Print, Export and Page Navigation Buttons in the Report

Question

When I view a report through CR4E, the generated report has 3 buttons namely Print, Export and Page Navigation buttons. But when I click on either of the buttons I get a 'null pointer exception'. This is a critical error as I am unable to navigate past the first page. Do I have to add code to these buttons? If not, why am I getting an error? Kindly solve my problem as soon as possible.

Answer 1

<p>Looking at your code it appears that you are storing the ReportSource in session prior to passing in the ResultSet. This will create a problem when a postback is made on  the viewer page (which all of the viewer actions do). If you look at the sample code which is generated when you use the JSP Page Wizard you will notice that the ResultSet is passed to the ReportClientDocument object prior to it being stored in session. Then, when the page is called again this object is retrieved and the ReportSource is used by the viewer. You can quickly run the test using one of our sample reports to see what I am talking about. The code below was generated using the Consolidated Balance Sheet.rpt and did not experience any problems doing any of the viewer actions.</p><%@page import="com.businessobjects.samples.JRCHelperSample,<br />com.crystaldecisions.report.web.viewer.CrystalReportViewer,<br />com.crystaldecisions.reports.sdk.ReportClientDocument,<br />com.crystaldecisions.sdk.occa.report.application.OpenReportOptions,<br />com.crystaldecisions.sdk.occa.report.lib.ReportSDKExceptionBase,<br />com.crystaldecisions.sdk.occa.report.reportsource.IReportSource,<br />java.sql.Connection,<br />java.sql.DriverManager,<br />java.sql.ResultSet,<br />java.sql.SQLException,<br />java.sql.Statement"%><%<br /><br /><br />    try {<br /><br />        String reportName = "Sample Reports/Consolidated Balance Sheet.rpt";<br />        ReportClientDocument clientDoc = (ReportClientDocument) session.getAttribute(reportName);<br /><br />        if (clientDoc == null) {<br /><br />            clientDoc = new ReportClientDocument();<br />            <br />            // Open report<br />            clientDoc.open(reportName, OpenReportOptions._openAsReadOnly);<br /><br />  <br />            {<br />                // **** POPULATE MAIN REPORT ****<br />                {<br />                     // Connection Info for fetching the resultSet<br />                    String connectStr = "jdbc:derby:classpath:/Xtreme";<br />                    String driverName = "org.apache.derby.jdbc.EmbeddedDriver";<br />                    String userName = "dbuser";        // TODO: Fill in database user<br />                    String password = "dbpassword";    // TODO: Fill in valid password<br /><br />                    String query = "SELECT CUSTOMER_NAME FROM APP.CUSTOMER WHERE COUNTRY = &#39;Australia&#39;";<br /><br />                    <br />                    String tableAlias = "FINANCIALS";        // TODO: Change to correct table alias<br /><br />                     <br />                    JRCHelperSample.passResultSet(clientDoc, fetchResultSet(driverName, connectStr, userName, password, query),<br />                        tableAlias, "");<br />                }<br /><br /><br />            }<br />        <br />            // Store the report document in session<br />            session.setAttribute(reportName, clientDoc);<br /><br />        }<br /><br /><br />            {<br />                // Create the CrystalReportViewer object<br />                CrystalReportViewer crystalReportPageViewer = new CrystalReportViewer();<br /><br />                //    set the reportsource property of the viewer<br />                IReportSource reportSource = clientDoc.getReportSource();                <br />                crystalReportPageViewer.setReportSource(reportSource);<br /><br />                // set viewer attributes<br />                crystalReportPageViewer.setOwnPage(true);<br />                crystalReportPageViewer.setOwnForm(true);<br /><br />                // Process the report<br />                crystalReportPageViewer.processHttpRequest(request, response, application, null); <br /><br />            }<br />            <br /><br />    } catch (ReportSDKExceptionBase e) {<br />        out.println(e);<br />    } <br />    <br />%><%!<br />// Simple utility function for obtaining result sets that will be pushed into the report.  <br />// This is just standard querying of a Java result set and does NOT involve any <br />// Crystal JRC SDK functions. <br /><br />    private static ResultSet fetchResultSet(String driverName,<br />            String connectStr, String userName, String password, String query) throws SQLException, ClassNotFoundException {<br /><br />        //Load JDBC driver for the database that will be queried    <br />        Class.forName(driverName);<br /><br />        Connection connection = DriverManager.getConnection(connectStr, userName, password);<br />        Statement statement = connection.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);<br /><br />        //Execute query and return result sets<br />        return statement.executeQuery(query);<br /><br />}%><p>Try using the code generated from the wizard to see if it works for you as well. </p><p>Regards,<br />Sean Johnson (CR4E Product Manager) </p>