ITEXT生成PDF报错

在WEBLOGIC下,使用ITEXT生成PDF,一开始都能生成,在运行一段时间后,生成很慢,最后生成的PDF没有中文.
需要LINUX重启后才行.请问有没有解决方法?日志输出见下:java.io.IOException: Stream closed
at java.io.BufferedInputStream.getInIfOpen(BufferedInputStream.java:134)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:256)
at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:307)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
at java.io.InputStreamReader.read(InputStreamReader.java:167)
at org.xhtmlrenderer.css.parser.Lexer.yylex(Lexer.java:1865)
at org.xhtmlrenderer.css.parser.CSSParser.next(CSSParser.java:1798)
at org.xhtmlrenderer.css.parser.CSSParser.la(CSSParser.java:1810)
at org.xhtmlrenderer.css.parser.CSSParser.stylesheet(CSSParser.java:159)
at org.xhtmlrenderer.css.parser.CSSParser.parseStylesheet(CSSParser.java:89)
at org.xhtmlrenderer.context.StylesheetFactoryImpl.parse(StylesheetFactoryImpl.java:78)
at org.xhtmlrenderer.context.StylesheetFactoryImpl.parse(StylesheetFactoryImpl.java:95)
at org.xhtmlrenderer.context.StylesheetFactoryImpl.getStylesheet(StylesheetFactoryImpl.java:174)
at org.xhtmlrenderer.context.StyleReference.readAndParseAll(StyleReference.java:123)
at org.xhtmlrenderer.context.StyleReference.setDocumentContext(StyleReference.java:107)
at org.xhtmlrenderer.pdf.ITextRenderer.setDocument(ITextRenderer.java:178)
at org.xhtmlrenderer.pdf.ITextRenderer.setDocument(ITextRenderer.java:143)
at com.pdf.RendererFilter.doFilter(RendererFilter.java:151)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:57)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:343)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:97)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:101)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:79)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:55)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:36)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:190)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.authentication.preauth.AbstractPreAuthenticatedProcessingFilter.doFilter(AbstractPreAuthenticatedProcessingFilter.java:90)
at org.js.web.security.CustRequestHeaderAuthenticationFilter.doFilter(CustRequestHeaderAuthenticationFilter.java:62)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:106)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:79)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.session.ConcurrentSessionFilter.doFilter(ConcurrentSessionFilter.java:110)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:355)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:150)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:238)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:168)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:57)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:57)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:89)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3650)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2174)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1446)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:173)