Ireport使用子报表(使用JavaBean集合作为数据源)

子报表
在本例中，我使用子报表将生成如下样式的报表

 

6.1 程序部分
第一步，创建与之相关的Bean类，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 创建Servlet类，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报表", "UTF-8") + ".pdf/""); 
              
         // 使用JRPdfExproter导出器导出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()
 {
  //生成测试数据
  ArrayList<ProvinceBean> provinces = new ArrayList<ProvinceBean>();
  
  ProvinceBean province = new ProvinceBean();
  province.setProvinceName("山东");
  
  ArrayList<CityBean> cities = new ArrayList<CityBean>();
  CityBean city = new CityBean();
  city.setCityName("济南");
  cities.add(city);
  city = new CityBean();
  city.setCityName("青岛");
  cities.add(city);
  city = new CityBean();
  city.setCityName("潍坊");
  cities.add(city);
  
  province.setCities(cities);
  provinces.add(province);

  province = new ProvinceBean();
  province.setProvinceName("江苏");
  
  cities = new ArrayList<CityBean>();
  city = new CityBean();
  city.setCityName("南京");
  cities.add(city);
  city = new CityBean();
  city.setCityName("无锡");
  cities.add(city);
  city = new CityBean();
  city.setCityName("苏州");
  cities.add(city);
  
  province.setCities(cities);
  provinces.add(province);

  return new JRBeanCollectionDataSource(provinces);
 }

}如果有了以前例子的基础，这个例子应该不难看懂，需要注意的是下面这4行代码，这是新出现的特性：

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);这是因为，在使用子报表时，需要一个SUBREPORT_DIR变量，指示子报表所在的路径，在下面创建子报表的相关部分会再次进行描述，请注意对比。我在以前的例子中，调用JasperFillManager.fillReport()方法时第二个参数均为null，实际上，这个参数可传递到jasper report中的Parameters项中。

6.2 创建报表
第一步，创建主报表，如下图所示

    

                                    

 

其Connection设置如下图所示：

    

                                  

其DataSource设置如下图所示

 

 

第二步，创建子报表，可使用工具栏的“SubReport”图标直接创建，使用默认的名称，并确定好子报表的位置，利用系统的wizard一步一步设置，注意在第2步设置”Connection/Datasource ”时最好选择”no connection or datasource”)

    子报表我们使用CityBean做为数据源，设置方法参考上一步设置dataSource

第三步，在父报表中设置子报表控件的属性，在SubReport面板中设置其“Connection/Data Source Expression”为“new net.sf.jasperreports.engine.data.JRBeanCollectionDataSource($F{cities})”，如下图所示：

 

第四步，编译，将编译生成的.jasper文件放置到项目的相应目录中