iReport 笔记(六) 使用子报表(使用JavaBean集合作为数据源)

6 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

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

注: 如需本例源代码, 请留言