CICS Transaction Gateway V5 The WebSphere ... - IBM Redbooks

358 CICS Transaction Gateway V5
The action of the HTML form is to call the servlet CTGTesterCCIServlet, using
the POST method to send the parameters. This means that the parameters are
sent in the HTTP request body. Because an HTTP POST request is intended to
affect some sort of change on the Web server, a Web browser will prompt to
resubmit the data if the user clicks Refresh on the results page. Conversely, the
GET method could be used, which sends the parameters on the HTTP request
URL. Because HTTP GETs are not intended to alter anything on the Web server,
the results page of such a request can be refreshed without a prompt being
shown.
Servlet
In the following section, we describe the major code sections in the
CTGTesterCCIServlet servlet and how the servlet functions. The servlet is stored
in the CTGTesterCCIWeb enterprise application project in WebSphere Studio.
The servlet is defined to be in the package itso.cics.j2ee.eci.testercci. It is
stored in the folder source/itso/cics/j2ee/eci/testercci in WebSphere Studio.
Figure B-20 shows the import statements used to give us access to the Java
packages used in the servlet. The import of javax.servlet and
javax.servlet.http give us access to the Java Servlet API set of classes; the
import of javax.naming gives us access to the JNDI library; the import of
javax.rmi gives us access to the Java Remote Method Invocation library; the
imports of java.io, java.util, and java.text are required for utility classes
used in the servlet; the import of com.ibm.ctg.client provides the CICS TG
Java class library.
import javax.servlet.http.*;
import javax.servlet.*;
import javax.naming.*;
import javax.rmi.*;
import java.util.Date;
import java.util.StringTokenizer;
import java.io.UnsupportedEncodingException;
import java.io.IOException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
Figure B-20 Import statements
Figure B-21 shows the opening code section of our servlet. We extend the
HTTPServlet class to make our class an HTTP protocol servlet. Following this we
then first declare our instance variables and objects, which are variables that we
wish to share across all threads running within the servlet.