我在jasper报告中有一个查询，由用户提供的输入生成的结果集之一可能是以下所述的数据：
memberId stockNo refineryCode constantSerialNo serialNo
45 1 IAR A- 98729
45 1 IAR A- 98730
45 1 IAR A- 98731
45 1 IAR A- 98733
45 1 IAR A- 98734
45 1 IAR A- 98736
45 1 IAR A- 98737
45 1 IAR A- 98738
45 1 IAR A- 98739
如果serialNo是连续的，我想在一行上显示这些基准。因此，如果我想在报告中显示以上数据，则必须按照以下说明的方式进行显示：
memberId stockNo refineryCode constantSerialNo serialNo
45 1 IAR A- 98729 - 98731
45 1 IAR A- 98733 - 98734
45 1 IAR A- 98736 - 98739
我知道可能存在一些使用sql上的游标或以Java之类的OOP语言使用ORM并发送到jasper报告的解决方案。但是，出于好奇，我想问一下是否存在使用iReport的Expressions或Groups的动态解决方案，或者是我现在想到的任何其他事情，这可以使我的生活更轻松。
最佳答案
假设serialNo是某种数值而不是字符串，这是一种实现方法。
如上所示，sql查询结果的数据集必须按serialNo进行排序。
用以下组表达式创建一个Report Group：$V{GroupCount} == new BigDecimal(0) ? $F{serialNo}:$F{serialNo}.subtract($V{GroupCount})。每当serialNo序列中存在间隔时，这将创建一个新组。
创建一个变量GroupCount，该变量对当前组中连续的serialNo值进行计数。此变量用于跟踪下一个预期的serialNo值是什么。
创建一个变量StartRange，该变量将保存给定范围的连续serialNo值的起始值。该值应在新组开始时重置，并具有以下值：$V{GroupCount}.intValue() == 1 ? $F{ID}:$V{StartRange}。
将Evaluation Time字段的serialNo值设置为ReportGroup。在其中输入以下值：$V{StartRange}+" - " + $F{serialNo}。
将Print When Expression区域的Detail更改为以下内容：new Boolean($V{GroupCount}.intValue() == 1)。
我已经在下面发布了完整的jrxml代码。
<?xml version="1.0" encoding="utf-8"?>
<!-- Created with iReport - A designer for JasperReports -->
<!DOCTYPE jasperReport PUBLIC "//JasperReports//DTD Report Design//EN"
"http://jasperreports.sourceforge.net/dtds/jasperreport.dtd">
<jasperReport name="Group_By_Consecutive" columnCount="1" printOrder="Vertical" orientation="Portrait" pageWidth="595" pageHeight="842" columnWidth="535" columnSpacing="0" leftMargin="30" rightMargin="30" topMargin="20" bottomMargin="20" whenNoDataType="NoPages" isTitleNewPage="false" isSummaryNewPage="false">
<property name="ireport.scriptlethandling" value="0" />
<property name="ireport.encoding" value="UTF-8" />
<import value="java.util.*" />
<import value="net.sf.jasperreports.engine.*" />
<import value="net.sf.jasperreports.engine.data.*" />
<queryString>
<![CDATA[select 1 as id, 'Name 1' as name from dual union all
select 2 as id, 'Name 2' as name from dual union all
select 3 as id, 'Name 3' as name from dual union all
select 4 as id, 'Name 4' as name from dual union all
select 6 as id, 'Name 6' as name from dual union all
select 7 as id, 'Name 7' as name from dual union all
select 8 as id, 'Name 8' as name from dual union all
select 9 as id, 'Name 9' as name from dual union all
select 10 as id, 'Name 10' as name from dual union all
select 11 as id, 'Name 11' as name from dual union all
select 14 as id, 'Name 14' as name from dual union all
select 15 as id, 'Name 15' as name from dual union all
select 16 as id, 'Name 16' as name from dual union all
select 17 as id, 'Name 17' as name from dual union all
select 23 as id, 'Name 23' as name from dual union all
select 24 as id, 'Name 24' as name from dual union all
select 25 as id, 'Name 25' as name from dual union all
select 26 as id, 'Name 26' as name from dual union all
select 27 as id, 'Name 27' as name from dual union all
select 28 as id, 'Name 28' as name from dual]]>
</queryString>
<field name="ID" class="java.math.BigDecimal" />
<field name="NAME" class="java.lang.String" />
<variable name="GroupCount" class="java.math.BigDecimal" resetType="Group" resetGroup="Consecutive" calculation="Count">
<variableExpression>
<![CDATA[$F{ID}]]>
</variableExpression>
<initialValueExpression>
<![CDATA[new BigDecimal(0)]]>
</initialValueExpression>
</variable>
<variable name="StartRange" class="java.math.BigDecimal" resetType="Report" calculation="Nothing">
<variableExpression>
<![CDATA[$V{GroupCount}.intValue() == 1 ? $F{ID}:$V{StartRange}]]>
</variableExpression>
</variable>
<group name="Consecutive">
<groupExpression>
<![CDATA[$V{GroupCount} == new BigDecimal(0) ? $F{ID}:$F{ID}.subtract($V{GroupCount})]]>
</groupExpression>
<groupHeader>
<band height="0" isSplitAllowed="true"></band>
</groupHeader>
<groupFooter>
<band height="0" isSplitAllowed="true"></band>
</groupFooter>
</group>
<background>
<band height="0" isSplitAllowed="true"></band>
</background>
<title>
<band height="0" isSplitAllowed="true"></band>
</title>
<pageHeader>
<band height="0" isSplitAllowed="true"></band>
</pageHeader>
<columnHeader>
<band height="18" isSplitAllowed="true">
<staticText>
<reportElement x="0" y="0" width="200" height="18" key="staticText-1" />
<box></box>
<textElement>
<font />
</textElement>
<text>
<![CDATA[serialNo]]>
</text>
</staticText>
<staticText>
<reportElement x="200" y="0" width="100" height="18" key="staticText-3" />
<box></box>
<textElement>
<font />
</textElement>
<text>
<![CDATA[Name]]>
</text>
</staticText>
<staticText>
<reportElement x="300" y="0" width="100" height="18" key="staticText-4" />
<box></box>
<textElement>
<font />
</textElement>
<text>
<![CDATA[MetaData(Ignore)]]>
</text>
</staticText>
</band>
</columnHeader>
<detail>
<band height="18" isSplitAllowed="true">
<printWhenExpression>
<![CDATA[new Boolean($V{GroupCount}.intValue() == 1)]]>
</printWhenExpression>
<textField isStretchWithOverflow="false" isBlankWhenNull="false" evaluationTime="Now" hyperlinkType="None" hyperlinkTarget="Self">
<reportElement x="200" y="0" width="100" height="18" key="textField" />
<box></box>
<textElement>
<font />
</textElement>
<textFieldExpression class="java.lang.String">
<![CDATA[$F{NAME}]]>
</textFieldExpression>
</textField>
<textField isStretchWithOverflow="false" pattern="##0.00" isBlankWhenNull="false" evaluationTime="Group" evaluationGroup="Consecutive" hyperlinkType="None" hyperlinkTarget="Self">
<reportElement x="0" y="0" width="200" height="18" key="textField" />
<box></box>
<textElement>
<font />
</textElement>
<textFieldExpression class="java.lang.String">
<![CDATA[$V{StartRange}+" - " + $F{ID}]]>
</textFieldExpression>
</textField>
<textField isStretchWithOverflow="false" pattern="##0.00" isBlankWhenNull="false" evaluationTime="Now" hyperlinkType="None" hyperlinkTarget="Self">
<reportElement x="300" y="0" width="100" height="18" key="textField" />
<box></box>
<textElement>
<font />
</textElement>
<textFieldExpression class="java.math.BigDecimal">
<![CDATA[$V{GroupCount}]]>
</textFieldExpression>
</textField>
</band>
</detail>
<columnFooter>
<band height="0" isSplitAllowed="true"></band>
</columnFooter>
<pageFooter>
<band height="0" isSplitAllowed="true"></band>
</pageFooter>
<summary>
<band height="0" isSplitAllowed="true"></band>
</summary>
</jasperReport>
关于java - 在JasperReports(iReport)中对数据集上的连续编号进行分组，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/10518334/