Pro Spring MVC: With Web Flow potx

Deinum Serneels Shelve in Programming Languages / Java User level: Intermediate–Advanced www.apress.com SOURCE CODE ONLINE RELATED Pro Spring MVC: with Web Flow Get started building enterprise-quality web applications with Pro Spring MVC! This book takes you through the entire process of designing, implementing, and deploying a Java web application using Spring MVC and Spring Web Flow. It includes detailed analysis of the code and functionality, as well as numerous tips and tricks to help you get the most out of Spring MVC, Spring Web Flow, and web development in general. You’ll gain key practical knowledge and learn how you can apply similar designs and techniques to your own code. Right from the start, you’ll learn practical applications of the frameworks by using them with an application that is developed throughout the book. Each chapter defines real-world problems and solutions; solutions which you then use to upgrade the sample application. With Pro Spring MVC, you’ll learn how to: • Use the Spring MVC architecture • Develop with the DispatcherServlet • Configure your development environment • Deploy to a local web server and to a remote cloud-based deployment platform • Write controllers • Use Spring MVC with REST and Ajax • Resolve and implement views • Test your Spring MVC applications • Implement Spring Security • Build applications with Spring Web Flow Pro Spring MVC does more than simply cover the technical details, it fully explains many of the underlying concepts and gives you the practical knowledge you need to succeed. After reading this book, you’ll fully understand how to use Spring MVC to build your own web application from scratch or create a new web interface for an existing one. BOOKS FOR PROFESSIONALS BY PROFESSIONALS ® THE EXPERT’S VOICE ® IN SPING www.it-ebooks.info For your convenience Apress has placed some of the front matter material after the index. Please use the Bookmarks and Contents at a Glance links to access them. www.it-ebooks.info iv Contents at a Glance  Foreword xvi  About the Authors xviii  About the Technical Reviewer xx  Acknowledgments xxi  Introduction xxiii  Chapter 1: Configuring a Spring Development Environment 1  Chapter 2: Spring Framework Fundamentals 25  Chapter 3: Web Application Architecture 51  Chapter 4: Spring MVC Architecture 65  Chapter 5: Implementing Controllers 107  Chapter 6: Implementing Controllers — Advanced 177  Chapter 7: REST and AJAX 215  Chapter 8: Resolving and Implementing Views 237  Chapter 9: Testing Spring MVC Applications 273  Chapter 10: Spring Web Flow 321  Chapter 11: Building Applications with Spring Web Flow 373  Chapter 12: Advanced Spring Web Flow 429  Chapter 13: Spring Security 477  Appendix: Cloud Foundry: Deploying to the Cloud 535  Index 555 www.it-ebooks.info v Contents  Foreword xvi  About the Authors xviii  About the Technical Reviewer xx  Acknowledgments xxi  Introduction xxiii  Chapter 1: Configuring a Spring Development Environment 1 Prerequisites 1 Java Development Kit 2 Servlet Container 2 Integrated Development Environment 2 The Sample Application 2 A Bookstore Sample Application 3 The Build System 4 Building the Sample Application 6 Deploying the Sample Application 8 SpringSource Tool Suite (STS) 10 Configuring STS for Gradle projects 10 Importing the Sample into STS 12 Running the Application on the SpringSource vFabric tc Server 17 Editing the Application 19 Summary 22 www.it-ebooks.info C H A P T E R 1 1 Configuring a Spring Development Environment Before you can really start your journey into Spring MVC, you need to make sure you have your development environment set up right. This chapter will begin by walking you through that process. Next, it will provide some details about the sample bookstore application that ships with this book. But before going into either the details of the development environment or the sample application, this chapter will provide an overview of the prerequisites for your environment in general. The sample application that ships with the book is used to explain the concepts of Spring MVC and MVC in general. It is not intended to be a full-blown, ready-to-use production application; nor is it to be used as a Java or full Spring Framework application. The main intent of the app is to help explain and express the Spring MVC concepts used throughout the book. Prerequisites To build the sample application, you need to have a Java Development Kit (JDK) installed; and for (standalone) deployment, you need a servlet container that supports version 3.0 of the Servlet Specification (we chose to use Tomcat 7). To make development easier, you will need to use an integrated development environment (IDE); for this book, we, the authors, chose to use the SpringSource Tool Suite (STS). Table 1-1 lists the products and versions used while writing this book. Development on the selected products still continues, so it might be that there is a newer version available at the time you read this. However, there is nothing in the code that shouldn’t work on or with newer versions of the software. Table 1-1. Software Versions and Download Sites Product Version Download JDK 1.6.0 Update 31 www.oracle.com/technetwork/java/javase/downloads/index.html Tomcat 7.0.26 http://tomcat.apache.org/download-70.cgi SpringSource Tool Suite 2.9.0 www.springsource.com/developer/sts www.it-ebooks.info CHAPTER 1  CONFIGURING A SPRING DEVELOPMENT ENVIRONMENT 2 Java Development Kit The first ingredient is the Java Development Kit. JDK7 was recently released; however, it seems that JDK6 is still much more widely used, particularly in the enterprise. There are no known issues with running the sample application with JDK7, so those who want to “live on the edge” are free to do so. Those who want the smoothest ride possible should choose JDK6.  Note You may already have the Java Runtime Edition installed; however, you still need the Java Development Edition (JDK). The JRE is only for running Java applications, whereas the JDK is for compiling Java code. Servlet Container To run a Java web application, you need a web container. The sample application is using Servlet 3.0 features; and as such, you need a Servlet 3.0 capable web container. Tomcat (http://tomcat.apache.org/) is an excellent candidate and widely used in production systems. There is nothing Tomcat-specific in the sample file, so feel free to use Jetty, JBoss, Glassfish, or any other modern web container or application server.  Tip STS includes its own version of Tomcat called tc-server (www.vmware.com/products/vfabric- tcserver/). This is an excellent product built on top of Tomcat, and it offers value for both developer and production environments. Integrated Development Environment Although Spring itself doesn’t require a particular development environment (over and above the Java Development Kit), becoming familiar with a good IDE is highly recommended. Given Spring’s ubiquity in Enterprise Java development, excellent support for it can be found in the major IDEs like Eclipse (www.eclipse.org) and IntelliJ IDEA (www.jetbrains.com/idea/). SpringSource has also invested significant effort into providing its own distribution based upon Eclipse called the SpringSource Tool Suite (STS). And while the “vanilla” version Eclipse is excellent, STS provides additional levels of polish when it comes to developing Spring-based applications. The Sample Application This section delves into the sample application you will build throughout the book. For example, you will learn about the build system selected and used for the sample application. Next, you will learn how to import the sample application into STS and take your first steps in deploying the first part of the application. The main intent of the sample application is to show the features and possibilities of Spring MVC. Although Spring MVC is part of the Spring Framework, this application is not intended to provide full, www.it-ebooks.info CHAPTER 1  CONFIGURING A SPRING DEVELOPMENT ENVIRONMENT 3 in-depth coverage on all the features of the Spring Framework. If you want to read and learn more about the Spring Framework, we suggest checking out Pro Spring 3 (Apress, 2012). A Bookstore Sample Application The sample application that will be built and used throughout this book is a simple bookstore. You will learn how to add functionality for searching, displaying, and buying books. To buy books, the user of the app needs to have an account with the app’s associated bookstore, so there is also going to be some account registration and a login page. The sample application will remain more or less the same throughout the book. In the Spring Web Flow chapters, however, you’ll see some important differences that exist mainly to illustrate some of the Spring Web Flow functionality. You can find the code for the sample application with the source code for this book. Go ahead and download and extract it. Note that the top-level directory contains a number of folders entitled chapterX-bookstore. As you progress through this book, you will continually be adding new functionality to the sample application. In some cases, you will be revisiting code from previous chapters. For simplicity and clarity, the authors decided to separate each chapter’s progression into a separate project; to see the relevant code for Chapter X, simply load the project in the chapterX-bookstore folder. In addition to the directories for each chapter, you can also find two projects that are shared between all the book’s chapters (see Figure 1-1). These projects are called bookstore-shared and bookstore-web-resources, and they are shared with all projects. One project contains the shared business layer, while the other has the images, stylesheets, and other, similar files. Figure 1-1. An overview of the bookstore components  Note The project in chapterX-bookstore contains the solution for Chapter X. While this approach does have the downside of requiring you to load many projects into STS (one per chapter), it also means that you can see exactly how the application progresses—if you want to solve the problems in Chapter 7 yourself, then copy the Chapter 6 project and start working, using Chapter 7 as a reference point if you get stuck. www.it-ebooks.info CHAPTER 1  CONFIGURING A SPRING DEVELOPMENT ENVIRONMENT 4 For convenience, the root directory of the sample application for the relevant chapter (i.e., chapter1- bookstore for this chapter) will be referred to as SAMPLE_ROOT. The SAMPLE_ROOT will obviously be different for each chapter. The authors tried to create a realistic but simple sample application; to that end, we tried to use the technologies of today. For example, we use JPA 2.0 for the persistence layer, relying on Hibernate 4.1 for our specific implementation. For the web pages, the primary technology used is Java Server Pages (JSPs). A thorough tutorial on JSPs is outside the scope of this book; however, there are many good books on this topic available, such as Pro JSP 2 (Apress, 2005). You can also find a wealth of other resources for this technology, including Oracle’s own tutorial at http://download.oracle.com/javaee/5/tutorial/doc/bnagx.html.  Note The observant reader probably noticed the JEE5 bit in the tutorial URL. The JEE6 version of the tutorial covers JSF but not JSP; hence, the reference to the JEE5 tutorial. The Build System The topic of how to build applications has been subject to decades of arguments, fanaticism, and downright stupidity. We could have taken the easy way out and avoided this discussion by building and deploying entirely with the SpringSource Tool Suite (STS), which we will discuss later in this chapter. However, the authors felt that was a disservice to you. STS is sufficient for managing a developer’s workflow, but it isn’t quite sufficient for the operational management aspects. Typically, an application is built using one mechanism (the IDE), while an entirely different mechanism is used to deploy it to production. This is often a source of frustration, and it leads to the wonderful “works on my machine” syndrome. With this in mind, our strong opinion is that it is the developer’s responsibility to ensure that an application works in an environment as close to production as possible, including the build mechanism itself! You will see how sophisticated build tools make that possible. The build tool you are going to use in this book is Gradle (http://gradle.org). This is a fairly new but up-and-coming project-automation tool (project automation is a fancy term for build tool) that has a strong pedigree and has already established a very good reputation. A full discussion on build tools is outside the scope of this book; however, suffice it to say that Gradle combines the power of Maven’s “configuration over convention” approach with the succinctness of Groovy.  Note The Gradle project won the 2010 Springy Award for Most Innovative Product/Project 1 and was a finalist in the 2011 JAX Innovation Awards election. The Gradle infrastructure is driven by a build.gradle script (this is somewhat equivalent to Maven’s pom.xml) and an optional settings.gradle file; both can be found in the SAMPLE_ROOT directory. 1 http://www.springsource.org/node/2871 www.it-ebooks.info CHAPTER 1  CONFIGURING A SPRING DEVELOPMENT ENVIRONMENT 5  Tip If you prefer to use Maven, please note that Gradle is perfectly capable of generating Maven POMs (project object models). For more information, read “Maven POM generation” at http://gradle.org/maven_plugin.html. Dependency Management Java’s strength is its ecosystem. The wealth of high quality libraries is the currency used to pay for the language’s verbosity and pain. However, its greatest strength is, as ever, its greatest weakness: it isn’t unusual for small-to-medium projects to have a dependency graph of more than 50 libraries. This proliferation of libraries is made worse by the correct use of modularization! The problem with the dependencies is that the dependencies also have dependencies, which also have dependencies, which also Well, you probably get the point. There are direct dependencies (dependencies for the project) and transitive dependencies (dependencies needed by the direct dependencies). However, that isn’t the only problem because there is also something that could be called versioning hell. If there are multiple dependencies and these dependencies have a dependency on both library x and on different versions of that library, this presents an additional challenge. But, wait, there’s more! You don’t want to sit at your computer and Google for all the missing (transitive) dependencies, download them, redeploy your application, and then notice you have still another missing dependency (or maybe the wrong version of a dependency). Dependency management helps you out here. For example, it helps you with downloading and discovering what you need, and it tries to resolve all of the versioning conflicts. In this case, you can let the computer do the hard work for you, and you can focus at the task at hand, which is solving the business problem—selling books, in this book’s example (not searching for dependencies late into the night).  Note Gradle’s dependency management infrastructure is compatible with the somewhat industry-standard Maven repositories—and it has excellent support for resolving dependencies. The Gradle Build File Gradle is more than a dependency-management tool, as already mentioned. It is also a build tool; and, as such, it can do a lot for you. For example, if you open the build.gradle file, you’ll see the dependencies needed by all the subprojects. Gradle can also help you build (compile, test, and create a war archive) your application, and the Groovy language can be used to easily modify or influence the way you build your application. To help build the application, there is a plugin that can deploy the application to an embedded Tomcat instance. This instance can, in turn, be used to run the integration tests (see Chapter 9). www.it-ebooks.info CHAPTER 1  CONFIGURING A SPRING DEVELOPMENT ENVIRONMENT 6 These functions are just the beginning of what Gradle can provide. If you are interested in more complex builds, try reading the Gradle reference guide 2 or taking a look at the Gradle build 3 as used by the Spring Framework 4 (yes, even SpringSource uses Gradle). Building the Sample Application To build the sample, cd into the SAMPLE_ROOT directory and execute the gradlew script. Assuming you are on Unix system, this will look something like Figure 1-2. Figure 1-2. The initial build output You will notice the first thing that the gradlew script does is download the Gradle distribution itself! This is why there is no “install gradle” step—it is self-installing.  Note We recommend checking the gradlew script into source control. The Continuous Integration (CI) server and (as well as other developers) all use this script. Upgrading to a new version of Gradle is as simple as updating the gradlew script which, when executed, will silently upgrade itself. 2 http://www.gradle.org/docs/current/userguide/userguide.html 3 https://github.com/SpringSource/spring-build-gradle 4 https://github.com/SpringSource/spring-framework www.it-ebooks.info [...]... www.it-ebooks.info CHAPTER 2  SPRING FRAMEWORK FUNDAMENTALS Table 2-1 The Spring Framework Module Overview Module Artifact Description AOP spring- aop The proxy-based AOP framework for Spring spring-asm Repacked ASM to prevent conflicts with third-party library dependencies from ASM Aspects spring- aspects AspectJ-based aspects for Spring Beans spring- beans Spring s core bean factory support Context spring- context... import import import import com.apress.prospringmvc.moneytransfer.domain.Account; com.apress.prospringmvc.moneytransfer.domain.MoneyTransferTransaction; com.apress.prospringmvc.moneytransfer.domain.Transaction; com.apress.prospringmvc.moneytransfer.repository.AccountRepository; com.apress.prospringmvc.moneytransfer.repository.MapBasedAccountRepository; com.apress.prospringmvc.moneytransfer.repository.MapBasedTransactionRepository;... Spring with Struts 1.x applications Test spring- test Testing support classes 27 www.it-ebooks.info CHAPTER 2  SPRING FRAMEWORK FUNDAMENTALS Module Artifact Description Transactions spring- tx Transaction infrastructure classes Includes JCA integration and DAO support classes Web spring- web Core web package for use in any web environment Servlet spring- webmvc Spring MVC support package for use in a Servlet... Context spring- context-support Support classes for integrating third-party libraries with Spring Core spring- core Core utilities Expression Language spring- expression Classes for the Spring Expression Language (SpEL) Instrumentation spring- instrument Instrumentation classes to be used with a Java agent Instrumentation spring- instrument-tomcat Instrumentation classes specific to Apache Tomcat JDBC spring- jdbc... integration with the best-of-breed third-party frameworks It also provides easy extension points to write your own integration if you need one that doesn’t yet exist The framework was designed with developer productivity in mind, and it makes it easier to work with the existing, sometimes cumbersome Java and JEE APIs Before we start our journey into Spring MVC and Spring Web Flow, we will provide a quick... A SPRING DEVELOPMENT ENVIRONMENT Figure 1-15 The IndexController code Now replace (or modify) the code on the IndexController tab, as shown in Listing 1-1 Listing 1-1 The IndexController with the Model Attribute package com.apress.prospringmvc.bookstore .web; import org.springframework.stereotype.Controller; import org.springframework .web. bind.annotation.RequestMapping; import org.springframework .web. servlet.ModelAndView;... all projects However, the projects should eventually appear in STS (see Figure 1-11) Figure 1-11 STS after importing projects  Tip We suggest that you close the projects you aren’t currently working on To do this, select the projects to close, right-click, and then select the menu option, Close Project You can reopen a project by double-clicking it 16 www.it-ebooks.info CHAPTER 1  CONFIGURING A SPRING. .. course on Spring Core (formerly known as the Spring Framework) Spring is now a longtime de-facto standard for Java enterprise software development It introduced many of us to concepts such as dependency injection, aspect-oriented programming (AOP), and programming with plain-old-Javaobjects (POJOs) In this chapter, we will cover dependency injection and AOP Specifically, we will cover how the Spring Framework... use programming to our advantage To be able to do the things mentioned here, we will explore the Inversion of Control (IoC) container; the application context We will only touch on the necessary basics of the Spring Framework here If you want more in-depth information about it, we suggest the excellent Spring Reference guide (www.springsource.org) or books such as Pro Spring 3 (Apress, 2012) or Spring. .. to use Jetty, JBoss, Glassfish, or any other modern web container  Note With a view toward reducing the number of new things you must learn—if you’re more familiar with another web container, then it probably makes sense to stick with what you know for now Now copy the WAR file from SAMPLE_ROOT/build/libs/chapter1-bookstore-1.0.0.war to TOMCAT_ROOT/webapps If Tomcat hasn’t started, then start it by . Testing Spring MVC Applications 273  Chapter 10: Spring Web Flow 321  Chapter 11: Building Applications with Spring Web Flow 373  Chapter 12: Advanced Spring. implement views • Test your Spring MVC applications • Implement Spring Security • Build applications with Spring Web Flow Pro Spring MVC does more than