如何使用iText生成PDF时摆脱异常

Question

I wast trying to render pdf using itext in java spring framework mvc. 我没有尝试在Java Spring Framework MVC中使用itext渲染pdf。 Here's my filter class. 这是我的过滤器类。

 public class PdfFilter implements Filter, ApplicationContextAware {

@SuppressWarnings({ "UnusedDeclaration" })
private static final Logger log = Logger.getLogger(PdfFilter.class);
protected ApplicationContext applicationContext;

public void init(FilterConfig config) {
    /* do nothing */
}

public void destroy() {
    /* do nothing */
}

public void doFilter(ServletRequest req, ServletResponse resp,
        FilterChain filterChain) throws IOException, ServletException {

    HttpServletRequest request = (HttpServletRequest) req;
    HttpServletResponse response = (HttpServletResponse) resp;

    // Check to see if this filter should apply.
    if (!"pdf".equals(request.getParameter("reportViewType"))) {
        filterChain.doFilter(request, response);
        return;
    }

    // Capture the content for this request
    ContentCaptureServletResponse capContent = new ContentCaptureServletResponse(
            response);
    filterChain.doFilter(request, capContent);

    response.setContentType("application/pdf; charset=UTF-8");
    response.setHeader("Content-disposition",
            "attachment; filename=\"report.pdf\"");
    response.addHeader("Cache-Control", "-1");

    try {
        // Get the html content
        String htmlContent = capContent.getHtlmContent();

        PdfGenerator pdfGenerator = new PdfGenerator(
                response.getOutputStream());

        pdfGenerator.renderPdf(htmlContent, request, response);

    } catch (Exception e) {
        throw new ServletException(e);
    }
}

public void setApplicationContext(ApplicationContext applicationContext) {
    this.applicationContext = applicationContext;
}
}

and here's my pdfGenerator class public class PdfGenerator { private static final Logger log = Logger.getLogger(PdfGenerator.class); 这是我的pdfGenerator类public class PdfGenerator {private static final Logger log = Logger.getLogger（PdfGenerator.class）; private OutputStream outputStream; 私有OutputStream outputStream;

public PdfGenerator(OutputStream os) {
    this.outputStream = os;
}

public void renderPdf(String htmlContent, HttpServletRequest request,
        HttpServletResponse response) throws Exception {
    log.debug("renderPdf");

    htmlContent = cleanUpHtml(htmlContent);
    htmlContent = addHeadBodyTag(htmlContent);

    htmlContent = addCss(htmlContent);

    log.debug("convertToXhtml-e:");
    OutputStream xhtmlOs = new ByteArrayOutputStream();

    Tidy tidy = new Tidy();
    tidy.setXHTML(true);
    tidy.setCharEncoding(Configuration.UTF8);
    tidy.parse(new ByteArrayInputStream(htmlContent.getBytes()), xhtmlOs);

    xhtmlOs.flush();
    xhtmlOs.close();
    log.debug(xhtmlOs.toString());
    StringReader contentReader = new StringReader(xhtmlOs.toString());

    InputSource source = new InputSource(contentReader);

    DocumentBuilder documentBuilder = DocumentBuilderFactory.newInstance()
            .newDocumentBuilder();
    // documentBuilder.setEntityResolver(new MyResolver(request));
    documentBuilder.setEntityResolver(new NoOpEntityResolver());

    Document xhtmlContent = documentBuilder.parse(source);

    ITextRenderer renderer = new ITextRenderer();
    renderer.setDocument(xhtmlContent, null);
    renderer.layout();

    renderer.createPDF(outputStream);

    outputStream.close();

}

private String cleanUpHtml(String data) {
    log.debug("cleanUpHtml-e:");

    data = HtmlUtils.removeAllTags(data, "<script", "</script>", null);
    data = HtmlUtils.replaceAll(data, "<a .*?>|</a>", "");
    // data = HtmlUtils.replaceAll(data, "<img .*?>|</img>", "");
    data = HtmlUtils.replaceAll(data, "<link .*?>", "");
    // remove hidden field
    data = HtmlUtils.replaceAll(data, "<input.*?type=['\"]hidden['\"].*?>",
            "");
    // remove pagination from lister
    data = HtmlUtils
            .replaceAll(
                    data,
                    "(<div style=\"top: .*?px; position: absolute;\" id=\"pager\" class=\"pager\".*?</div>)",
                    "");

    return data;
}

private String addHeadBodyTag(String data) {
    // data = "<html><head></head><body>" + data + "</body></html>";
    return data;
}

private String addCss(String data) {
    log.debug("addCss-e:");

    return data;
}

private String addHead(String data, HttpServletRequest request) {
    log.debug("addHeader-e:");
    StringBuilder sb = new StringBuilder(500);
    String header = sb.toString();
    data = HtmlUtils.replaceAll(data, "(<body.*?>)", "$1" + header);

    return data;

}

private String addFooter(String data) {
    log.debug("addFooter-e:");

    String footer = "iit lone gunmen 2.0";

    data = HtmlUtils.replaceAll(data, "(<body.*?>)", "$1" + footer);
    return data;
}

} }

but somehow Im getting some exception: 但以某种方式我得到一些例外：

 Jan 26, 2012 5:43:08 AM org.apache.catalina.core.StandardWrapperValve invoke
 SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/govForms]       threw exception [Filter execution threw an exception] with root cause
    java.lang.NoSuchMethodError: com.lowagie.text.Rectangle.getHeight()F
at org.xhtmlrenderer.pdf.ITextRenderer.writePDF(ITextRenderer.java:339)
at org.xhtmlrenderer.pdf.ITextRenderer.createPDF(ITextRenderer.java:315)
at org.xhtmlrenderer.pdf.ITextRenderer.createPDF(ITextRenderer.java:246)
at bd.gov.forms.web.pdf.PdfGenerator.renderPdf(PdfGenerator.java:64)
at bd.gov.forms.web.pdf.PdfFilter.doFilter(PdfFilter.java:54)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:119)
at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:55)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Any kind of help is appreciated. 任何帮助都将受到赞赏。 Thanks. 谢谢。

Answer 1

NoSuchMethod error suggest that you have a mismatch of versions of the libraries that you are using. NoSuchMethod错误提示您使用的库版本不匹配。 I would start with checking my library dependencies and find if some libraries are not expecting different versions of iText. 我将从检查我的库依赖关系开始，然后确定某些库是否期望使用不同版本的iText。 If so, I would try to exclude one dependency or choose libraries version which support proper versions of iText. 如果是这样，我将尝试排除一种依赖关系或选择支持iText正确版本的库版本。

If you are using Maven, try: mvn dependency:tree and check for multiple iText occurence 如果您使用的是Maven，请尝试：mvndependency：tree并检查是否出现多个iText

Answer 2

The process of PDF generation can fail for a wide variety of reasons. PDF生成过程可能由于多种原因而失败。 You must surround the pdf generation in a try/catch block and, in the catch block, make some sort of error handling. 您必须在try / catch块中包围pdf生成，并在catch块中进行某种错误处理。 I see 2 basic way to handle the problem: 我看到了2种解决问题的基本方法：

Deploy your app with a default pdf document: in the catched generation exception serve the content of the default pdf, which would contain a generic warning phrase of failed generation 使用默认的pdf文档部署您的应用程序：在捕获的生成异常中提供默认pdf的内容，该内容将包含生成失败的通用警告短语
The pdf generator return the result in a stream of bytes (and not directly in the response output stream) and only if return correctly, you set up the response headers to serve the generated pdf and copy the byte returned in the response output stream; pdf生成器以字节流（而不是直接在响应输出流中）返回结果，只有正确返回后，才设置响应标头以服务于生成的pdf，并复制在响应输出流中返回的字节； in the catched generation exception you set up the response to serve a html page describing the error or you can redirect to a standard error page. 在捕获的生成异常中，您可以将响应设置为提供一个描述错误的html页面，也可以重定向到标准错误页面。

如何使用iText生成PDF时摆脱异常

问题描述

2 个解决方案

解决方案1
0 2012-01-26 09:17:22

解决方案2
-1 2012-01-27 11:26:14

如何使用iText生成PDF时摆脱异常

问题描述

2 个解决方案

解决方案1 0 2012-01-26 09:17:22

解决方案2 -1 2012-01-27 11:26:14

解决方案1
0 2012-01-26 09:17:22

解决方案2
-1 2012-01-27 11:26:14