WEBSERVICE USING APACHE AXIS TUTORIAL-4 UNDERSTANDING APACHE AXIS

WEBSERVICE USING APACHE AXIS TUTORIAL-2
UNDERSTANDING APACHE AXIS
(part-4)(published in DeveloperIQ..April,2004) (www.developeriq.com)
R.S.RAMASWAMY (rs.ramaswamy@gmail.com)

APACHE AXIS-DEPLOYMENT USING WSDD FILE

In this part, we will follow the WSDD method. We have already created sqlaxisbean.java as explained in the last article. We used it as sqlaxisbean.jws (drop-in method). There was no necessity to compile this file.But in WSDD method (web-service deployment descriptor), we should compile this file.Next, we create the WSDD file. Then, we deploy this bean to tomcat. We may have to restart the tomcat4.1 webserver.

We can then create a java-console client and test the webservice. So, this is the step-by-step procedure. We will now go into the details involved here.We are now in c:\sam.

We give correct path, classpath etc. as in part-3.

set path=c:\windows\command;d:\jdk141\bin;

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// setcpath.bat

set classpath=c:\sam; d:\bea\weblogic700\lib\weblogic.jar;

c:\axis11\lib\axis.jar;

c:\axis11\lib\jaxrpc.jar;

c:\axis11\lib\saaj.jar;

c:\axis11\lib\commons-

logging.jar;

c:\axis11\lib\commons-

discovery.jar;

c:\axis11\lib\wsdl4j.jar;

c:\tomcat4.1\common\lib\

activation.jar;

c:\tomcat4.1\common\lib\xerces.jar

// sqlaxisbean.java

import java.sql.*;

import java.util.*;

import javax.ejb.*;

import javax.naming.*;

import java.rmi.*;

public class sqlaxisbean

{

String a;

public sqlaxisbean()

{

a="";

}

public String callejb(String s)

{

try

{

Properties props=new Properties();

props.put

(Context.INITIAL_CONTEXT_FACTORY,

"weblogic.jndi.WLInitialContextFactory");

String url="t3://127.0.0.1:7001";

props.put(Context.PROVIDER_URL,url);

Context context=new InitialContext(props);

System.out.println("context ok..");

sqlhome home=(sqlhome)context.lookup("sqlejbJndi");

System.out.println("home ok..");

sqlremote remote=home.create();

System.out.println("remote ok..");

a=remote.showdata(s);

System.out.println(a);

}catch(Exception e1)

{System.out.println(" "+e1);}

return a;

}

c:\sam>javac sqlaxisbean.java

so we get sqlaxisbean.class.

Copy this file to ‘d:\tomcat4.1\axis\web-inf\classes’ folder. (Note the difference from part-3 carefully.

In part-3, we just copied the file ‘sqlaxisbean.java’ to d:\tomcat4.1\webapps\axis folder. But, now we copy the class fil e to ‘d:\tomcat4.1\axis\web-inf\classes’ folder. We should now restart the tomcat server. Next, we create the WSDD file in c:\sam folder

Carefully note the following values that we have given:

a. service name “ejbsqlaxis”

b. provider “java:RPC”

c. class name “sqlaxisbean”

d. method name “callejb”

//c:\sam\sqlaxis.WSDD

<deployment

xmlns=”http://xml.apache.org/axis/WSDD/”

xmlns:java=”xml.apache.org/axis/WSDD/providers/java” >

<service name=”ejbsqlaxis”

provider=”java:RPC” >

<parameter name=”className”

value=”sqlaxisbean” />

<parameter name=”methodName”

value=”callejb” />

</service>

In Axis, a provider (also known as a pivot handler) is used for invoking the webservice class.

Axis provides the following provider types

i. RPC-based provider java:RPC

ii Message-based provider java:MSG

iii EJB provider java:EJB

(Currently, work is going on for developing COM provider.)

In the present demo, we are using RPC based provider.The next step is to deploy the bean in tomcat server. Please refer to page 38 of Axis by Romin Irani & Geelani Basha. WROX Press for further details.

c:\sam>java

org.apache.axis.client.AdminClientsqlaxis.WSDD

lhttp://localhost:8080/axis/services/AdminService

(Note: This is ‘l’ as in long and not ‘one’.)

(Remember that tomcat should be running. If tomcat server is not running, this command won’t work.)Wait till the message ‘Done Processing’ is displayed. It is essential to verify whether the bean has really been deployed correctly by the following command:

c:\sam>java org.apache.axis.client.AdminService list

–lhttp://localhost:8080/axis/services/AdminService

We will get the WSDD files of all the beans deployed. (If there are too many items, we can send the result to log.txt by the command :> (as before)> log.txt .We can then see log.txt and locate the ejbsqlaxis service, its classname and method name.Actually, our job is over. We can, now checkup, whether the bean is available as a webservice typing the URL in browser as: ‘http://localhost:8080/axis/services/Ejbsqlaxis?wsdl’ (ejbsqlaxis is the name given by us as the name of service in the WSDD file.) We will get the wsdl file (an xml file).Search for the occurrence of the port-type name as ‘sqlaxisbean’ and operation name as ‘callejb’.If these are found, it means that everything is fine.

Now we want to check up whether we can really use this service. For this, we create the following java console-mode program .

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// sqlaxisconsoleclient.java

import java.net.*;

import javax.xml.rpc.

ParameterMode;

import org.apache.axis.client.

Service;

import org.apache.axis.

client.Call;

import org.apache.axis.

encoding.XMLType;

import javax.xml.

namespace.QName;

public class

sqlaxisconsoleClient

{

public static

void main(String args[])

{

try

{

System.out.println

("Start");

Service service= new Service();

System.out.println

("Service ready");

Call call= (Call)service.createCall();

System.out.println

("call ready");

URL url=new URL("http://localhost:

8080/axis

/services/ejbsqlaxis");

// the last parameter is

service name & not class name!

call.setTargetEndpointAddress(url);

call.setOperationName("callejb”);

call.addParameter

("something", XMLType.XSD_STRING,

ParameterMode.IN);

call.setReturnType

(XMLType.XSD_STRING);

String r=

(String)call.invoke(new Object[]{args[0]});

System.out.println(r);

}catch(Exception e1){System.out.println(""+e1);}

}

If you carefully compare this file with the earlier jwsclient.java, you will find that except for the URL of the end-point, everything else is the same.We now compile this file.

c:\sam>javac sqlaxisconsoleclient.java

This compiles correctly.We can run this program:

c:\sam>java sqlaxisconsoleclient “select * from table1 where name like ‘d%’ “

We get the correct result. Now just a little explanation for the code!

1. We begin by defining the endpoint URL, which specifies the actual location of WEBSERVICE.

2. We specify the method name, then we create an instance of service and create CALL object for a service. We set URL and method name for this CALL object.

3. ‘addParameter’ method takes three parameters, viz.,

a. A user-defined name for the parameter (“sql” in our example).

b. Parameter datatype.

c. Whether the parameter is input parameter or output parameter.

4. It is now required to set the return type.

5. Finally, we invoke the call

That completes the fourth part of this tutorial. In the next month’s issue, we will directly use the EJB class files in WSDD file and invoke the EJB as webservice without using sqlaxisbean.

Continued in axis3.htm

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