link> <s:link href="${contextPath}/SmartBinding.action">Smart binding</s:link>

Parameters

And Events

<s:form beanclass="com.example.javapt09.stripes.action.SmartBindingActionBean"> <p> <s:label for="user.firstName" /> <s:text id="user.firstName" name="user.firstName" /> </p> <p> <s:label for="user.lastName" /> <s:text id="user.lastName" name="user.lastName" /> </p> <p> <s:submit name="print" /> </p> </s:form>

public class SmartBindingActionBean extends BaseActionBean { @ValidateNestedProperties({ @Validate(field = "firstName", required = true, maxlength = 100), @Validate(field = "lastName", required = true, maxlength = 100) }) private User user; public User getUser() { return user; } public void setUser(User user) { this.user = user; } @DefaultHandler @DontValidate public Resolution main() { return new ForwardResolution("/WEB-INF/jsp/binding-validation.jsp"); } public Resolution print() { getContext().getMessages().add(new LocalizableMessage( "com.example.javapt09.stripes.action.SmartBindingActionBean.print.success", user)); return new RedirectResolution(SmartBindingActionBean.class); } }




Localized buttons and labels


<s:form beanclass="com.example.javapt09.stripes.action.SmartBindingActionBean"> <p> <s:label for="user.firstName" /> <s:text id="user.firstName" name="user.firstName" /> </p> <p> <s:label for="user.lastName" /> <s:text id="user.lastName" name="user.lastName" /> </p> <p> <s:submit name="print" /> </p> </s:form>

com.example.javapt09.stripes.action.SmartBindingActionBean.user.firstName=First name com.example.javapt09.stripes.action.SmartBindingActionBean.user.lastName=Last name com.example.javapt09.stripes.action.SmartBindingActionBean.print=Print

Features - Validation

Frequently used @Validate attributes


Attribute Type Description

field String Name of nested field to validate.

required boolean true indicates a required field.

on String[] Event handlers for which to apply.

minlength int Minimum length of input.

maxlength int Maximum length of input.

expression String EL expression to validate the input.

mask String Regular expression that the input must match.

minvalue double Minimum numerical value of input.

maxvalue double Maximum numerical value of input.

converter Class Type converter to use on the input.


Automatic maxlength on text inputs


public class SmartBindingActionBean extends BaseActionBean { @ValidateNestedProperties({ @Validate(field = "firstName", required = true, maxlength = 100), @Validate(field = "lastName", required = true, maxlength = 100) }) private User user; ... } <form action="/javapt09/SmartBinding.action" method="post"> <p> <label for="user.firstName">First name</label> <input id="user.firstName" maxlength="100" name="user.firstName" type="text" /> </p> <p> <label for="user.lastName">Last name</label> <input id="user.lastName" maxlength="100" name="user.lastName" type="text" /> </p> <p> <input name="print" value="Print" type="submit" /> </p> </form>


Custom Validation


@ValidationMethod public void validate(ValidationErrors errors) { if (user.getLastName().equals(user.getFirstName())) { errors.add("lastName", new SimpleError("First and last name must be different!")); } }


Displaying errors and messages

• Messages

• All errors

• Specific field error


<s:messages />

<s:errors />

<s:errors field="user.firstName" />

Features - Customizable URLs

Clean URLs


<servlet-mapping> <servlet-name>DispatcherServlet</servlet-name> <url-pattern>/action/*</url-pattern> </servlet-mapping>

@UrlBinding("/action/cleanURL/{$event}/{city}") public class CustomizableURLActionBean extends BaseActionBean { private String city; public Resolution delete() { ... } }

Features - Layouts

Reusable layout


<%@include file="/WEB-INF/jsp/common/taglibs.jsp" %> <s:layout-definition> <!DOCTYPE html> <html> <head> <meta charset="UTF-8" /> <title>${title}</title> <link rel="stylesheet" type="text/css" href="${contextPath}/css/style.css" /> </head> <body> <div id="header"> <span class="title">${title}</span> </div> <div id="body"> <s:layout-component name="body" /> </div> </body> </html> </s:layout-definition>

Features - Layouts

Using a reusable layout to render a page


<%@include file="/WEB-INF/jsp/common/taglibs.jsp" %> <s:layout-render name="/WEB-INF/jsp/common/layout-main.jsp" title="JavaPT09 - Stripes » Layouts"> <s:layout-component name="body"> <p>Main page content...</p> </s:layout-component> </s:layout-render>

Features - Layouts

Final result


<!DOCTYPE html> <html> <head> <meta charset="UTF-8" /> <title>JavaPT09 - Stripes » Layouts</title> <link rel="stylesheet" type="text/css" href="/javapt09/css/style.css" /> </head> <body> <div id="header"> <span class="title">JavaPT09 - Stripes » Layouts</span> </div> <div id="body"> <p>Main page content...</p> </div> </body> </html>

Features - Exception handling


<init-param> <param-name>DelegatingExceptionHandler.Packages</param-name> <param-value>com.example.javapt09.stripes.exception</param-value> </init-param>

public class DefaultExceptionHandler implements AutoExceptionHandler { public Resolution handle(Exception exception, HttpServletRequest request, HttpServletResponse response) { // Handle Exception return new ForwardResolution(ErrorActionBean.class); } public Resolution handle(IOException exception, HttpServletRequest request, HttpServletResponse response) { // Handle IOException return new ForwardResolution(ErrorActionBean.class); } }

Features - Exception handling

Don’t catch your exceptions


public Resolution handledException() throws IOException { throw new IOException("Handled exception"); } public Resolution unhandledException() throws Exception { throw new Exception("Unhandled exception"); }

Features - Interceptors

Built-in interceptors

Stripes request processing lifecycle stages:


@Before(stages = LifecycleStage.BindingAndValidation) public void prepareSomeStuff() { // load data from the DB }

RequestInit ActionBeanResolution HandlerResolution

BindingAndValidation CustomValidation EventHandling

ResolutionExecution RequestComplete

Features - Interceptors

Custom interceptors


public interface Interceptor { Resolution intercept(ExecutionContext context) throws Exception; }

@Intercepts(LifecycleStage.ActionBeanResolution) public class EJBInterceptor implements Interceptor { public Resolution intercept(ExecutionContext context) throws Exception { ... } }

Features - Easy Ajax integration


public class AjaxActionBean extends BaseActionBean { private List<String> cities = new ArrayList<String>(); public Resolution load() { return new JavaScriptResolution(cities); } }

<div id="cities"></div> <script type="text/javascript"> var client = new XMLHttpRequest(); client.open("GET", "${contextPath}/Ajax.action?load="); client.onreadystatechange = function() { if (this.readyState == 4) { var cities = eval(client.responseText); var citiesList = ""; for (var i = 0; i < cities.length; i++) { citiesList += "<li>" + cities[i] + "</li>"; } document.getElementById("cities").innerHTML = "<ul>" + citiesList + "</ul>"; } } client.send(null); </script>

Features - File download


public class DownloadActionBean extends BaseActionBean { @DefaultHandler public Resolution main() throws FileNotFoundException { String fileName = "stripes.png"; String filePath = getContext().getServletContext().getRealPath("/img/" + fileName); return new StreamingResolution("image/png", new FileInputStream(filePath)).setFilename(fileName); } }

Features - File upload

File upload form


<s:form beanclass="com.example.javapt09.stripes.action.UploadActionBean" enctype="multipart/form-data"> <p> <s:file name="fileBean" /> </p> <p> <s:submit name="upload" /> </p> </s:form>

Features - File upload

Saving the file


public class UploadActionBean extends BaseActionBean { private FileBean fileBean; public FileBean getFileBean() { return fileBean; } public void setFileBean(FileBean fileBean) { this.fileBean = fileBean; } @DefaultHandler public Resolution main() { return new ForwardResolution("/WEB-INF/jsp/file-upload.jsp"); } public Resolution upload() throws IOException { fileBean.getFileName(); fileBean.getSize(); fileBean.getContentType(); // fileBean.save(new File()); return new ForwardResolution("/WEB-INF/jsp/file-upload.jsp"); } }

Features - Extension/customization

• Stripes uses auto-discovery to find extensions

• The specified packages will be scanned for extensions like interceptors, formatters, type converters, exception handlers, etc


<init-param> <param-name>Extension.Packages</param-name> <param-value>com.example.javapt09.stripes.extensions</param-value> </init-param>

@Validate(maxlength = 100, converter = EmailTypeConverter.class) private String email;

Extensions

• Spring integration (built-in)http://www.stripesframework.org/display/stripes/Spring

+with+Stripes

• EJB3 integrationhttp://code.google.com/p/stripes-ejb3


Extensions

• Stripes Security (roles based)http://www.stripesframework.org/display/stripes/Securi

ng+Stripes+With+ACLs

• Stripes Security (custom authorization)http://www.stripesframework.org/display/stripes/Securit

y+Interceptor+for+custom+authorization


Extensions

• Stripes-Reload

Plugin for Stripes 1.5 that reloads modifications made to your Action Beans, Type Converters, Formatters, and Resource Bundles without having to restart your server

http://www.stripesbook.org/stripes-reload.html


Find more

• Stripes Framworkhttp://www.stripesframework.org

• Stripes Book: Stripes ...and Java Web Development Is Fun Again

http://www.pragprog.com/titles/fdstr


Q&A


Contacts

• Present Technologieshttp://www.present-technologies.com

• Bloghttp://www.samaxes.com

• Twitterhttp://twitter.com/samaxes


Documents

Stripes Java