Developing RESTful Services with Spring

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Fay Cooper
5 years ago
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2 Overview This course combines four main parts: several chapters of study on the Spring core module; a module on Spring MVC and how to use it for REST development; coverage of Spring persistence techniques, with a focus on JPA and REST; and a short unit on testing with Spring. The latter two include some general-purpose content more in the persistence chapters, less in the testing chapter but then are focused on REST web services from there. 2

3 Timeline Day 1 2½ hours Module 1, Chapter 1 2 hours Module 1, Chapter 2 2 hours Module 1, Chapter 3 Day 2 3 hours Module 1, Chapter 4 1½ hours Module 1, Chapter 5 1 hours Module 2, Chapter 0 2 hours Module 2, Chapter 1 (spans days) Day 3 2 hours Module 2, Chapter 2 2 hours Module 2, Chapter 3 2 hours Module 2, Chapter 4 (spans days) Day 4 1½ hours Module 2, Chapter 5 2½ hours Module 2, Chapter 6 1 hour Module 2, Chapter 7 1½ hours Module 2, Chapter 8 Day 5 2 hours Module 2, Chapter 9 2 hours Module 2, Chapter 10 2½ hours Module 2, Chapter 11 It s a pretty packed week! You may need to save some time by converting some labs into examples (i.e. review the answer code instead of doing them step-by-step), or cutting chapters that are of less interest. 3

4 Teaching Notes I hope that the coursebook is sufficiently clear and detailed, and so the following notes just capture a few ideas about how to approach a given topic, additional concepts to add to your lectures and discussions, and any surprises you might encounter. Module 1, Chapter 2 An interesting side note that you might make during or after the Singleton vs. Singleton exercise: in order to enforce singularity (or prototype behavior) even over the rules set by a Java developer, Spring has to carry out some privileged actions. For this to work, either there must be no security manager in place, or it must have a policy that allows the Spring codebase some special permissions. A rough list is here: permission java.io.filepermission "", "read"; permission java.io.filepermission "-", "read,write"; permission java.util.propertypermission "*", "read"; permission java.net.socketpermission " "connect"; permission java.lang.runtimepermission "accessdeclaredmembers"; permission java.lang.reflect.reflectpermission "suppressaccesschecks"; 4

5 Module 1, Chapter 4 This chapter introduces two features that may land with a bit of a thud in some classes: autowiring, and auto-detection of annotated component classes. The previous chapter did introduce component scanning, so that we could hook methods. But now we look at both of these features in detail. Autowiring is controversial: used heavily by many in the Spring community but reviled and labeled outright bad practice at many companies. We try not to advocate one way or the other here, but simply to cover the feature completely and accurately. Component scanning and annotation processing is a different choice entirely, although this and autowiring are often practiced together. Like autowiring, component scanning seems to tear away some of the declarative benefit of Spring; annotation processing is another matter but where the kingpin annotation seems to we do wind up in the same boat. It might be worthwhile to point out that other sorts of annotation post-processors can enable features that even the anti-autowire crowd may find more appealing, such for the web tier for DAOs. Module 1, Chapter 5 One note on the Policy demo: to accommodate the different concrete paths at which the code is deployed, code in other courseware modules often rely on the CC_MODULE environment variable, and various beans will on their own initiative expand the phrase ${env.cc_module} found in their property values by looking up this variable. But that seems a bit much for this exercise, and so the exact path of the code source must be entered when configuring the policy. This is simple enough and the path is shown in the demo instructions. But the demo answer will have a path from the Examples tree, so any copyand-paste solution will need some additional editing. It also means that course deployments to non-standard roots (other than c:\capstone) will require editing of the XML file, even for the answer code. Finally, note that this syntax is demanding: the trailing slash matters, and even incorrect case for the drive spec ( C vs. c ) will result in a failure to match the permission. Read and type carefully! 5

6 Module 2, Chapter 0 In this chapter I m looking to lay out the big ideas of REST so as to set the stage for what is mostly a course in how to build services, using Spring. Not every group will need this REST primer, so it s broken out here, and hence the choice of zero as the chapter number. Module 2, Chapter 10 Note that the BillingClient application will not test out perfectly against the later versions of the Billing service found in this and the final chapter. Once we move to the database, the invoice IDs hard-coded into the client will not be found. This doesn t present as a problem in running the course as written, but if someone were to go back to test out the client application, or were to deploy the latest steps of the service and client from a standing start, they would see the issue. (In a future revision I ll probably add a third step to the client application just to address this.) 6

7 Revision History Version4.1 updates the course for Spring 4.1, and expands the content. Major changes: A new Chapter 5 on building services with Java generics. A new Chapter 7 on to provide muliple representations of the same Java object(s). The persistence chapters have been pulled over from Course 117B and re-worked, just about from scratch. There are new exercises, expanded coverage of JdbcTemplate, new coverage of TransactionTemplate, and some more compelling illustrations of transaction issues, including isolation level and transaction propagation. The testing chapter has been updated and expanded to cover the MockMvc feature that came in with Spring 3.2. Version 3.1 is the initial release of this course, but modules 1 and 3 are borrowed from Course 117A. Troubleshooting If you run into any trouble with code exercises, the first and best thing to do is to doublecheck that the classroom machines have been set up precisely according to the course setup guide. Especially, the wrong version of a tool can cause significant problems; don t wander off-book in this way unless absolutely sure you can support the software that you prefer and that we haven t tested. Check environment variable settings carefully, too; these are the cause of a great many classroom glitches. Below are some specific pitfalls that have come up in previous offerings of the course: Be certain you have taken the few steps indicated in the Tools and Environment pages in the first chapter of the coursebook, such as editing the SetEnvironment script and certain workspace settings to fit any non-standard locations on student machines. 7

8 Errata The following issues were discovered after the most recent release, and will be addressed on the next maintenance cycle: [Nothing yet!] Feedback We very much appreciate whatever feedback we can get on our courseware especially from the instructor s perspective. Naturally, the more specific, the better, and we strongly encourage you to make notes on issues you may encounter in the classroom, whether they re typos, missing files, or suggestions for clearer language to explain a concept. We can t guarantee that we ll act on every suggestion, but we re aggressive about stamping out problems and try to be highly responsive. Hopefully this means that when you give us good feedback, you get a better course the next time you need to teach it. Please direct all courseware feedback to Will Provost Capstone Courseware mailto:provost@capcourse.com For anyone who s interested, we have a very informal defect-tracking system, based in Excel spreadsheets with columns to capture defect location, nature, status, and author feedback. Ultimately, feedback goes into these sheets, so if you want a template, we ll be happy to provide one, to facilitate the reporting process. 8

Introduction to Spring

Introduction to Spring Version 4.1 Instructor s Guide Copyright 2006-2015 Capstone Courseware, LLC. All rights reserved. Overview This course provides an overview of Spring, wandering onto the territory