How to Display a JavaBean\'s List in JasperReports\' Detail Band?

JavaBeans Containing java.util.List: Display in JasperReports

Problem

A JavaBean contains a java.util.List. How can this list's data be displayed in the Detail band of a JasperReports document?

Solution

1. Use _THIS Expression: Utilize the _THIS expression to access the JavaBean's members.
2. Apply jr:list Component: Incorporate a jr:list component in the Detail band to iterate through the list's items.

Working Sample Code

// Java source to generate the report
...

// DataSource using JRBeanCollectionDataSource
private static JRDataSource getDataSource() {
    Collection<BeanWithList> coll = ...;
    return new JRBeanCollectionDataSource(coll);
}

// JavaBean
public class BeanWithList {
    private List<String> cities;
    // ...

    // Ensure a public getter for field extraction
    public List<String> getCities() {
        return this.cities;
    }
}

// jrxml file
...

// Subdataset for iterating through the list
<subDataset name="dataset1">
    <field name="city" class="java.lang.String">
        <fieldDescription><![CDATA[_THIS]]></fieldDescription>
    </field>
</subDataset>

// Detail band with jr:list component
<detail>
    ...
    <componentElement>
        <!-- jr:list component -->
        <jr:list ...>
            <datasetRun subDataset="dataset1">
                <!-- DataSource expression using JRBeanCollectionDataSource -->
                <dataSourceExpression><![CDATA[new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource($F{cities})]]></dataSourceExpression>
            </datasetRun>
            <jr:listContents ...>
                <textField ...>
                    <textFieldExpression><![CDATA[$F{city}]]></textFieldExpression>
                </textField>
            </jr:listContents>
        </jr:list>
    </componentElement>
    ...
</detail>
...

Results

This configuration generates a report displaying the list's data within the Detail band.

Additional Information

• Other relevant questions address this topic:

  • "How do I print a list of strings contained within another list in iReport?"
  • "Passing the List of primitive type objects as datasource for subreport"

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