java - 从 .jasper 文件获取 JasperPrint 对象

Question

我正在尝试获取 JRPrint 对象，因此代码如下:

import java.io.File;

import net.sf.jasperreports.engine.*;

public class TestClass {
 protected static JasperPrint jasperPrint;
 static JasperReport jasperReport;
 protected static JasperReportsContext jasperReportsContext;

 public static void main(String[] args) {
String fileName = "/home/amira/Desktop/Map/testReports/test/textreport.jasper";
boolean isXMLFile = false;

if (!isXMLFile && fileName.endsWith(".jrxml"))
{
    isXMLFile = true;
}

try
{
  loadReportJrprint(fileName, isXMLFile, DefaultJasperReportsContext.getInstance());
}
catch (JRException e)
{

    System.err.println("Error viewing report design."+ e);

    System.exit(1);
}

try {
  JasperExportManager.exportReportToPdfFile(fileName);
} catch (JRException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
}

 }


protected static void loadReportJrprint(String fileName, boolean isXmlReport, JasperReportsContext jasperReportsContext) throws JRException
{
    if (isXmlReport)
    {
      jasperPrint = JRPrintXmlLoader.loadFromFile(jasperReportsContext, fileName);
      System.out.println(jasperPrint.getName());

    }
    else
    {
      jasperPrint = (JasperPrint)JRLoader.loadObjectFromFile(fileName);
    }

}
}

但我收到此错误:

Exception in thread "main" java.lang.ClassCastException: net.sf.jasperreports.engine.JasperReport cannot be cast to net.sf.jasperreports.engine.JasperPrint
at TestClass.loadReportJrprint(TestClass.java:80)
at TestClass.main(TestClass.java:50)

Answer 1

.jasper 文件仅仅是一个已编译的 .jrxml，因此您检索的是一个 JasperReport 对象，它描述了已编译的模板。要获取描述可供查看或导出的文档的 JasperPrint 对象，您必须首先使用 JasperFillManager.fill 方法之一填充报表。请参阅the javadoc for JasperFillManager .