advjhtp1_29 soap.ppt

7/27/2019 advjhtp1_29 soap.ppt

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2002 Prentice Hall. All rights reserved.

Chapter 29: Introduction to Web

Services and SOAP

Outline

29.1 Introduction

29.2 Simple Object Access Protocol (SOAP)

29.3 SOAP Weather Service


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29.1 Introduction

SOAP Simple Object Access Protocol

Promote interoperability

Communication among different software systems.

Provides XML communication in many Web services Web Services

Exposes public interfaces usable by Web applications


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29.2 Simple Object Access Protocol

(SOAP)

SOAP HTTP-XML-based protocol

Enables application to communicate over Internet

Uses XML documents called messages

SOAP message contains an envelope Describes messages content and intended recipient

Ability to make aRemote Procedure Call(RPC)

Request to another machine to run a task


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Outline

Fig. 29.1 ClassSimpleService.

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1 // Fig. 29.1: SimpleService.java2 // Implementation for the requested method on the server34 public class SimpleService {56 public String getWelcome( String message ) throws Exception7 {

8 String text =9 "Welcome to SOAP!\nHere is your message: " + message;1011 return text; // response12 }13 }

Class SimpleService

resides on a server

Method returns a String when

invoked; this method is made

available to remote clients


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(SOAP) (cont.)

Fig. 29.2 SOAP package administration tool.


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(SOAP) (cont.)

Fig. 29.3 Description of deployed service.


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Outline

Fig. 29.4 Clientmaking a SOAP

request (part 1).

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1 // Fig. 29.4 : GetMessage.java2 // Program that makes a SOAP RPC34 // import Java packages5 import java.io.*;6 import java.net.*;7 import java.util.*;

89 // import third-party packages10 import org.apache.soap.*;11 import org.apache.soap.rpc.*;1213 public class GetMessage {1415 // main method16 public static voidmain( String args[] ) {17 String encodingStyleURI = Constants.NS_URI_SOAP_ENC;18 String message;1920 if ( args.length != 0 )21 message = args[ 0 ];22 else23 message = "Thanks!";24

25 // attempt SOAP remote procedure call26 try {27 URL url = new URL(28 "http://localhost:8080/soap/servlet/rpcrouter" );2930 // build call31 Call remoteMethod = new Call();32 remoteMethod.setTargetObjectURI(33 "urn:xml-simple-message" );

34

Client for the RPC

SOAP-implementation APIs

Specify encodingstyle used for

SOAP message

Specify URL of server

to which the client sends

the SOAP message

Instantiate Call

object and set its URI


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Outline

Fig. 29.4 Clientmaking a SOAPrequest (part 2).

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35 // set name of remote method to be invoked36 remoteMethod.setMethodName( "getWelcome" );37 remoteMethod.setEncodingStyleURI( encodingStyleURI );3839 // set parameters for remote method40 Vector parameters = new Vector();41

42 parameters.addElement( new Parameter( "message",43 String.class, message, null ) );44 remoteMethod.setParams( parameters );45 Response response;4647 // invoke remote method48 response = remoteMethod.invoke( url, "" );4950 // get response51 if ( response.generatedFault() ) {52 Fault fault = response.getFault();5354 System.err.println( "CALL FAILED:\nFault Code = "55 + fault.getFaultCode()+ "\nFault String = "56 + fault.getFaultString() );57 }58

59 else {60 Parameter result = response.getReturnValue();6162 // display result of call63 System.out.println( result.getValue() );64 }65 }66

Build parameters usedto invoke method

getWelcome of classSimpleService

Invoke methodgetWelcome and

store returned valuein Response object

Display message iferror occurred

Display remote

methods returned value

if no problems occurred


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Outline

Fig. 29.4 Clientmaking a SOAPrequest (part 3).

67 // catch malformed URL exception68 catch ( MalformedURLException malformedURLException ) {69 malformedURLException.printStackTrace();70 System.exit( 1 );71 }7273 // catch SOAPException

74 catch ( SOAPException soapException ) {75 System.err.println( "Error message: " +76 soapException.getMessage() );77 System.exit( 1 );78 }79 }80 }

java GetMessageWelcome to SOAP!Here is your message: Thanks!

java GetMessage "my messageWelcome to SOAP!

Here is your message: my message


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29.3 SOAP Weather Service

SOAP Weather Service Web service

Modification of RMI-based Weather Service (Chapter 13)

Use SOAP RPC instead of Java RMI

Send information from server to client


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Outline

Fig. 29.5 SOAPimplementation ofclassWeather-Service (part 1).

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1 // Fig. 29.5: WeatherService.java2 // WeatherService provides a method to retrieve weather3 // information from the National Weather Service.4 package com.deitel.advjhtp1.soap.weather;56 // Java core packages7 import java.io.*;

8 import java.net.URL;9 import java.util.*;1011 publicclass WeatherService {1213 private Vector weatherInformation; // WeatherBean objects1415 // get weather information from NWS16 privatevoidupdateWeatherConditions()17 {18 try {19 System.out.println( "Update weather information..." );2021 // National Weather Service Travelers Forecast page22 URL url = new URL(23 "http://iwin.nws.noaa.gov/iwin/us/traveler.html" );24

25 // set up text input stream to read Web page contents26 BufferedReader in = new BufferedReader(27 new InputStreamReader( url.openStream() ) );2829 // helps determine starting point of data on Web page30 String separator = "TAV12";3132 // locate separator string in Web page33 while ( !in.readLine().startsWith( separator ) )

34 ; // do nothing35

ClassWeatherService provides

method getWeatherInformationthat classWeatherServiceClient

calls through SOAP RPC


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Outline


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36 // strings representing headers on Travelers Forecast37 // Web page for daytime and nighttime weather38 String dayHeader =39 "CITY WEA HI/LO WEA HI/LO";40 String nightHeader =41 "CITY WEA LO/HI WEA LO/HI";42

43 String inputLine = "";4445 // locate header that begins weather information46 do {47 inputLine = in.readLine();48 }while ( !inputLine.equals( dayHeader ) &&49 !inputLine.equals( nightHeader ) );5051 weatherInformation = new Vector(); // create Vector5253 // create WeatherBeans containing weather data and54 // store in weatherInformation Vector55 inputLine = in.readLine(); // get first city's data5657 // The portion of inputLine containing relevant data58 // is 28 characters long. If the line length is not at59 // least 28 characters long, then done processing data.

60 while ( inputLine.length() >28 ) {6162 // Prepare strings for WeatherBean for each city.63 // First 16 characters are city name. Next, six64 // characters are weather description. Next six65 // characters are HI/LO or LO/HI temperature.66 weatherInformation.add(67 inputLine.substring( 0, 16 ) );68 weatherInformation.add(

69 inputLine.substring( 16, 22 ) );

Add Strings parsed from

Travelers ForecastWeb

page toVector


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Outline


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70 weatherInformation.add(71 inputLine.substring( 23, 29 ) );7273 inputLine = in.readLine(); // get next city's data74 }7576 in.close(); // close connection to NWS Web server

7778 System.out.println( "Weather information updated." );79 }8081 // process failure to connect to National Weather Service82 catch( java.net.ConnectException connectException ) {83 connectException.printStackTrace();84 System.exit( 1 );85 }8687 // process other exceptions88 catch( Exception exception ) {89 exception.printStackTrace();90 System.exit( 1 );91 }92 }93

94 // implementation for WeatherService interface method95 public Vector getWeatherInformation()96 {97 updateWeatherConditions();9899 return weatherInformation;100 }101 }

Method getWeatherInformation

is made available to remote clients


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Outline

Fig. 29.6 SOAPimplementation ofclassWeather-ServiceClient

(part 1).

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1 // Fig. 29.6: WeatherServiceClient.java2 // WeatherServiceClient accesses the WeatherService remote3 // object via SOAP to retrieve weather information.4 package com.deitel.advjhtp1.soap.weather;56 // Java core packages7 import java.util.*;

8 import java.net.*;910 // Java extension packages11 import javax.swing.*;1213 // third-party packages14 import org.apache.soap.*;15 import org.apache.soap.rpc.*;1617 // Deitel packages18 import com.deitel.advjhtp1.rmi.weather.*;1920 publicclass WeatherServiceClient extends JFrame {2122 // WeatherServiceClient constructor23 public WeatherServiceClient( String server )24 {

25 super( "SOAP WeatherService Client" );2627 // connect to server and get weather information28 try {2930 // URL of remote SOAP object31 URL url = new URL( "http://" + server + ":8080/soap/"32 + "servlet/rpcrouter" );33

Set SOAP services URL


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Outline


(part 2).

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34 // build SOAP RPC call35 Call remoteMethod = new Call();36 remoteMethod.setTargetObjectURI(37 "urn:xml-weather-service" );3839 // set name of remote method to be invoked40 remoteMethod.setMethodName(

41 "getWeatherInformation" );42 remoteMethod.setEncodingStyleURI(43 Constants.NS_URI_SOAP_ENC );4445 // invoke remote method46 Response response = remoteMethod.invoke( url, "" );4748 // get response49 if ( response.generatedFault() ) {

50 Fault fault = response.getFault();5152 System.err.println( "CALL FAILED:\nFault Code = "53 + fault.getFaultCode() + "\nFault String = "54 + fault.getFaultString() );55 }5657 else {

58 Parameter result = response.getReturnValue();5960 Vector weatherStrings = ( Vector )61 result.getValue();6263 // get weather information from result object64 List weatherInformation = createBeans(65 weatherStrings );66

Instantiate Call

object and set its URI

Invoke remote method

getWeatherInfomationand store returned value in

Response object

Display message iferror occurred

Display remote

methods returned

value as List if noproblems occurred


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Outline


(part 3).

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67 // create WeatherListModel for weather information68 ListModel weatherListModel =69 new WeatherListModel( weatherInformation );7071 // create JList, set its CellRenderer and add to72 // layout73 JList weatherJList = new JList( weatherListModel );

74 weatherJList.setCellRenderer( new75 WeatherCellRenderer() );76 getContentPane().add( new77 JScrollPane( weatherJList ) );78 }7980 } // end try8182 // handle bad URL

83 catch ( MalformedURLException malformedURLException ) {84 malformedURLException.printStackTrace();85 }8687 // handle SOAP exception88 catch ( SOAPException soapException ) {89 soapException.printStackTrace();90 }9192 } // end WeatherServiceClient constructor9394 // create List of WeatherBeans from Vector of Strings95 public List createBeans( Vector weatherStrings )96 {97 List list = new ArrayList();

CovertVector ofStringsto List ofWeatherBeans


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Outline


(part 4).

98 for ( int i = 0; ( weatherStrings.size() - 1 ) > i;99 i += 3 ) {100 list.add( new WeatherBean(101 ( String ) weatherStrings.elementAt( i ),102 ( String ) weatherStrings.elementAt( i + 1 ),103 ( String ) weatherStrings.elementAt( i + 2 ) ) );104 }

105106 return list;107 }108109 // execute WeatherServiceClient110 publicstaticvoidmain( String args[] )111 {112 WeatherServiceClient client = null;113

114 // if no server IP address or host name specified,115 // use "localhost"; otherwise use specified host116 if ( args.length == 0 )117 client = new WeatherServiceClient( "localhost" );118 else119 client = new WeatherServiceClient( args[ 0 ] );120121 // configure and display application window122 client.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );123 client.pack();124 client.setResizable( false );125 client.setVisible( true );126 }127 }



29.3 SOAP Weather Service (cont.)

Fig. 29.7 Apache SOAP Admin page.




Fig. 29.8 Apache SOAPService Deployment Descriptor Template.


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Fig. 29.9 SOAP WeatherService Client.

advjhtp1_29 soap.ppt

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