为什么要得到多个图表而不是一个带序列的图表？

Question

以下是答案：How to create multiple charts of same type but with different dataseries using JRBeanCollectionDatasource in Jasperreports

我设法至少使用嵌套列表创建了图表。我的Java对象：

public class PoolUserLoginsVO {
    private int userLogins;
    private String poolId;
    private Date date;

    //constructor + getter/setters

userLogins是y坐标值，图表是时间序列图，因此x坐标是日期。 poolId是坐标所属的系列。

我获得了每个系列所需的值列表，并且由于有多个系列，因此我有一个列表列表，该列表传递给Jasper Reports的参数映射。

我的碧玉报告：

主要碧玉（整个文件很长，所以只有相关部分）：

<?xml version="1.0" encoding="UTF-8"?>
<!-- Created with Jaspersoft Studio version 6.10.0.final using JasperReports Library version 6.10.0-unknown  -->
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="test" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="fbaeab5e-6793-456e-9567-e0c5af982904">
    <property name="com.jaspersoft.studio.data.defaultdataadapter" value="One Empty Record"/>
    <parameter name="poolLogins" class="java.util.List"/>
    <queryString>
        <![CDATA[]]>
    </queryString>
    <background>
        <band splitType="Stretch"/>
    </background>
    <detail>
        <band height="223">
            <subreport>
                <reportElement x="0" y="0" width="550" height="200" uuid="9f8a2d4a-1d90-4f88-a08c-1ea2604360c5"/>
                <dataSourceExpression><![CDATA[new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource($P{poolLogins})]]></dataSourceExpression>
                <subreportExpression><![CDATA["sub_charts.jasper"]]></subreportExpression>
            </subreport>
        </band>
    </detail>
</jasperReport>

$ P {poolLogins}是List<List<PoolUserLoginsVO>。

sub_charts.jasper：

<?xml version="1.0" encoding="UTF-8"?>
<!-- Created with Jaspersoft Studio version 6.10.0.final using JasperReports Library version 6.10.0-unknown  -->
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="sub_charts" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="bc8c76ba-0b85-4522-bf67-4c62ae87202b">
    <field name="_THIS" class="java.util.List">
        <fieldDescription><![CDATA[_THIS]]></fieldDescription>
    </field>
    <detail>
        <band height="237" splitType="Stretch">
            <subreport>
                <reportElement x="0" y="20" width="540" height="200" uuid="1ec1f733-ffee-46f3-859c-f774e5277d19"/>
                <dataSourceExpression><![CDATA[new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource($F{_THIS})]]></dataSourceExpression>
                <subreportExpression><![CDATA["sub_chart.jasper"]]></subreportExpression>
            </subreport>
        </band>
    </detail>
</jasperReport>

sub_chart.jasper：

<?xml version="1.0" encoding="UTF-8"?>
<!-- Created with Jaspersoft Studio version 6.10.0.final using JasperReports Library version 6.10.0-unknown  -->
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="sub_chart" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="4ce41625-c60b-4759-acbe-5fe12a013fb2">
    <queryString>
        <![CDATA[]]>
    </queryString>
    <field name="userLogins" class="java.lang.Integer"/>
    <field name="poolId" class="java.lang.String"/>
    <field name="date" class="java.util.Date"/>
    <background>
        <band splitType="Stretch"/>
    </background>
    <detail>
        <band height="210" splitType="Stretch">
            <timeSeriesChart>
                <chart evaluationTime="Report">
                    <reportElement x="0" y="20" width="540" height="180" uuid="874eee5e-1e71-4870-906b-ef71ef91d274"/>
                    <chartTitle/>
                    <chartSubtitle/>
                    <chartLegend/>
                </chart>
                <timeSeriesDataset>
                    <timeSeries>
                        <seriesExpression><![CDATA[$F{poolId}]]></seriesExpression>
                        <timePeriodExpression><![CDATA[$F{date}]]></timePeriodExpression>
                        <valueExpression><![CDATA[$F{userLogins}.intValue()]]></valueExpression>
                    </timeSeries>
                </timeSeriesDataset>
                <timeSeriesPlot>
                    <plot/>
                    <timeAxisFormat>
                        <axisFormat labelColor="#000000" tickLabelColor="#000000" axisLineColor="#000000"/>
                    </timeAxisFormat>
                    <valueAxisFormat>
                        <axisFormat labelColor="#000000" tickLabelColor="#000000" axisLineColor="#000000"/>
                    </valueAxisFormat>
                </timeSeriesPlot>
            </timeSeriesChart>
        </band>
    </detail>
</jasperReport>

PDF和图表成功生成。但是有两个问题：

1）即使只有4个系列，我也会得到30页的图表。每个系列精确地重复30次（每个系列中的坐标数）。生成的图表都是正确的。

2）我不需要单独的图表。我希望所有系列都放在一张图表中，并用不同的颜色显示。

我在这里做错了什么？

编辑：

Main：

public class testmain {
    public static void main(String[] args) {
        int threshold = 30;
        List<List<PoolUserLoginsVO>> poolLogins = new ArrayList<>();
        List<PoolUserLoginsVO> userLogins = new ArrayList<>();
        for (int i = 0; i < threshold; ++i) {
            LocalDate localDate = LocalDate.now().minusDays(threshold - i - 1);
            Date date = Date.from(localDate.atStartOfDay(ZoneId.systemDefault()).toInstant());
            PoolUserLoginsVO logins = new PoolUserLoginsVO(i, "pool1", date);
            userLogins.add(logins);
        }
        poolLogins.add(userLogins);

        List<PoolUserLoginsVO> userLogins2 = new ArrayList<>();

        for (int i = 0; i < threshold; ++i) {
            LocalDate localDate = LocalDate.now().minusDays(threshold - i - 1);
            Date date = Date.from(localDate.atStartOfDay(ZoneId.systemDefault()).toInstant());
            PoolUserLoginsVO logins = new PoolUserLoginsVO(1, "pool2", date);
            userLogins2.add(logins);
        }
        poolLogins.add(userLogins2);

        List<PoolUserLoginsVO> userLogins3 = new ArrayList<>();
        for (int i = threshold; i > 0; --i) {
            LocalDate localDate = LocalDate.now().minusDays(threshold - i - 1);
            Date date = Date.from(localDate.atStartOfDay(ZoneId.systemDefault()).toInstant());
            PoolUserLoginsVO logins = new PoolUserLoginsVO(i, "pool3", date);
            userLogins3.add(logins);
        }
        poolLogins.add(userLogins3);

        JRBeanCollectionDataSource vmsJRBean = new JRBeanCollectionDataSource(poolLogins);
        Map<String, Object> parameters = new HashMap<String, Object>();
        parameters.put("poolLogins", poolLogins);

        File file = new File("report.pdf");
        try {
            FileOutputStream fop = new FileOutputStream(file);
            JasperPrint jasperPrint = JasperFillManager.fillReport("test.jasper", parameters, new JREmptyDataSource());
            JasperExportManager.exportReportToPdfStream(jasperPrint, fop);
            fop.flush();
            fop.close();
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JRException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Answer 1