Web Service Using JAX WS

8/6/2019 Web Service Using JAX WS

1/59

Java Web Service


2/59

Objective

What Is a Web Service? Identifying Web Service Standards

JEE Web Service APIs

Using Java API for XML based-WS API (JAX-WS) Developing a Web Service by Using the Bottom-

Up Approach

Invoking the Web Service with a Java Client

Application

Developing a Web Service by Using the Top-

Down Approach


3/59

What is Service ?

A service is a behavior that is provided by a

component for use by any other component

based only on the interface contract.

A service has a network-addressable interface.

A service may be dynamically discovered and

used.


4/59


5/59


6/59


7/59


8/59

Service-oriented Architecture

SOA is a design and a way of thinking about building s/w components.


9/59

Benefits of SOA

Better reuse

Build new client functionality on top of existing

Business Services

Well defined interfaces

Make changes without affecting clients

Easier to maintain

Changes/Versions are not all-or-nothing

Better flexibility


10/59

What is aWeb Service?

In simpler terms

Software that performs a task.

Sits on a network so other systems can talk toit (most often SOAP over HTTP).

Has a defined, published interface (viaWSDL).

Is pla

tforma

nd la

ngua

ge independent. Typically uses XML.


11/59


12/59


13/59

Web service standards


14/59


15/59

Web services programming stack.

Web service stack is a collection of

standardized protocols and application

programming interfaces (APIs) that lets

individuals and applications locate and utilize

Web services.


16/59


17/59

Simple Object Access Protocol

SOAP is a lightweight protocol for exchange of information in a

decentralized, distributed environment.

It is an XML based protocol that consists of three parts:

1. SOAP envelope that defines a framework for describing what is in amessage

and how to process it.

2. SOAP encoding rules for expressing instances ofapplication-defined data types.

3. SOAP for representing remote procedure calls and responses.


18/59


19/59


20/59


21/59


22/59


23/59

SOAP Envelope the primary container

root element of the message using the XML namespace

http://schemas.xmlsoap.org/soap/envelope/ (As per SOAP 1.1spec.)

SOAP Header first immediate child element of a SOAP envelope

zero or more optional child elements mustUnderstand attribute

represents a transaction semantics entry

provide mechanisms to extend

defining high-level functionalities such as security, transactions,priority, and auditing


24/59

SOAP Header

The Header element is encoded as the first immediate child element of the

SOAP Envelope XML element. All immedia

te ch

ild elements of th

e Hea

derelement are called header entries.

The encoding rules for header entries are as follows:

1. A header entry is identified by its fully qualified element name, which

consists of the namespace URI and the local name.

2. The SOAP encodingStyle attribute MAY be used to indicate the encoding style

used for the header entries.

3. The SOAP mustUnderstand attribute.

5


25/59

SOAP Body SOAP envelopes child element

one or more optional SOAP body block entries

mandatory processing information or the payload intended for thereceiver

Body block can contain RPC method and its parameters

Target application (receiver) specific data

SOAP fault for reporting errors and status information

SOAP Fault error and/or status information

elements to define the error and status Faultcode (VersionMismatch, MustUnderstand, Client, Server)

Faultstring, Faultactor, Detail


26/59

SOAP mustUnderstand the processing of a SOAP header block is mandatory

or optional at the target SOAP node

SOAP Attachments

An XML format and any data format (can be ASCII orbinary)


27/59

Examples of SOAP Messages

SOAP Message Embedded in HTTP Request

POST /StockQuote HTTP/1.1

Host: www.stockquoteserver.com

Content-Type: text/xml; charset="utf-8"

Content-Length: nnnn

SOAPAction: "Some-URI"

L&T


28/59

SOAP Message Embedded in HTTP Response

HTTP/1.1 200 OKContent-Type: text/xml; charset="utf-8"Content-Length: nnnn

34.5


29/59

SOAP Communication

SOAP RPC remote procedural call-based synchronous

communication tightly coupled communication model based on

requests and responses.

SOAP Messaging

document-driven communication Using synchronous and asynchronous messaging

loosely coupled communication model based onmessage notification and the exchange of XMLdocuments


30/59


31/59

Web service Description Language -WSDL

Interface Definition Language (IDL) service based on XML that

defines the service interface and its implementation characteristics.WSDL document contains following (W3C spec):

Types a container for data type definitions using some type system

(suchas XSD).

Message an abstract, typed definition of the data being communicated.

Oper

ation

ana

bstra

ct description ofa

na

ction supported by th

eservice.

Port Typean abstract set of operations supported by one or more

endpoints.

Binding a concrete protocol and data format specification for a

particular port type.

Port a single endpoint defined as a combination ofa binding and anetwork address.

Service a collection of related endpoints.


32/59


33/59

The main structure of a WSDL document :

definition of types........

definition ofamessage....

definition ofa port.......

definition ofa binding....


34/59

WSDL Ports

The element is the most importantWSDL element.

It describes a web service, the operations that can be performed, and the

messages that are involved.

WSDL Messages

The element defines the data elements ofan operation.

Eachmessage can consist of one or more parts. The parts can be compared

to the parameters ofa function call in a traditional programming language.

WSDL Types

The element defines the data types that are used by the web

service.

For maximum platform neutrality, WSDL uses XML Schema syntax to define

data types.

WSDL Bindings

The element defines the message format and protocol details for

each port.


35/59

UDDI

The Universal Description, Discovery, and Integration (UDDI) specifications

define how to publishand discover information about services in a UDDI-conforming registry.

The UDDI schema identifies the types of XML data structures that comprise an

entry in the registry for a service.

UDDI registry as a "Yellow Pages" for web services.

Web services uses UDDI for discovery and lookup services.


36/59

WSDL

Web Service(J2EE, PL/SQL,

.NET,C/C++,

Legacy )

Web Service(J2EE, PL/SQL,

.NET,C/C++,

Legacy )

Web ServiceClient

(J2EE, .NET,

PL/SQL )

Web ServiceClient

(J2EE, .NET,

PL/SQL )

Points to

description

Describes

Service

Finds

Service

Invokes with

XML Messages

BasicWeb Services

SOAP

UDDI

Registry

Points toservice


37/59


38/59


39/59


40/59


41/59

Building Web Services with JAX-WS


42/59

What is JAX-WS


43/59

JAX-WS is a technology for building web services and

clients that communicate using XML.

JAX-WS allows developers to write message-oriented as well as RPC-oriented web services.

In JAX-WS, a remote procedure call is represented

by an XML-based protocol suchas SOAP.


44/59

Why JAX-WS ?

Platform independence of the Java programming

language.

JAX-WS client can access a web service that is not

running on th

e Ja

va

pla

tform,a

nd vice versa

.It provides a complete Web services stack that eases

the task of developing and deployingWeb services.

JAX-WS also includes the Java Architecture for XML

Binding (JAX

B)a

nd SOAP with

Atta

ch

ments API for Ja

va

(SAAJ).


45/59

JAX-WS speeds up Web services development by

providing a library of annotations to turn plain old

Java object (POJO) classes into Web services.

It also specifies a detailed mapping from a service

defined in the Web Services Description Language

(WSDL) to the Java classes that implement that

service.


46/59

JAX-WS supports two approaches

Contract first: Start withaWSDL contract, and

generate a Java class to implement the service.

Code first: Start witha Java class, and useannotations to generate bothaWSDL file and a

Java interface.


47/59


48/59


49/59


50/59


51/59


52/59


53/59


54/59


55/59

Creating a Simple Web Service and Client with JAX-WS


56/59

Developing a JAX-WS web service is a Java class annotated with

the javax.jws.WebService annotation.

The @WebService annotation defines the class as a webservice endpoint.

A service endpoint interface (SEI) is a Java interface that

declares the methods that a client can invoke on the service.

An SEI is not required when building a JAX-WS endpoint. The

web service implementation class implicitly defines a SEI.


57/59

Use the endpoint implementation class and

The wsgen tool to generate the web service artifacts

and the stubs that connect a web service client to the

JAX-WS runtime.


58/59

Basic steps for creating the web service and client:

Code the implementation class.Compile the implementation class.

Deploy the WAR file. The tie classes (whichare used to

communicate with clients) are generated by the Application

Server during deployment.

Code the client class.Use wsimportto generate and compile the stub files.

Compile the client class.

Run the client.


59/59

Thank You

Web Service Using JAX WS

Documents

Transcript of Web Service Using JAX WS