jaspersoft 父报表向子报表传值循环

jsaper子报表Subreport(父子报表互相传值)有很多人都说Jasperreports不适合中国式复杂报表，实际上运用好父子报表可以解决大部分问题了。例如下面的表。每个学生的学科数目不固定，且每个学生后有相当于小计的平均分。有点复杂度的报表，可以使用子报表解决。 

 1.1 设计报表模板1.1.1 新建主模板DemoReport6_main.jrxml，创建Paramters ：title(java.lang.String)、date(java.lang.String)、SUBREPORT_DIR（java.lang.String），创建Fields ：stuNo(java.lang.Integer)、stuName(java.lang.String)、subjectList（java.util.List） 

 1.1.2 设计模板表头如下，注意宽度： 

 1.1.3 新建子模板DemoReport6_sub.jrxml，只保留DetailBand(Height设置为20)，并设置模板的宽500，高20，且四周Margin都为0 

 1.1.4 转到DemoReport6_main主模板，将Subreport组件拖入到Detail中，跳出Subreport界面 

  

 1.1.5 将stuNo和stuName拖入到Detail中 

 1.1.6 转到DemoReport6_sub子模板，新建Fields：subjectName（String）、teacherName(String)、score(java.lang.Double).拖入到Detail中，注意宽度和主模板保持一致 

 1.1.7 新建Variables,命名为averageScore 

 1.1.8 转回DemoReport6_mian主模块，新建Variables,命名为getAverageScore 

 拖入到Detail Band中，设置好字体样式 

 点击 $V{getAverageScore} 显示Properties,设置Appearance中Position Type选中为Fix Relation To Bottom（同样将“平均分”如此设置） 

 设置TextField的Evaluation Time 选中为Band 

 1.1.11 点击Subreport 显示Properties,在Subreport中设置Exception为$P{SUBREPORT_DIR}+"DemoReport6_sub.jasper"，Data Source Expression为newnet.sf.jasperreports.engine.data.JRBeanCollectionDataSource($F{subjectList}) 

  

 点击 Edit Return Values 

 保存主模板，子模板，放到项目中的jrxml中。1.2 编写Servlet注入数据源 1.2.1 新建 Student类和Subject类 package com.jasper.bean;import java.util.ArrayList;import java.util.List;public class Student {//注意和模板中数据类型保持一致private Integer stuNo;private String stuName;private List subjectList = new ArrayList();// get、set方法省略}package com.jasper.bean;public class Subject {private String subjectName;private String teacherName;private Double score;// get、set方法省略}1.2.2 新建JasperServlet6,doGet内容如下： protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {Map parameters = new HashMap(16);//组装list数据源Subject sub1 = new Subject("语文","张老师",80.0);Subject sub2 = new Subject("数学","王老师",90.0);Subject sub3 = new Subject("物理","孙老师",46.0);Subject sub4 = new Subject("政治","李老师",50.0);List list = new ArrayList();Student stu1 = new Student();stu1.setStuNo(101);stu1.setStuName("小明");List sublist1 = new ArrayList();sublist1.add(sub1);sublist1.add(sub2);stu1.setSubjectList(sublist1);Student stu2 = new Student();stu2.setStuNo(102);stu2.setStuName("小雨");List sublist2 = new ArrayList();sublist2.add(sub2);sublist2.add(sub3);sublist2.add(sub4);stu2.setSubjectList(sublist2);Student stu3 = new Student();stu3.setStuNo(103);stu3.setStuName("小东");List sublist3 = new ArrayList();sublist3.add(sub4);sublist3.add(sub3);stu3.setSubjectList(sublist3);list.add(stu1);list.add(stu2);list.add(stu3);String mainjrxmlPath = request.getServletContext().getRealPath("/")+"/jrxml/DemoReport6_main.jrxml";String subjrxmlPath = request.getServletContext().getRealPath("/")+"/jrxml/DemoReport6_sub.jrxml";//由jrxml文件编译后生产jasper文件的路径String mainjasperPath = request.getServletContext().getRealPath("/")+"/jasper/DemoReport6_main.jasper";String subjasperPath = request.getServletContext().getRealPath("/")+"/jasper/DemoReport6_sub.jasper";try {//编译jrxml生产jasper文件JasperCompileManager.compileReportToFile(mainjrxmlPath, mainjasperPath);JasperCompileManager.compileReportToFile(subjrxmlPath, subjasperPath);parameters.put("title", "学生成绩表");parameters.put("date", new SimpleDateFormat("yyyy-MM-dd").format(new Date()));String SUBREPORT_DIR = request.getServletContext().getRealPath("/")+"/jasper/";parameters.put("SUBREPORT_DIR",SUBREPORT_DIR);JasperPrint jasperPrint = JasperFillManager.fillReport(mainjasperPath, parameters, new JRBeanCollectionDataSource(list));//生成html文件（位置：D:/HTML/student.html）JasperExportManager.exportReportToHtmlFile(jasperPrint, "D:/HTML/student.html");} catch (JRException e) {e.printStackTrace();}} 1.3 启动tomcat，访问servlet,查看html文件