Epublib是一個用於處理epub文件的java類庫,可以對epub文件進行讀寫處理;而且提供了一個閱讀器,可以直接運行(java -jar 方式),並可以打開epub類型的文件進行閱讀;(引用官方網頁的一句話:Epublib is a java library for managing epub files. It’s capable of reading and writing epub files programmatically.)
Epublib 主頁:http://www.siegmann.nl/epublib
Epub viewer的地址:https://github.com/downloads/psiegman/epublib/epublib-viewer-latest.jar
在線API:http://www.siegmann.nl/static/epublib/apidocs/
容易遇到的問題:在epublib的網頁上並沒有提到epublib所依賴的jar,那麼在創建epub文件的時候,就會報如下異常:
- Exception in thread "main" java.lang.NoClassDefFoundError: org/xmlpull/v1/XmlPullParserFactory
- at nl.siegmann.epublib.epub.EpubProcessorSupport.createXmlSerializer(EpubProcessorSupport.java:80)
- at nl.siegmann.epublib.epub.EpubProcessorSupport.createXmlSerializer(EpubProcessorSupport.java:74)
- at nl.siegmann.epublib.epub.NCXDocument.createNCXResource(NCXDocument.java:181)
- at nl.siegmann.epublib.epub.NCXDocument.createNCXResource(NCXDocument.java:177)
- at nl.siegmann.epublib.epub.EpubWriter.initTOCResource(EpubWriter.java:67)
- at nl.siegmann.epublib.epub.EpubWriter.write(EpubWriter.java:51)
- at org.lazyboy.work.document.EPubUtil.createNewFile(EPubUtil.java:124)
- at org.lazyboy.work.document.EPubUtil.main(EPubUtil.java:144)
- Caused by: java.lang.ClassNotFoundException: org.xmlpull.v1.XmlPullParserFactory
- at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
- at java.security.AccessController.doPrivileged(Native Method)
- at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
- at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
- at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
- at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
- ... 8 more
根據提示:org.xmlpull.v1.XmlPullParserFactory類沒有找到,那麼就去找合適的jar吧·····你會發現有很多jar裏包含了這個類,但是如果不巧你添加了jar包之後,雖然沒有了這個異常,但是你會遇到另一個空指針的異常,如下所示:
- Exception in thread "main" java.lang.NullPointerException
- at org.xmlpull.mxp1_serializer.MXSerializer.startDocument(MXSerializer.java:379)
- at nl.siegmann.epublib.epub.PackageDocumentWriter.write(PackageDocumentWriter.java:38)
- at nl.siegmann.epublib.epub.EpubWriter.writePackageDocument(EpubWriter.java:112)
- at nl.siegmann.epublib.epub.EpubWriter.write(EpubWriter.java:53)
- at org.lazyboy.work.document.EPubUtil.createNewFile(EPubUtil.java:124)
- at org.lazyboy.work.document.EPubUtil.main(EPubUtil.java:144)
那就是你加錯jar包了,經過多次試驗後,發現應該加入一個kxml2的jar包,其maven座標如下:
- <dependency>
- <groupId>kxml2</groupId>
- <artifactId>kxml2</artifactId>
- <version>2.2.2</version>
- </dependency>
本人需要做的操作是:讀取一個epub文件,取出需要的chapter,生成一個新的epub文件,或者根據比例對源epub文件進行裁剪;在此過程中遇到了問題,在blog上記錄一下