JasperReports 报表组Groups

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2023-03-14

1 JasperReports 报表组Groups 介绍

JasperReports 中的报表组有助于以逻辑方式组织报告中的数据。一个报表组代表数据源中一系列连续的记录，它们有一些共同点，例如某个报表字段的值。报告组由 <group> 元素定义。一个报告可以有任意数量的组。声明后，可以在整个报告中提及团体。

报表组具有三个要素：

组表达式：这表示必须更改以启动新数据组的数据。
组的头部分：帮助将标签放置在分组数据的开头。
组的页脚部分：帮助在分组数据的末尾放置标签。

在报表填充时迭代数据源期间，如果组表达式的值发生变化，则会发生组断裂，并且相应的 <groupFooter> 和 <groupHeader> 部分将插入到生成的文档中。

报表组机制不对数据源提供的数据进行任何排序。仅当数据源中的记录已根据报表中使用的组表达式进行排序时，数据分组才能按预期工作。

2 JasperReports 报表组Groups 属性

<group> 元素包含允许我们控制分组数据的布局方式的属性。属性总结在下表中：

属性	描述
name	这是必须的属性。它按名称引用报表表达式中的组。它遵循我们为报表参数、字段和报告变量提到的相同命名约定。当您想要引用特定报表组时，它可以用于其他 JRXML 属性。
isStartNewColumn	设置为true 时，每个数据组将从新列开始。默认值为false。
isStartNewPage	设置为true 时，每个数据组将在新页面上开始。默认值为false。
isResetPageNumber	设置为true 时，每次新组开始时都会重置报告页码。默认值为false。
isReprintHeaderOnEachPage	当设置为true 时，组标题将在每一页上重新打印。默认值为false。
minHeightToStartNewPage	定义列底部所需的最小垂直空间量，以便将组标题放置在当前列上。金额以报表单位指定。
footerPosition	呈现页面上组页脚的位置，以及它与跟随它的报表部分相关的行为。它的值可以是：Normal、StackAtBottom、ForceAtBottom和CollateAtBottom。默认值为Normal。
keepTogether	当设置为true 时，防止组在第一次尝试时分裂。

3 JasperReports 报表组Groups 示例

让我们将一个组 ( CountryGroup )添加到现有报告模板 (JasperReports 模板设计章节 )。统计每个国家/地区的出现次数，并将计数显示为组页脚。在组头中，每条记录的计数都带有前缀。

项目结构如下：

pom.xml文件

<dependencies>
        <!-- https://mvnrepository.com/artifact/net.sf.jasperreports/jasperreports -->
        <dependency>
            <groupId>net.sf.jasperreports</groupId>
            <artifactId>jasperreports</artifactId>
            <version>6.17.0</version>
        </dependency>
        <dependency>
            <groupId>org.codehaus.groovy</groupId>
            <artifactId>groovy-all</artifactId>
            <version>2.4.7</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.17</version>
        </dependency>
    </dependencies>

DataBean实体类：

package cn.xnip;

public class DataBean {
   private String name;
   private String country;

   public String getName() {
      return name;
   }

   public void setName(String name) {
      this.name = name;
   }

   public String getCountry() {
      return country;
   }

   public void setCountry(String country) {
      this.country = country;
   }
}

DataBeanList类：

package cn.xnip;

import java.util.ArrayList;

public class DataBeanList {
   public ArrayList<DataBean> getDataBeanList() {
      ArrayList<DataBean> dataBeanList = new ArrayList<DataBean>();

      dataBeanList.add(produce("Manisha", "India"));
      dataBeanList.add(produce("Dennis Ritchie", "USA"));
      dataBeanList.add(produce("V.Anand", "India"));
      dataBeanList.add(produce("Shrinath", "California"));

      return dataBeanList;
   }

   /**
    * This method returns a DataBean object,
    * with name and country set in it.
    */
   private DataBean produce(String name, String country) {
      DataBean dataBean = new DataBean();
      dataBean.setName(name);
      dataBean.setCountry(country);

      return dataBean;
   }
}

jasper_report_template.jrxml模板文件：

<?xml version = "1.0"?>
<!DOCTYPE jasperReport PUBLIC
   "//JasperReports//DTD Report Design//EN"
   "http://jasperreports.sourceforge.net/dtds/jasperreport.dtd">

<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 = "jasper_report_template" pageWidth = "595"
   pageHeight = "842" columnWidth = "515"
   leftMargin = "40" rightMargin = "40" topMargin = "50" bottomMargin = "50">

   <parameter name = "ReportTitle" class = "java.lang.String"/>
   <parameter name = "Author" class = "java.lang.String"/>

   <queryString>
      <![CDATA[]]>
   </queryString>

   <field name = "country" class = "java.lang.String">
      <fieldDescription><![CDATA[country]]></fieldDescription>
   </field>

   <field name = "name" class = "java.lang.String">
      <fieldDescription><![CDATA[name]]></fieldDescription>
   </field>
   
   <sortField name = "country" order = "Descending"/>
   <sortField name = "name"/>
   
   <variable name = "CountryNumber" class = "java.lang.Integer"
      incrementType = "Group" incrementGroup = "CountryGroup"
      calculation = "Count">
      <variableExpression><![CDATA[Boolean.TRUE]]></variableExpression>
   </variable>
   
   <group name = "CountryGroup" minHeightToStartNewPage = "60">
      <groupExpression><![CDATA[$F{country}]]></groupExpression>
      
      <groupHeader>
         <band height = "20">
            
            <textField evaluationTime = "Group" evaluationGroup = "CountryGroup"
               bookmarkLevel = "1">
               <reportElement mode = "Opaque" x = "0" y = "5" width = "515"
                  height = "15" backcolor = "#C0C0C0"/>
               
               <box leftPadding = "10">
                  <bottomPen lineWidth = "1.0"/>
               </box>
               <textElement/>
               
               <textFieldExpression class = "java.lang.String">
                  <![CDATA["  " + String.valueOf($V{CountryNumber}) + ". "
                  + String.valueOf($F{country})]]>
               </textFieldExpression>
               
               <anchorNameExpression>
                  <![CDATA[String.valueOf($F{country})]]>
               </anchorNameExpression>
            </textField>
         
         </band>
      </groupHeader>
      
      <groupFooter>
         <band height = "20">
            
            <staticText>
               <reportElement x = "400" y = "1" width = "60" height = "15"/>
               <textElement textAlignment = "Right"/>
               <text><![CDATA[Count :]]></text>
            </staticText>
            
            <textField>
               <reportElement x = "460" y = "1" width = "30" height = "15"/>
               <textElement textAlignment = "Right"/>
               
               <textFieldExpression class = "java.lang.Integer">
                  <![CDATA[$V{CountryGroup_COUNT}]]>
               </textFieldExpression>
            </textField>
         
         </band>
      </groupFooter>
   
   </group>
   
   <title>
      <band height = "70">
         
         <line>
            <reportElement x = "0" y = "0" width = "515" height = "1"/>
         </line>
         
         <textField isBlankWhenNull = "true" bookmarkLevel = "1">
            <reportElement x = "0" y = "10" width = "515" height = "30"/>
            
            <textElement textAlignment = "Center">
               <font size = "22"/>
            </textElement>
            
            <textFieldExpression class = "java.lang.String">
               <![CDATA[$P{ReportTitle}]]>
            </textFieldExpression>
            
            <anchorNameExpression>
               <![CDATA["Title"]]>
            </anchorNameExpression>
         </textField>
            
         <textField isBlankWhenNull = "true">
            <reportElement  x = "0" y = "40" width = "515" height = "20"/>
            
            <textElement textAlignment = "Center">
               <font size = "10"/>
            </textElement>
            
            <textFieldExpression class = "java.lang.String">
               <![CDATA[$P{Author}]]>
            </textFieldExpression>
         </textField>
      
      </band>
   </title>

   <columnHeader>
      <band height = "23">
         
         <staticText>
            <reportElement mode = "Opaque" x = "0" y = "3" width = "535" height = "15"
               backcolor = "#70A9A9" />
            
            <box>
               <bottomPen lineWidth = "1.0" lineColor = "#CCCCCC" />
            </box>
            
            <textElement />
				
            <text>
               <![CDATA[]]>
            </text>
         </staticText>
         
         <staticText>
            <reportElement x = "414" y = "3" width = "121" height = "15" />
            
            <textElement textAlignment = "Center" verticalAlignment = "Middle">
               <font isBold = "true" />
            </textElement>
            
            <text><![CDATA[Country]]></text>
         </staticText>
         
         <staticText>
            <reportElement x = "0" y = "3" width = "136" height = "15" />
            
            <textElement textAlignment = "Center" verticalAlignment = "Middle">
               <font isBold = "true" />
            </textElement>
            
            <text><![CDATA[Name]]></text>
         </staticText>
      
      </band>
   </columnHeader>

   <detail>
      <band height = "16">
         
         <staticText>
            <reportElement mode = "Opaque" x = "0" y = "0" width = "535" height = "14"
               backcolor = "#E5ECF9" />
            
            <box>
               <bottomPen lineWidth = "0.25" lineColor = "#CCCCCC" />
            </box>
				
            <textElement />
				
            <text>
               <![CDATA[]]>  
            </text>
         </staticText>
         
         <textField>
            <reportElement x = "414" y = "0" width = "121" height = "15" />
            
            <textElement textAlignment = "Center" verticalAlignment = "Middle">
               <font size = "9" />
            </textElement>
            
            <textFieldExpression class = "java.lang.String">
               <![CDATA[$F{country}]]>
            </textFieldExpression>
         </textField>
         
         <textField>
            <reportElement x = "0" y = "0" width = "136" height = "15" />
            <textElement textAlignment = "Center" verticalAlignment = "Middle" />
            
            <textFieldExpression class = "java.lang.String">
               <![CDATA[$F{name}]]>
            </textFieldExpression>
         </textField>
      
      </band>
   </detail>
	
</jasperReport>

先编译报表文件：

package cn.xnip;

import net.sf.jasperreports.engine.*;
import net.sf.jasperreports.view.JasperViewer;

public class JasperReportFill {

   public static void main(String[] args) {
      String filePath = "D:/idea_codes/jasper_reports/jasper_report_template.jrxml";
      try {
         JasperCompileManager.compileReportToFile(filePath,"d:/jasper_report_template.jasper");
         System.out.println("编译成功");
      } catch (JRException e) {
         e.printStackTrace();
      }
   }
}

编译后在D:/盘根目录下生成jasper_report_template.jasper文件，然后再填充数据：

package cn.xnip;

import net.sf.jasperreports.engine.*;
import net.sf.jasperreports.engine.data.JRBeanCollectionDataSource;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

public class JasperReportFill {

   public static void main(String[] args) {
         String sourceFileName = "d:/jasper_report_template.jasper";

         DataBeanList DataBeanList = new DataBeanList();
         ArrayList<DataBean> dataList = DataBeanList.getDataBeanList();

         JRBeanCollectionDataSource beanColDataSource =
                 new JRBeanCollectionDataSource(dataList);

         Map parameters = new HashMap();
         /**
          * Passing ReportTitle and Author as parameters
          */
         parameters.put("ReportTitle", "List of Contacts");
         parameters.put("Author", "Prepared By Manisha");

         try {
            JasperFillManager.fillReportToFile(
                    sourceFileName, parameters, beanColDataSource);
         } catch (JRException e) {
            e.printStackTrace();
         }
      }
}

填充数据完毕后，在D:/盘根目录下生成jasper_report_template.jrprint文件，最后使用预览程序预览：

package cn.xnip;

import net.sf.jasperreports.engine.*;
import net.sf.jasperreports.view.JasperViewer;

public class JasperReportFill {

   public static void main(String[] args) {
      String filePath = "D:/jasper_report_template.jrprint";
      try {
         JasperViewer.viewReport(filePath,false);
      } catch (JRException e) {
         e.printStackTrace();
      }
   }
}

最后输出结果如下：

从效果我们看到，每个国家都被分组，每个国家的出现次数显示在每个组的页脚。