運行java代碼時自動生成空白碧玉報告的錯誤

Question

我試圖用Eclipse Neon JAVA EE IDE使用Jaspersoft studio 6.4.0運行空白的Jasperreport（空白A4.Jrxml）。每次運行這段代碼時，我都會被要求添加一個jasper jar依賴文件。於是我將Jasper庫和Jasper jar文件下載到我的Java程序（JasperClass.java）中並保存在lib文件夾中。但我仍然收到錯誤添加jar文件。我研究了棧流以前的解決方案，但仍然無法解決它。請幫助我。

JAR庫lib文件夾：https://imgur.com/Nj1FOGk

錯誤：

Oct 11, 2017 1:01:28 PM net.sf.jasperreports.extensions.DefaultExtensionsRegistry loadRegistries 
WARNING: Extension resource jar:file:/C:/repo/JasperTest/lib/jasperreports-javaflow-6.4.0.jar!/jasperreports_extension.properties was found to be a duplicate of jar:file:/C:/repo/JasperTest/lib/jasperreports-6.4.0.jar!/jasperreports_extension.properties in classloader sun.misc.Launcher$AppClassLoader@73d16e93 
Exception in thread "main" java.lang.NoClassDefFoundError: com/lowagie/text/DocumentException 
    at net.sf.jasperreports.engine.JasperExportManager.exportToPdfFile(JasperExportManager.java:150) 
    at net.sf.jasperreports.engine.JasperExportManager.exportReportToPdfFile(JasperExportManager.java:503) 
    at JasperPackage.JasperClass.main(JasperClass.java:45) 
Caused by: java.lang.ClassNotFoundException: com.lowagie.text.DocumentException 
    at java.net.URLClassLoader.findClass(Unknown Source) 
    at java.lang.ClassLoader.loadClass(Unknown Source) 
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) 
    at java.lang.ClassLoader.loadClass(Unknown Source) 
    ... 3 more 

的Java Class.Java

import java.io.File; 
    import java.io.IOException; 
    import java.util.HashMap; 
    import java.util.Map; 

    import net.sf.jasperreports.engine.JRDataSource; 
    import net.sf.jasperreports.engine.JREmptyDataSource; 
    import net.sf.jasperreports.engine.JRException; 
    import net.sf.jasperreports.engine.JasperCompileManager; 
    import net.sf.jasperreports.engine.JasperExportManager; 
    import net.sf.jasperreports.engine.JasperFillManager; 
    import net.sf.jasperreports.engine.JasperPrint; 
    import net.sf.jasperreports.engine.JasperReport; 
    public class JasperClass { 

     public static void main(String[] args) throws JRException, IOException { 

      // Compile jrxml file. 
      JasperReport jasperReport = JasperCompileManager 
        .compileReport("C:/repo/JasperTest/Blank_A4.jrxml"); 

      // Parameters for report 
      Map<String, Object> parameters = new HashMap<String, Object>(); 

      // DataSource 
      // This is simple example, no database. 
      // then using empty datasource. 
      JRDataSource dataSource = new JREmptyDataSource(); 

      JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, 
        parameters, dataSource); 


      // Make sure the output directory exists. 
      File outDir = new File("C:/repo/JasperTest"); 
      outDir.mkdirs(); 

      // Export to PDF. 
      JasperExportManager.exportReportToPdfFile(jasperPrint, 
        "C:/repo/JasperTest/Blank.pdf"); 

      System.out.println("Done!"); 
     } 
    } 

空白A4.jrxml

<?xml version="1.0" encoding="UTF-8"?> 
<!-- Created with Jaspersoft Studio version 6.4.0.final using JasperReports Library version 6.4.1 --> 
<jasperReport xmlns="http://jasperreports.sourceforge.net/jasperreports" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://jasperreports.sourceforge.net/jasperreports http://jasperreports.sourceforge.net/xsd/jasperreport.xsd" name="Blank_A4" pageWidth="595" pageHeight="842" columnWidth="555" leftMargin="20" rightMargin="20" topMargin="20" bottomMargin="20" uuid="1b2e21df-4dba-46a0-8e2e-1bed8b81853e"> 
    <property name="com.jaspersoft.studio.data.defaultdataadapter" value="One Empty Record"/> 
    <queryString> 
     <![CDATA[]]> 
    </queryString> 
    <background> 
     <band splitType="Stretch"/> 
    </background> 
    <title> 
     <band height="79" splitType="Stretch"/> 
    </title> 
    <pageHeader> 
     <band height="35" splitType="Stretch"/> 
    </pageHeader> 
    <columnHeader> 
     <band height="61" splitType="Stretch"/> 
    </columnHeader> 
    <detail> 
     <band height="125" splitType="Stretch"/> 
    </detail> 
    <columnFooter> 
     <band height="45" splitType="Stretch"/> 
    </columnFooter> 
    <pageFooter> 
     <band height="54" splitType="Stretch"/> 
    </pageFooter> 
    <summary> 
     <band height="42" splitType="Stretch"/> 
    </summary> 
</jasperReport> 

Answer 1

基於E xception在堆棧跟蹤你似乎有重複的JAR文件在你的倉庫lib目錄

JasperReports的-javaflow-6.4.0.jar JasperReports的-6.4.0.jar

都是這些JAR文件的必要嗎？

Answer 2

謝謝你的幫助。我的問題解決了。

1. 我從lib文件夾中刪除了Javaflow6.4.0 jar而不是Jasperreport 6.4.0 jar。 爲異常

   二零一七年十月一十一日下午1時01分28秒net.sf.jasperreports.extensions.DefaultExtensionsRegistry loadRegistries 警告：擴展資源的jar：文件：/ C：/回購/ JasperTest/lib目錄/ JasperReports的-javaflow發現-6.4.0.jar！/jasperreports_extension.properties與classloader sun.misc中的jar：file：/ C：/repo/JasperTest/lib/jasperreports-6.4.0.jar！/jasperreports_extension.properties相同。啓動$ AppClassLoader @螺紋73d16e93 異常 「主要」 java.lang.NoClassDefFoundError：COM/lowagie /文本/ DocumentExceptio

2. 後來我得到了如下的異常。然後，我將Itext 2.1.7 jar和itext pdf 5.5.0 jar一起添加到lib文件中。這工作。 Exception in thread "main" java.lang.NoClassDefFoundError: com/lowagie/text/DocumentException at net.sf.jasperreports.engine.JasperExportManager.exportToPdfF‌​ile(JasperExportMana‌​ger.java:150)

再次感謝您。