我有一个 appengine java 项目，其中包括在某些时候创建 pdf。pdf 文档有我试图包含的特殊字体：
BaseFont bf = BaseFont.createFont("resources/AlexBrush-Regular.ttf", "", BaseFont.EMBEDDED);
代码在本地运行完美，但部署时我得到 NoClassDefFoundError （下面的堆栈跟踪）。有没有人成功在 appengine 上向 iText 添加自定义字体？我正在使用 iTextg-5.4.4
java.lang.NoClassDefFoundError: java.nio.MappedByteBuffer is a restricted class. Please see the Google App Engine developer's guide for more details.
at com.google.apphosting.runtime.security.shared.stub.java.nio.channels.FileChannel_.map(FileChannel.java)
at com.itextpdf.text.io.MappedChannelRandomAccessSource.open(MappedChannelRandomAccessSource.java:104)
at com.itextpdf.text.io.FileChannelRandomAccessSource.<init>(FileChannelRandomAccessSource.java:71)
at com.itextpdf.text.io.RandomAccessSourceFactory.createBestSource(RandomAccessSourceFactory.java:212)
at com.itextpdf.text.io.RandomAccessSourceFactory.createBestSource(RandomAccessSourceFactory.java:193)
at com.itextpdf.text.pdf.RandomAccessFileOrArray.<init>(RandomAccessFileOrArray.java:147)
at com.itextpdf.text.pdf.TrueTypeFont.process(TrueTypeFont.java:625)
at com.itextpdf.text.pdf.TrueTypeFont.<init>(TrueTypeFont.java:369)
at com.itextpdf.text.pdf.BaseFont.createFont(BaseFont.java:705)
at com.itextpdf.text.pdf.BaseFont.createFont(BaseFont.java:621)
at com.itextpdf.text.pdf.BaseFont.createFont(BaseFont.java:456)
at ccfb.server.servlets.PaypalCheckoutServlet.doPost(PaypalCheckoutServlet.java:156)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
at com.google.apphosting.utils.servlet.ParseBlobUploadFilter.doFilter(ParseBlobUploadFilter.java:125)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.runtime.jetty.SaveSessionFilter.doFilter(SaveSessionFilter.java:35)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.JdbcMySqlConnectionCleanupFilter.doFilter(JdbcMySqlConnectionCleanupFilter.java:60)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
at com.google.apphosting.runtime.jetty.AppVersionHandlerMap.handle(AppVersionHandlerMap.java:266)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
at com.google.apphosting.runtime.jetty.RpcRequestParser.parseAvailable(RpcRequestParser.java:76)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at com.google.apphosting.runtime.jetty.JettyServletEngineAdapter.serviceRequest(JettyServletEngineAdapter.java:146)
at com.google.apphosting.runtime.JavaRuntime$RequestRunnable.run(JavaRuntime.java:446)
at com.google.tracing.TraceContext$TraceContextRunnable.runInContext(TraceContext.java:435)
at com.google.tracing.TraceContext$TraceContextRunnable$1.run(TraceContext.java:442)
at com.google.tracing.CurrentContext.runInContext(CurrentContext.java:186)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContextNoUnref(TraceContext.java:306)
at com.google.tracing.TraceContext$AbstractTraceContextCallback.runInInheritedContext(TraceContext.java:298)
at com.google.tracing.TraceContext$TraceContextRunnable.run(TraceContext.java:439)
at com.google.apphosting.runtime.ThreadGroupPool$PoolEntry.run(ThreadGroupPool.java:251)
at java.lang.Thread.run(Thread.java:724)