如何在使用 iText 生成 PDF 时消除异常
我试图在java spring框架mvc中使用itext渲染pdf。 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;
}
}
这是我的 pdfGenerator 类 公共类 PdfGenerator { 私有静态最终 Logger 日志 = Logger.getLogger(PdfGenerator.class); 私有输出流输出流；
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;
}
但不知怎的
，我得到了一些例外：
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)
任何形式的帮助都是值得赞赏的。 谢谢。
I wast trying to render pdf using itext in java spring framework mvc.
Here's my filter class.
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);
private 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:
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.
Thanks.
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评论（2）
NoSuchMethod 错误表明您正在使用的库版本不匹配。我将首先检查我的库依赖项，并查找某些库是否不需要不同版本的 iText。如果是这样，我会尝试排除一个依赖项或选择支持适当版本的 iText 的库版本。
如果您使用 Maven，请尝试： mvn dependency:tree 并检查是否出现多个 iText
NoSuchMethod error suggest that you have a mismatch of versions of the libraries that you are using. I would start with checking my library dependencies and find if some libraries are not expecting different versions of iText. If so, I would try to exclude one dependency or choose libraries version which support proper versions of iText.
If you are using Maven, try: mvn dependency:tree and check for multiple iText occurence
PDF 生成过程可能会因多种原因而失败。
您必须将 pdf 生成包围在 try/catch 块中，并在 catch 块中进行某种错误处理。我看到处理该问题的两种基本方法：
The process of PDF generation can fail for a wide variety of reasons.
You must surround the pdf generation in a try/catch block and, in the catch block, make some sort of error handling. I see 2 basic way to handle the problem: