Java EE Servlet JSP Tutorial- Cookbook 1
- 1. Java EE Servlet Tutorial First Cookbook- Getting started with Model 2: Servlet and JSP Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 2. Open%Source,%Reliable%and%Lightweight% Java%EE%Applica;on%Server% RESIN PRO Web Profile Health System Cloud Support Thursday, May 3, 12
- 3. Cookbook: Intro to Serlvets and JSP • This cookbook in the Java EE Servlet tutorial covers building a simple listing in JSP and Servlets. • This tutorial is part of Java EE Tutorial covering JSP_2.2, and Servlets 3.0. • The WIKI and step by step detailed instructions live here: • http://wiki4.caucho.com/ Building_a_simple_listing_in_JSP Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 4. About tutorial • Very liEle knowledge of HTML, Java and JSP is assumed • HTML and Java not covered length, but pointers in the right direc8on • Focus is Java Servlets and JSP (Java Server Pages) • Use whatever IDE you would like, but direc8ons focus on Eclipse Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 5. App you are building Sorting Remove Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 6. Sidebar: Why Eclipse? • Best? No not really, best is IntelliJ • Eclipse is free and supports Java EE well • NetBeans and JDeveloper are from Oracle, they are good too Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 7. Running tutorial app in Eclipse Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 8. Windows? Try Linux... • Java is write once run anywhere, so you can develop Java anywhere • Most companies deploy Java on some flavor of Linux • You can use Windows for development, but... • Probably a good idea to get familiar with produc8on deployment environment anyway • If you are a Windows or OSX users, I suggest installing Ubuntu (hEp:// www.ubuntu.com/) or CentOS on VMWare or Virtual Box and making that your main development environment • You can make this tutorial work for you on OSX and Windows, but might be beEer just to go with a fric8onless approach. This way you can focus on the concepts instead of the configura8on woes • Cloud deployment for the most part == Linux Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 9. Outline • 1 Optional: Getting started Eclipse Java EE IDE • 2 Resources • 3 What is going to be in the project • 4 Creating model and Repository objects for books • 4.1 Book model class • 4.2 Are you new to Java? • 4.3 BookRepository interface • 5 Servlets / JSP • 5.1 Servlet Background • 5.2 Creating your first Servlet • 5.2.1 BookListServlet listing • 5.2.2 Java EE / Servlets scopes (page, request, conversation, session, application) • 6 Creating your first JSP • 6.1 Templates/JSTL versus Java scriptlets • 6.1.1 /WEB-INF/pages/book-list.jsp listing • 6.1.2 HTML background • 6.1.3 JSTL c:forEach • 7 Setting up CDI • 7.1 CDI META-INF/beans.xml • 8 Deploying with Eclipse • 9 Deploying from the command line • 10 Cookbooks and Tutorials Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 10. Using Eclipse to setup Web Project • First go here to get Eclipse for Java EE: Install Guide for Eclipse for Java EE Indigo or higher. • Screenshots to follows, but here is the basic steps to installing Eclipse and Java EE development environment in one go • Using Eclipse Indigo or higher Install Resin (lightweight, fast, easy to use Java EE 6 Web Profile server) plugin: 1. Go to File menu -> New Project -> Dynamic Web Project 2. In New Dynamic Web Project Dialog-> New Runtime... 3. In New Runtime Dialog -> Download Additional Server Adapters -> Select Resin (Java EE Web Profile) 4.0.x 4. (Click Next and Ok until it installs Resin runtime) 5. (Eclipse needs to restart) Setup new Web Project in Eclipse 1. File -> New Project -> Dynamic Web Project 2. In New Dynamic Web Project Dialog-> New Runtime...->Select Resin->Check create local server checkbox 3. Step 2 of New Runtime...->Click Download and Install (you only have to do this once) 4. Fill out project name etc. (bookstore). 5. (Click Next and Ok until you are done) Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 11. Install Java EE 6 Web Profile • Go to File menu -‐> New Project -‐> Dynamic Web Project • In New Dynamic Web Project Dialog-‐> New Run8me... Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 12. Crea8ng a new web project • Click OK and Finish and Restart to restart Eclipse • Crea8ng a new Web Project Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 13. Crea8ng a simple Book lis8ng for our bookstore • Create a new Java class as follows: • Eclipse: Right Click "Java Resources" in Project Explorer -‐> New -‐> Class -‐> Package com.bookstore -‐> Class Name -‐> Book (That is the last 8me I will tell you how to create a class in Eclipse.) • Add 8tle, descrip8on, price, pubDate and id proper8es, and the toString and cloneMe methods as follows: Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 14. Are you new to Java? • If you are new to Java and the Book class seems foreign to you, • Read up on Java a bit Official Java tutorial. • Read the first three trails (Ge>ng Started, Learning the Java Language and EssenBal Java Classes), • Skip ahead to Java Beans. Skimming is ok. • If you have programmed before, most things you will pick up on your own. • Then come back here :) • Reminder: The methods public String getId() and public void setId(String id) would define a property called id Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 15. Repository Interface • First step in tutorial not going to actually talk to a database or use JDBC • For now, just using collec8on API • Repository object encapsulates how an object gets persisted, queried and updated (CRUD opera8ons) • Let’s define an interface for our CRUD opera8ons • Later we use JDBC/RDBMS (MySQL), JTA/RDBMS, JCache, MongoDB, etc. instead of collec8on API Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 16. BookRepository (DAO like object) • Eclipse: Right Click "Java Resources" in Project Explorer -‐> New -‐> Interface -‐> Package = com.bookstore -‐> Class Name = Book -‐> Click Finish Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 17. BookRepositoryImpl 1 of 4 • Actual BookRepositoryImpl just uses Java collec8on to store in memory (skim don’t read) Set’s up some test data Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 18. BookRepositoryImpl 2 of 4 • Helper methods to define test data, add method Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 19. BookRepositoryImpl 3 of 4 • Interface implementa8ons using collec8ons API Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 20. BookRepositoryImpl 4 of 4 • listBooks and removeBooks Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 21. BookRepositoryImpl wrap up • This BookRepositoryImpl really basic class. • Largely based on the collec8ons API • You can find out more informa8on about the Java collec8ons API at this tutorial trail. • A full discussion of collec8on API out of scope for cookbook • JDBC cookbook coming up in this tutorial series Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 22. @Applica8onScoped • One interesBng thing is BookRepositoryImpl uses @Applica2onScoped annotaBon • AnnotaBons allow you to add meta-‐data to Java objects. (To learn more see this annotaBons tutorial) • Applica2onScoped specifies a bean is applicaBon scoped • Scoping defines a lifecycle • how long an object will be around • ApplicaBonScoped means it will be around for the complete lifecycle of the Web ApplicaBon • This annotations has slightly different meanings depending on whether it is used with EJBs or Servlets. This annotation is part of the CDI support added to Java EE 6 to handle Java Dependency Injection. To learn more about CDI go see this tutorial Java Dependency Injection and this one part 2 both written by the same author that is writing this tutorial now. :) Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 23. @Applica8onScoped Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 24. Model done, now controller • Now that we have a model • Book, BookRepository • Lets define our web controller • Servlet controller • and view • JSPs Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 25. Servlet Background • A servlet is a Java class that handles HTTP requests • A Java web applica8on consists of one or more servlet bundled together with any JSPs and Java classes it needs into a war file (Web Applica8on Archive file). • Servlets run inside of a container (like Caucho's Resin) • End users typically use a Java Web Applica8on through a web browser like Apple Safari, Google Chrome, Mozilla FireFox or Internet Explorer Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 26. Crea8ng your first Servlet • Eclipse: Right Click "Java Resources" in Project Explorer -‐> New -‐> Servlet -‐> Package = com.bookstore.web -‐> Class Name = BookListServlet -‐> Click Next -‐> Remove URL mapping, create new mapping /book/ Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 27. Crea8ng your first Servlet (part 2) Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 28. BookListServlet • Note: This applica8on uses the REST style URL mappings • URLs that end in / imply you are working with a list • (like a directory of files). • URI /book/ implies a collecBon of books • Perfect since we want to show a list of books • Modify generated Servlet to only handle the doGet method • Change doGet method to forward to a JSP that we have not created yet that lives in WEB-‐INF Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 29. BookListServlet • Looks up books using bookRepo (injected with @Inject CDI) • Then forward to book-‐list.jsp to render book lis8ng Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 30. Why JSP is in WEB-‐INF • WEB-‐INF is a meta directory folder for war files. • JSPs in WEB-‐INF folder can never be loaded directly from a browser • This allows us to force all JSPs to first go through our Servlet 8er (controllers) which is essen8al for a model 2 architecture (a form of MVC tailored for HTTP applica8ons), • We use model 2 throughout the tutorial • Consider pumng JSPs in WEB-‐INF a best prac8ce. Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 31. @WebServlet annota8on (BookListServlet) • @WebServlet("/book/") allow us to map this Servlet to handle requests for the URI / book/ • @WebServlet annota8on is a new feature of Servlets 3.0 • Avoids a lot of XML configura8on Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 32. @Inject (BookListServlet) • Servlet uses repository model object to look up a list of BookRepository books. • Java dependency injec8on used to inject BookRepository into the Servlet • @Inject etc. added in Java EE 6 Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 33. doGet (BookListServlet) • Servlet is controller in model 2 • Controller talks to the model (BookRepository to get a list of Book), • doGet method gets called when somebody loads the page from the browser and corresponds to HTTP GET • doGet method uses the request object (HEpServletRequest request) to put the list of books into request scope using setAEribute as follows: request.setAttribute puts books into request scope. But what is a scope? Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 34. Understanding scopes • Servlets and Java EE have various scopes • page, request, conversa8on, session, applica8on • Page scope (10 to 200 milliseconds) • Request scope is around for one HTTP request (1/2 second to several seconds) • Session scope is around for the en8re user session (5 minutes to 90 minutes) • Conversa8on scope is around for one workflow (user registra8on, shopping cart, etc.). • Applica8on scope is around un8l web app shuts down Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 35. Background on JSP • JSP pages are also Servlets • JSP is a templa8ng language to define Servlets that allows you to focus on the HTML instead of the Java code • JSP is like a Servlet turned inside out • Essen8ally a JSP page is translated and compiled into a servlets • JSP is similar to ASP and PHP in concept and scope • ASP predates JSP and early JSP and ASP use a lot of the same concepts Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 36. JSP scriptlets versus Templates • JSP allows mixing Java code and HTML (called Java scriptlets), but don’t • JSP adopted more of a classic templa8ng approach like • Freemarker, Velocity and Smarty (PHP based templaBng) • Don’t allow mixing the programming language with the templaBng language • Allows the templaBng language to be a simple view logic language, • Keeps the templates smaller and more readable. • JSP uses JSTL and the Unified EL to accomplish things that Smarty, Freemarker and Velocity accomplish • Using JSTL/EL instead of Java scriptlets approach is a best prac8ce Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 37. Crea8ng a JSP in Eclipse Create a folder under WebContent/WEB-INF called pages Right click WebContent/WEB-INF/pages, then select New->JSP File use the file name book-list.jsp Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 38. Modify book-‐list.jsp to match the following Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 39. book-‐list.jsp page direc8ve • Let's break this down some. • First setup page using JSP page direc8ve: • page direc8ve sayshow we want the characters encoded and what the mime type of the page is. Consider it boiler plate for now Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 40. Using JSTL core library • Next we import the JSTL core library, under the tag c as follows: HTML background Most of the page is boiler plate and simple HTML. If you are new to HTML, try this HTML tutorial. Then come back here. Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 41. Using JSTL core c:forEach • Using c:forEach to iterate through the books in request scope ! <c:forEach var="book" items="${books}"> ! ! <tr> ! ! ! <td>${book.title}</td> ! ! ! <td>${book.description}</td> ! ! ! <td>${book.price}</td> ! ! ! <td>${book.pubDate}</td> ! ! </tr> ! </c:forEach> Syntax like${books}, ${book.title}, ${book.price} ${book.pubDate} is Unified EL. EL is expression language Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 42. JSTL c:forEach • Where did the books come from? • ${books} is the same books that we put into request scope in the //BookListServlet.doGet method ! ! request.setAttribute("books", bookRepo.listBooks()); ! ! <c:forEach var="book" items="${books}"> ! ! <tr> ! ! ! <td>${book.title}</td> ! ! ! <td>${book.description}</td> ! ! ! <td>${book.price}</td> ! ! ! <td>${book.pubDate}</td> ! ! </tr> ! </c:forEach> Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 43. Semng up Java Dependency Injec8on • To setup Java Dependency Injec8on (CDI), you need to create a beans.xml file • beans.xml need to go into META-‐INF • META-‐INF is a special directory for jar files and Java classpath entries to hold • beans.xml can be completely blank or just empty $ pwd ~/workspace/javaee-tutorial/bookstore/src/META-INF $ touch beans.xml To get Eclipse to quit complaining about the blank file not having the right format, fill it as follows: META-INF/beans.xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/ beans_1_0.xsd"> </beans> Note: the @Inject Java dependency injection will not work without this file. Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 44. Deploying applica8on with Eclipse • Deploying with Eclipse • Right click the BookListServlet in the Project Explorer • Choose Run As-‐>Run On Server... • "Select Manually Define a New Server" • Choose Resin-‐>Resin 4.0 from the Server List • Click "Download addi8onal Server adapters” Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 45. Deploying applica8on with Eclipse • Right click BookListServlet in project explorer then choose Run -‐> Run On Server • Select Resin then Click Next-‐> then click “Download and Install” Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 46. Applica8on Running in Eclipse Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 47. Applica8on Running in FireFox Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 48. Deploying from the command line Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12
- 49. End of first cookbook in tutorial • Cook books and Tutorials • Building a simple lis8ng in JSP: covers model 2, Servlets, JSP intro. <You just finished this one> • Java EE Servlet tutorial : Adding create, update and delete to the bookstore lisBng: covers more interacBons. • Java EE Servlet tutorial : Using JSPs to create header, footer area, forma>ng, and basic CSS for bookstore. • Java EE Servlet tutorial : Adding MySQL and JDBC to bookstore example.Java EE Servlet tutorial : Adding validaBon and JSP tag files to bookstore example. • Java EE Servlet tutorial : Adding I18N support to bookstore example. • Java EE Servlet tutorial : Load tesBng and health monitoring using bookstore example. • Java EE Servlet tutorial : Se>ng up clustering and session replicaBon. • Java EE Servlet tutorial : Se>ng up security for bookstore example. • Java EE Servlet tutorial : File uploads for bookstore example. • Java EE Servlet tutorial : Using JPA for bookstore example. • Java EE Servlet tutorial : Using JCache for bookstore example. Caucho Home | Contact Us | Caucho Blog | Wiki | Applica8on Server Thursday, May 3, 12