Downloaded 73 times
![The original document
{"baz": "qux", "foo": "bar"}
The patch
[
{ "op": "replace", "path": "/baz", "value": "boo"
},
{ "op": "add", "path": "/hello", "value": ["world"]
},
{ "op": "remove", "path": "/foo"}
]
The result
{"baz": "boo","hello": ["world"]}](https://image.slidesharecdn.com/javaee8recipes-161123121901/85/Java-EE-8-Recipes-47-320.jpg)
![The original document
{"baz": "qux", "foo": "bar"}
The patch
[
{ "op": "replace", "path": "/baz", "value": "boo"
},
{ "op": "add", "path": "/hello", "value": ["world"]
},
{ "op": "remove", "path": "/foo"}
]
The result
{"baz": "boo","hello": ["world"]}](https://image.slidesharecdn.com/javaee8recipes-161123121901/75/Java-EE-8-Recipes-47-2048.jpg)
Uploaded byJosh Juneau
Java EE 8 Recipes
The document presents an overview of Java EE 8 and its enhancements over Java EE 7, highlighting productivity increases, new standards, and solutions to common real-life problems developers face. Key topics include the use of Java 8 features, JSF 2.3 improvements, JSON processing with JSR-374, and CDI 2.0 advancements. It emphasizes practical recipes for developers to quickly implement new functionalities while encouraging reference to online documentation for deeper learning.
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Java EE 8 Recipes
- 1. Java EE 8Recipes Presented By: Josh Juneau Author and Application Developer
- 2. About Me Josh Juneau DayJob: Developer and DBA @ Fermilab Night/Weekend Job: Technical Writer - Java Magazine and OTN - Java EE 7 Recipes - Introducing Java EE 7 - Java 8 Recipes JSR 372 EG and JSR 378 EG Twitter: @javajuneau
- 3. Agenda - Take alook at big picture of Java EE 8 - Resolve a series of real life scenarios using the features of Java EE 7 and Java EE 8
- 4. Before we start.. . Old: J2EE Modern: Java EE
- 5. Java EE ofthe Past (J2EE) Difficult to Use Configuration Verbose Few Standards
- 6.
- 7. Java EE 7Increases Productivity Even More and Introduces Standards for Building Modern Applications
- 8. Java EE 7Increased Productivity • CDI Everywhere • JAX-RS Client API,Async Processing • BeanValidation in EJBs and POJOs • JSF Flows • JMS 2.0 - Much Less Code
- 9. Java EE 7Introduced New Standards • WebSockets • JSON-P • Batch API • Concurrency Utilities for Java EE
- 10.
- 11. Java EE 8Continues this Momentum • Continued enhancements for productivity and web standards alignment • Cloud enhancements • Better alignment with Java SE 8 • Work towards a better platform for development of microservices
- 13.
- 14. Recipes! Statement for Completeness: Recipesare not meant to provide comprehensive coverage of the features. Rather, they are meant to get you up and running with the new functionality quickly, providing the details you need to know. To learn more details on any of the features covered, please refer to the online documentation. Let’s Cook!
- 15. How to Run Settingup your environment for Java EE 8 • Payara 5 Branch • Clone git repository and build: mvn clean install -DskipTests • Clone and Build/Download latest EA of Spec • Most have git repositories
- 16. JSF 2.3 JSR 372 •New features added in JSF 2.3, adding more flexibility • Improved CDI Alignment • PostRenderViewEvent • WebSocket Integration and Ajax Enhancements • Java 8 Date-Time Support • Enhanced Components • Much More
- 17. Problem #1 You wouldlike to work with the Java 8 Date- Time API via your JSF application. Does not work with Java EE 7 out of the box.
- 18. Solution Make use ofthe <f:convertDateTime /> tag.
- 19. How it Works JSF2.3 requires a minimum of Java 8, so we can make use of Java 8 goodness. New type attribute values on <f:convertDateTime>: • localDate, localTime, localDateTime • offsetTime,offsetDateTime, zonedDateTime
- 20. Problem #2 Oftentimes, youneed to work with FacesContext or another JSF artifact. It can be cumbersome to obtain the current instance, ServletContext, etc. time after time.
- 21. Problem FacesContext context = FacesContext.getCurrentInstance(); ExternalContextexternalContext = FacesContext.getCurrentInstance().getExter nalContext();
- 22. Problem Map<String, Object> cookieMap= FacesContext.getCurrentInstance().getExternalContext() .getRequestCookieMap(); Map<String, Object> viewMap = FacesContext.getCurrentInstance().getViewRoot( ).getViewMap();
- 23. Solution Inject JSF artifactsin JSF 2.3, and inject into JSF artifacts.
- 24. Solution @Inject private ExternalContext externalContext; @Inject privateServletContext servletContext; @Inject @ViewMap private Map<String, Object> viewMap;
- 25. How it Works JSF2.3 provides default producers for many of the most commonly used JSF artifacts, therefore, we can now inject rather than hard-code. Converters, validators and behaviors are now also injection targets.
- 26.
- 27. BeanValidation JSR-380 New Features inBeanValidation 2.0: • Focus on Java SE 8 Features • Type annotations, Date-TimeValidation, etc. • Simpler Constraint Ordering on Single Properties • Custom Payload for ConstraintViolations
- 28. Problem #3 You wouldlike to validate dates and times utilizing the Java 8 Date-Time API to ensure that they are in the past or in the future.
- 29. Solution @Future and @Pastwill work with Java 8 Date-Time
- 30. How it Works •Place validation constraint annotations on a field, method, or class such as a JSF managed bean or entity class. • When the JSF Process Validations phase occurs, the value that was entered by the user will be validated based upon the specified validation criteria. At this point, if the validation fails, the Render Response phase is executed, and an appropriate error message is added to the FacesContext. However, if the validation is successful, then the life cycle continues normally. • Specify a validation error message using the message attribute within the constraint annotation
- 31. How it Works OtherNew Features: Type-use annotation: List<@NotNull @Email String> emails; Mark standardized constraints with @Repeatable, eliminating the need for the usage of the @Size.List pattern.
- 32. JSON-P 1.1 JSR-374 The JavaAPI for JSON Processing is a standard for generation and processing of JavaScript Object Notation data. JSON-P provides an API to parse, transform, and query JSON data using the object model or the streaming model. JSON is often used as a common format to serialize and deserialize data for applications that communicate with each other over the Internet.
- 33. JSON-P 1.1 • Addsnew JSON standards for JSON-Pointer and JSON-Patch • Provides editing operations for JSON objects and arrays • Helper classes and Java SE 8 Support
- 34. Problem #4 You wouldlike to build a JSON object model using Java code. We wish to create a list of current reservations.
- 35. Solution Utilize JSON Processingfor the Java EE Platform to build a JSON object model containing all of the current reservations.
- 36.
- 37. How it Works JSONdefines only two data structures: objects and arrays.An object is a set of name-value pairs, and an array is a list of values. JSON defines seven value types: string, number, object, array, true, false, and null.
- 38. How it Works JavaEE includes support for JSR 353, which provides an API to parse, transform, and query JSON data using the object model or the streaming model Make use of JsonObjectBuilder to build a JSON object using the builder pattern. Call upon the Json.createObjectBuilder() method to create a JsonObjectBuilder.
- 39. How it Works Utilizethe builder pattern to build the object model by nesting calls to the JsonObjectBuilder add() method, passing name/value pairs.
- 40. How it Works Itis possible to nest objects and arrays. The JsonArrayBuilder class contains similar add methods that do not have a name (key) parameter. You can nest arrays and objects by passing a new JsonArrayBuilder object or a new JsonObjectBuilder object to the corresponding add method. Invoke the build() method to create the object.
- 41. Problem #5 You areinterested in finding a specific value within a JSON document.
- 42. Solution Utilize JSON Pointerto find the desired value.
- 43. How it Works •Create a new JsonPointer object and pass a string that will be used for identifying a specific value.
- 44. How it Works •Obtain the value by calling the JsonPointer.getValue() method and passing the JsonObject you wish to parse. The JsonValue will contain the value to which you had pointed.
- 45. Problem #6 You wouldlike to perform an operation on a a specified value within a JSON document.
- 46. Solution Utilize JSON Patchto replace a specified value within a JSON document with another value.
- 47. The original document {"baz":"qux", "foo": "bar"} The patch [ { "op": "replace", "path": "/baz", "value": "boo" }, { "op": "add", "path": "/hello", "value": ["world"] }, { "op": "remove", "path": "/foo"} ] The result {"baz": "boo","hello": ["world"]}
- 48.
- 49. How it Works •JSON Document or JsonPatchBuilder • JSON Pointer is used to find the value or section that will be patched • A series of operations can be applied
- 50. Problem #7 You wishto parse some JSON using Java.
- 51. Solution Use the JsonParser,which is a pull parser that allows us to process each document record via iteration.
- 52. How it Works Parsercan be created on a byte or character stream by calling upon the Json.createParser() method. Iterate over the JSON object model and/or array, and parse each event accordingly.
- 53. JSON-B JSR-367 Java API forJSON Binding • Standardize means of converting JSON to Java objects and vice versa • Default mapping algorithm for converting Java classes • Draw from best of breed ideas in existing JSON binding solutions • Provide JAX-RS a standard way to support “application/json” for POJOs • JAX-RS currently supports JSON-P
- 54. Problem #8 You wouldlike read in a JSON document and map it to a Java class or POJO.
- 55. Solution Utilize default JSONbinding mapping to quickly map to a POJO.
- 56.
- 57. Solution Create JSON fromJava object
- 58. Solution Create JSON fromJava List
- 59. How it Works •JSON-B API provides serialization and deserialization operations for manipulating JSON documents to Java • Default mapping, with custom annotation mapping available for compile-time • JsonConfig class for runtime mapping customizations
- 60. CDI 2.0 JSR 365 •JSR is in active progress…can download WELD betas and test • Java SE Bootstrap • XML Configuration • Asynchronous Events • @Startup for CDI Beans • Portable Extension SPI Simplification • Small features/enhancements
- 61. Problem #9 You’d liketo mark a CDI event as asynchronous.
- 62. Solution Fire the eventcalling upon the fireAsync() method, passing the event class.
- 63. Solution Use @ObservesAsync toobserve an asynchronous event.
- 64. How it Works •Utilizes the Java 8 Asynchronous API to provide a streamlined approach. • @ObservesAsync annotation added to annotate an observer method parameter so that existing observers annotated with @Observes would remain synchronous. • fireAsync() added to the Event interface.
- 65. Configuration New Spec Pending •Standard for externalizing configuration • Aimed at cloud-based environments • Provide the ability to change one or more configurations that are independent/decoupled of apps...multiple configuration files • Unified API for accessing configuration in many different environments • Layering and overrides
- 66. Problem #10 The applicationthat you are developing requires some external configuration values for specifying server-side paths and/or resources.
- 67. Solution Use the standardizedconfiguration API to retrieve the configuration values. Suppose you have a property file with the following values: city=Chicago language=Java
- 68. Solution Config config =ConfigProvider.getConfig(); String city = config.getProperty(“city”); String language = config.getProperty(“language”); Long val = config.getProperty(“someLong”, Long.class);
- 69. How it Works •Define the configuration sources for an application using a config-sources.xml file, or using an api to set up at deployment time.
- 70. WebSockets The Java APIfor WebSocket provides support for building WebSocket applications. WebSocket is an application protocol that provides full-duplex communications between peers over the TCP protocol. What about Java EE 8??
- 71. Problem #11 You wishto create a communication channel that can be used to receive messages asynchronously.
- 72. Solution Create a WebSocketendpoint by annotating a POJO class using @ServerEndpoint, and providing the desired endpoint path. Create a message receiver method, and annotate it with @OnMessage
- 73.
- 74. How it Works Createa WebSocket endpoint by annotating a class with @ServerEndpoint, and passing the value attribute with a desired path for the endpoint URI. @ServerEndpoint(value=“/chatEndpoint”) URI: ws://server:port/application-name/path
- 75. How it Works Methodannotated @OnOpen is invoked when the WebSocket connection is made. Method annotated @OnMessage is invoked when a message is sent to the endpoint. It then returns a response.
- 76. How it Works Specifyoptional Encoder and Decoder implementations to convert messages to and from a particular format.
- 77. How it Works Exampleof a Decoder:
- 78. JAX-RS 2.1 JSR 370 •Hypermedia API • Reactive API • Security API • Support for SSE (Server Sent Events) • Improved CDI Integration • Support for Non-Blocking IO in Providers
- 79. Problem #12 You wouldlike to initiate an open-ended communication channel from a server to clients. You wish to have a connection remain open to the client so that subsequent single- sided communications from the server can be sent.
- 80. Solution Create an SSEResource using JAX-RS 2.1, and broadcast server messages to connected clients at will.
- 81.
- 82. How it Works •Try now by downloading Jersey 2.24 • Similar to long-polling, but may send multiple messages • Annotate resource method with @Produces(SseFeature.SERVER_SENT_EVE NTS) • Also possible to broadcast using SseBroadcaster
- 83. MVC 1.0 Features ofMVC 1.0: • Action-based • Follows suit of Spring MVC or Apache Struts • Does not replace JSF • No UI Components • Model: CDI, BeanValidation, JPA • View: Facelets, JSP, other • Controller: Layered on top of JAX-RS
- 84. We’ve Covered ALot …but there is a lot more to cover!!!!
- 85. Microservices? What is amicroservice? How to do micro services with Java EE? We’ll get there in Java EE 9…
- 86. Learn More Code Examples:https://github.com/juneau001/AcmeWorld Contact on Twitter: @javajuneau