How to Display a JavaBean\'s List Data in a Jasper Report\'s Detail Band?

JRBeanCollectionDataSource: Displaying Data from a java.util.List in JavaBeans

Introduction

JavaBeans often contain collections of data. JRBeanCollectionDataSource allows you to display data from these collections in a variety of ways.

Question

How can I display data from a java.util.List stored in a JavaBean in the Detail band of a Jasper report?

Answer

Key Considerations for Solution:

• Use the _THIS expression to access the JavaBean object.
• Utilize the List (jr:list) component within the Detail band.

Implementation

Java Class:

// JavaBean with a list of strings
public class BeanWithList {
  private List<String> cities;
  private Integer id;

  // Getter methods
}

JRXML:

<jasperReport>
  <subDataset name="dataset1">
    <field name="city" class="java.lang.String">
      <fieldDescription><![CDATA[_THIS]]></fieldDescription>
    </field>
  </subDataset>
  <field name="id" class="java.lang.Integer"/>
  <field name="cities" class="java.util.Collection"/>

  <title>
    <staticText>Bean with List sample</staticText>
  </title>

  <detail>
    <textField>
      <reportElement x="0" y="0" width="100" height="20"/>
      <textFieldExpression><![CDATA[$F{id}]]></textFieldExpression>
    </textField>
    <componentElement>
      <reportElement x="100" y="0" width="400" height="20"/>
      <jr:list>
        <datasetRun subDataset="dataset1">
          <dataSourceExpression><![CDATA[new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource($F{cities})]]></dataSourceExpression>
        </datasetRun>
        <jr:listContents height="20" width="400">
          <textField>
            <reportElement x="0" y="0" width="100" height="20"/>
            <textFieldExpression><![CDATA[$F{city}]]></textFieldExpression>
          </textField>
        </jr:listContents>
      </jr:list>
    </componentElement>
  </detail>
</jasperReport>

Result

This approach will generate a report displaying the id field of the JavaBean, as well as the contents of the List elements within a subreport component in the Detail band.

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