子報表
在本例中，我使用子報表將生成如下樣式的報表

6.1 程式部分
第一步，建立與之相關的Bean類，如下所示：

ProvinceBean.java

package lld.test.ireport;

import java.util.ArrayList;

public class ProvinceBean
{
 private String provinceName;
 private ArrayList<CityBean> cities;
 public String getProvinceName()
 {
  return provinceName;
 }
 public void setProvinceName(String provinceName)
 {
  this.provinceName = provinceName;
 }
 public ArrayList<CityBean> getCities()
 {
  return cities;
 }
 public void setCities(ArrayList<CityBean> cities)
 {
  this.cities = cities;
 }
}CityBean.java

package lld.test.ireport;

public class CityBean
{
 private String cityName;

 public String getCityName()
 {
  return cityName;
 }

 public void setCityName(String cityName)
 {
  this.cityName = cityName;
 }
}第二步 建立Servlet類，如下所示

package lld.test.ireport;

import java.io.IOException;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.jasperreports.engine.JRDataSource;
import net.sf.jasperreports.engine.JRExporterParameter;
import net.sf.jasperreports.engine.JasperFillManager;
import net.sf.jasperreports.engine.JasperPrint;
import net.sf.jasperreports.engine.JasperReport;
import net.sf.jasperreports.engine.data.JRBeanCollectionDataSource;
import net.sf.jasperreports.engine.export.JRPdfExporter;
import net.sf.jasperreports.engine.util.JRLoader;

public class ChildReportServlet extends HttpServlet
{

 private static final long serialVersionUID = -1233414483047719876L;

 @Override
 protected void doGet(HttpServletRequest req, HttpServletResponse resp)
   throws ServletException, IOException
 {
  this.doPost(req, resp);
 }

 @Override
 protected void doPost(HttpServletRequest req, HttpServletResponse resp)
   throws ServletException, IOException
 {
  try
  {
   String root_path = this.getServletContext().getRealPath("/");
   root_path = root_path.replace('//', '/');
   String reportFilePath = root_path + "WEB-INF/classes/lld/test/ireport/child_report_jbs_parent.jasper";
   JRDataSource dataSource = this.createDataSource();

   Map<String, String> parameters = new HashMap<String, String>();
   parameters.put("SUBREPORT_DIR", root_path + "WEB-INF/classes/lld/test/ireport/");
   JasperReport report = (JasperReport)JRLoader.loadObject(reportFilePath);
   JasperPrint jasperPrint = JasperFillManager.fillReport(report, parameters, dataSource);

         OutputStream ouputStream = resp.getOutputStream(); 
         resp.setContentType("application/pdf");
         resp.setCharacterEncoding("UTF-8"); 
         resp.setHeader("Content-Disposition", "attachment; filename=/"" 
                 + URLEncoder.encode("PDF報表", "UTF-8") + ".pdf/""); 
              
         // 使用JRPdfExproter匯出器匯出pdf 
         JRPdfExporter exporter = new JRPdfExporter(); 
         exporter.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint);
         exporter.setParameter(JRExporterParameter.OUTPUT_STREAM, ouputStream); 
         exporter.exportReport();
        
        
         ouputStream.close(); 

  }catch(Exception ex)
  {
   ex.printStackTrace();
  }
  
  
 }
 
 private JRDataSource createDataSource()
 {
  //生成測試資料
  ArrayList<ProvinceBean> provinces = new ArrayList<ProvinceBean>();
  
  ProvinceBean province = new ProvinceBean();
  province.setProvinceName("山東");
  
  ArrayList<CityBean> cities = new ArrayList<CityBean>();
  CityBean city = new CityBean();
  city.setCityName("濟南");
  cities.add(city);
  city = new CityBean();
  city.setCityName("青島");
  cities.add(city);
  city = new CityBean();
  city.setCityName("濰坊");
  cities.add(city);
  
  province.setCities(cities);
  provinces.add(province);

  province = new ProvinceBean();
  province.setProvinceName("江蘇");
  
  cities = new ArrayList<CityBean>();
  city = new CityBean();
  city.setCityName("南京");
  cities.add(city);
  city = new CityBean();
  city.setCityName("無錫");
  cities.add(city);
  city = new CityBean();
  city.setCityName("蘇州");
  cities.add(city);
  
  province.setCities(cities);
  provinces.add(province);

  return new JRBeanCollectionDataSource(provinces);
 }

}如果有了以前例子的基礎，這個例子應該不難看懂，需要注意的是下面這4行程式碼，這是新出現的特性：

Map<String, String> parameters = new HashMap<String, String>();
parameters.put("SUBREPORT_DIR", root_path + "WEB-INF/classes/lld/test/ireport/");
JasperReport report = (JasperReport)JRLoader.loadObject(reportFilePath);
JasperPrint jasperPrint = JasperFillManager.fillReport(report, parameters, dataSource);這是因為，在使用子報表時，需要一個SUBREPORT_DIR變數，指示子報表所在的路徑，在下面建立子報表的相關部分會再次進行描述，請注意對比。我在以前的例子中，呼叫JasperFillManager.fillReport()方法時第二個引數均為null，實際上，這個引數可傳遞到jasper report中的Parameters項中。

6.2 建立報表
第一步，建立主報表，如下圖所示

其Connection設定如下圖所示：

其DataSource設定如下圖所示

第二步，建立子報表，可使用工具欄的“SubReport”圖示直接建立，使用預設的名稱，並確定好子報表的位置，利用系統的wizard一步一步設定，注意在第2步設定”Connection/Datasource ”時最好選擇”no connection or datasource”)

    子報表我們使用CityBean做為資料來源，設定方法參考上一步設定dataSource

第三步，在父報表中設定子報表控制元件的屬性，在SubReport面板中設定其“Connection/Data Source Expression”為“new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource($F{cities})”，如下圖所示：

第四步，編譯，將編譯生成的.jasper檔案放置到專案的相應目錄中