Issue with passing parameter to Jasper reports

Question

I have defined the following template:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE jasperReport
        PUBLIC "-//JasperReports//DTD Report Design//EN"
        "http://jasperreports.sourceforge.net/dtds/jasperreport.dtd">

<jasperReport name="HelloJasper_report">
    <parameter name="customer" class="com.eternity.model.Customer"/>
    <detail>
        <band height="20">
            <staticText>
                <reportElement x="220" y="0" width="200" height="20"/>
                <text><![CDATA[$P{customer.firstName}]]></text>
            </staticText>
        </band>
    </detail>
</jasperReport>

I am crateing the report with the following:

try{
    Map<String, Object> parameters = new HashMap<String, Object>();
    parameters.put("customer", new Customer("Example name"));

    System.out.println("Generating PDF...");
    JasperReport jasperReport =
            JasperCompileManager.compileReport("hellojasper.jrxml");
    JasperPrint jasperPrint =
            JasperFillManager.fillReport(jasperReport, parameters, new JREmptyDataSource());
    JasperExportManager.exportReportToPdfFile(
            jasperPrint, "HelloJasper.pdf");

    System.out.println("HelloJasper.pdf has been generated!");
}
catch (JRException e){
    e.printStackTrace();
}

where Customer is

public class Customer{

    private String firstName;

    public Customer(String firstName){
        this.firstName = firstName;
   }

}

However, the generated PDF just prints:

$P{customer.firstName}

What am I missing?

Answer 1

First of all, in your report you've declared a staticText block, which will print exactly the value from the text tag - that is why you're getting $P{person.firstName}.

In order to evaluate parameter and print it's value you should use textField with textFieldExpression in your report design:

<textField isBlankWhenNull = "true">
    <reportElement x="220" y="0" width="200" height="20"/>
    <textElement/>
    <textFieldExpression class = "java.lang.String">
        <![CDATA[$P{person}.firstName]]>
    </textFieldExpression>
</textField>

Secondly, you declared your person parameter to be an instance of class com.eternity.model.Person. Though in code you put Customer as a person parameter (and it doesn't seem to be a sublclass of Person). You have to:

1. either make your Customer a subclass of com.eternity.model.Person,
2. or change in your report design person parameter to be of class Customer with fully qualified package name (there is no package visible in your original answer).

And lastly: the firstName field has private modifier, so you should add a public getFirstName method to your class

public String getFirstName() {
    return this.firstName;
}

and then call <![CDATA[$P{person}.getFirstName()]]> in your report.