当我尝试使用 JavaBean 数据源生成报告并在表中显示 Bean 的字段值时，PDF 报告显示空值。
我有一个简单的 bean (PersonBean)，如下所示:
public class PersonBean {
private String Field1;
private String Field2;
public String getField1() {
return Field1;
}
public void setField1(String field1) {
Field1 = field1;
}
public String getField2() {
return Field2;
}
public void setField2(String field2) {
Field2 = field2;
}
}
填充并返回 bean 集合的 Person 类如下:
import java.util.ArrayList;
import java.util.List;
public class Person {
public static java.util.List<PersonBean> getReportData() throws Exception {
List<PersonBean> personBeanList = null;
try {
personBeanList = new ArrayList<PersonBean>();
PersonBean personBean1 = new PersonBean();
personBean1.setField1("Hina");
personBean1.setField2("Sachdev");
personBeanList.add(personBean1);
PersonBean personBean2 = new PersonBean();
personBean2.setField1("Swathi");
personBean2.setField2("Singh");
personBeanList.add(personBean2);
} catch (Exception e) {
e.printStackTrace();
}
return personBeanList;
}
}
创建报告的PersonReport类如下:
import java.io.FileNotFoundException;
import java.util.*;
import net.sf.jasperreports.engine.*;
import net.sf.jasperreports.engine.data.JRBeanCollectionDataSource;
import net.sf.jasperreports.engine.design.JasperDesign;
import net.sf.jasperreports.engine.xml.JRXmlLoader;
import net.sf.jasperreports.view.JasperViewer;
public class PersonReport implements JRDataSource {
public static void main(String[] args) throws JRException, FileNotFoundException {
try {
Map<String, Object> params = new HashMap<String, Object>();
JasperDesign jasperDesign = JRXmlLoader.load("C:/Users/sachdevh/Desktop/reports/personReport.jrxml");
JasperReport jasperReport = JasperCompileManager.compileReport(jasperDesign);
JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, params,
new JRBeanCollectionDataSource(Person.getReportData()));
JasperExportManager.exportReportToPdfFile(jasperPrint, "./Util/bean.pdf");
JasperViewer.viewReport(jasperPrint);
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public Object getFieldValue(JRField arg0) throws JRException {
return null;
}
@Override
public boolean next() throws JRException {
return false;
}
}
通过使用iReport 4.6.0，我通过插入表格组件设计了一个报表。
jrxml 文件如下:
<?xml version="1.0" encoding="UTF-8"?>
<jasperReport ..>
<subDataset name="New Dataset 1" uuid="50bff6d9-9b98-444b-9851-bdd37ea570e4">
<queryString><![CDATA[]]></queryString>
<field name="field1" class="java.lang.String">
<fieldDescription><![CDATA[field1]]></fieldDescription>
</field>
<field name="field2" class="java.lang.String">
<fieldDescription><![CDATA[field2]]></fieldDescription>
</field>
</subDataset>
<parameter name="SUBREPORT_DIR" class="java.lang.String" isForPrompting="false">
<defaultValueExpression><![CDATA["C:\\Users\\sachdevh\\Desktop\\reports\\"]]></defaultValueExpression>
</parameter>
<parameter name="parameter1" class="java.lang.String">
<defaultValueExpression><![CDATA[$F{field1}]]></defaultValueExpression>
</parameter>
<queryString>
<![CDATA[]]>
</queryString>
<field name="field1" class="java.lang.String">
<fieldDescription><![CDATA[field1]]></fieldDescription>
</field>
<field name="field2" class="java.lang.String">
<fieldDescription><![CDATA[field2]]></fieldDescription>
</field>
<background>
<band splitType="Stretch"/>
</background>
<title>
<band height="79" splitType="Stretch"/>
</title>
<pageHeader>
<band height="35" splitType="Stretch"/>
</pageHeader>
<columnHeader>
<band height="61" splitType="Stretch">
<componentElement>
<reportElement uuid="b3e3e08d-91d9-4e01-ae74-abdfc270551a" key="table" x="0" y="0" width="555"
height="61"/>
<jr:table xmlns:jr="http://jasperreports.sourceforge.net/jasperreports/components"
xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports/components http://jasperreports.sourceforge.net/xsd/components.xsd">
<datasetRun subDataset="New Dataset 1" uuid="f5f39e4f-4349-4e5d-9736-03f84a7a7617">
<dataSourceExpression>
<![CDATA[new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource(Person.getReportData())]]></dataSourceExpression>
</datasetRun>
<jr:column uuid="9e2a6076-7f96-40c8-86ae-318b521a4f81" width="90">
<jr:tableHeader height="30"/>
<jr:tableFooter height="30"/>
<jr:columnHeader height="30">
<staticText>
<reportElement uuid="99411482-c1d5-44fa-aef7-9d9f4bf392ec" x="0" y="0" width="90"
height="30"/>
<textElement/>
<text><![CDATA[field1]]></text>
</staticText>
</jr:columnHeader>
<jr:columnFooter height="30"/>
<jr:detailCell height="20">
<textField>
<reportElement uuid="74861d9e-48a8-47ce-a477-81d4f497d483" x="0" y="0" width="90"
height="20"/>
<textElement/>
<textFieldExpression><![CDATA[$F{field1}]]></textFieldExpression>
</textField>
</jr:detailCell>
</jr:column>
<jr:column uuid="84c3b078-0114-452e-b3a3-f1c7dcd1b8cb" width="90">
<jr:tableHeader height="30"/>
<jr:tableFooter height="30"/>
<jr:columnHeader height="30">
<staticText>
<reportElement uuid="cb87f1a0-bbbf-40b2-bb19-292ecf8d9a18" x="0" y="0" width="90"
height="30"/>
<textElement/>
<text><![CDATA[field2]]></text>
</staticText>
</jr:columnHeader>
<jr:columnFooter height="30"/>
<jr:detailCell height="20">
<textField>
<reportElement uuid="84fd788f-24e8-4dfa-8c83-ce388c663f45" x="0" y="0" width="90"
height="20"/>
<textElement/>
<textFieldExpression><![CDATA[$F{field2}]]></textFieldExpression>
</textField>
</jr:detailCell>
</jr:column>
</jr:table>
</componentElement>
</band>
</columnHeader>
<detail>
<band height="125" splitType="Stretch"/>
</detail>
<columnFooter>
<band height="45" splitType="Stretch"/>
</columnFooter>
<pageFooter>
<band height="54" splitType="Stretch"/>
</pageFooter>
<summary>
<band height="42" splitType="Stretch"/>
</summary>
</jasperReport>
我认为下面的数据源表达式
<dataSourceExpression><![CDATA[new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource(Person.getReportData())]]></dataSourceExpression>
最佳答案
您可以通过两个步骤解决此问题:
- 将table组件移动到Title区域(现在它位于Column Header区域) - 防止在数据源有大量元素的情况下出现
net.sf.jasperreports.engine.JRRuntimeException:由于列标题溢出而导致无限循环创建新页面异常； - 将表的子数据集dataSourceExpression更改为与您的Java代码相关的以下值:
<datasetRun subDataset="New Dataset 1" uuid="f5f39e4f-4349-4e5d-9736-03f84a7a7617">
<dataSourceExpression><![CDATA[$P{REPORT_DATA_SOURCE}]]></dataSourceExpression>
</datasetRun>
关于java - 使用 JavaBean 数据源时在报告中获取空值，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12832965/