Author: Holyfair
E-Mail: Holyfair@sina.com
一. 序 在一些运用中,我们通常会把一些文本和配置信息转换成XML文件进行传输,修改,保存.特别是具有一定模板性质的文档用XML文件来实现其管理就显得相当的方便了.提供对于XML文件的操作的java API很多,诸于DOM,JDOM,Castor,SAX,XMLReader,XPath,XSLT等等. 具体的这些API的用法这里就不多提了. 当使用这些接口实现XML的操作后,对于有些文档而言最终必须呈现给用户看的还是我们通常所熟悉的WORD和PDF文档.我们这里就来看一下从一个XML文件到RTF和PDF文件转换的实现.
二. 从XML到PDF 对于一个具有一定模板性质的XML文件,我们可以用FOP API来实现其到PDF的转换.
FOP需要fop.jar. 我们可以到http://xml.apache.org/fop/ 上获取和了解其用法.
以一个一般复杂的XML文件为例:
要转换XML文档 test.xml 如下:
<FeatureSRS title="SRS">
<introduction>
<objective>objective here</objective>
<scope>scope here</scope>
<responsibilities>responsibilities here</responsibilities>
<references>reference here</references>
<DAA>
<term>
term here
</term>
<definition>
definition here
</definition>
</DAA>
</introduction>
<generalDescription>
<featureName>
<summary>summary here</summary>
<breakdown>breakdown here</breakdown>
</featureName>
<requirement>
<content>
content here.
</content>
</requirement>
<requirement>
<content>
content2 here.
</content>
</requirement>
<featureInteractions>featureInteractions here</featureInteractions>
</generalDescription>
<strResources>
<strResource>
<estring>
estring here
</estring>
<resourceid>
resourceid here
</resourceid>
<rqmt>
rqmt here.
</rqmt>
</strResource>
</strResources>
</FeatureSRS>
对于这样一个XML文档,我们要将其转化成PDF格式必须建立一个XSL-FO文件,来定义对各element和value格
式的转换.
我们建立XSL-FO文件 test.xsl 如下:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.1" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format" exclude-result-prefixes="fo">
<xsl:output method="xml" version="1.0" omit-xml-declaration="no" indent="yes"/>
<!-- ========================= -->
<!-- root element: projectteam -->
<!-- ========================= -->
<xsl:template match="FeatureSRS">
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
<fo:layout-master-set>
<fo:simple-page-master master-name="simpleA4" page-height="29.7cm" page-width="21cm" margin-top="2cm" margin-bottom="2cm" margin-left="2cm" margin-right="2cm">
<fo:region-body/>
</fo:simple-page-master>
</fo:layout-master-set>
<fo:page-sequence master-reference="simpleA4">
<fo:flow flow-name="xsl-region-body">
<fo:block font-size="20pt" font-weight="bold" space-after="5mm" text-align="center">Cardiac Feature SRS
</fo:block>
<fo:block font-size="10pt">
<xsl:apply-templates/>
</fo:block>
</fo:flow>
</fo:page-sequence>
</fo:root>
</xsl:template>
<!-- ========================= -->
<!-- child element: member -->
<!-- ========================= -->
<xsl:template name="introduction" match="introduction">
<fo:block font-size="18pt" font-weight="bold" space-after="5mm">1. Intruction</fo:block>
<fo:block font-size="14pt" font-weight="bold" space-after="5mm" margin-left="5mm">1.1 Objective</fo:block>
<fo:block font-size="10pt" font-weight="normal" space-after="5mm" margin-left="7mm">
<xsl:value-of select="objective"/>
</fo:block>
<fo:block font-size="14pt" font-weight="bold" space-after="5mm" margin-left="5mm">1.2 Scope</fo:block>
<fo:block font-size="10pt" font-weight="normal" space-after="5mm" margin-left="7mm">
<xsl:value-of select="scope"/>
</fo:block>
<fo:block font-size="14pt" font-weight="bold" space-after="5mm" margin-left="5mm">1.3. Responsibilities</fo:block>
<fo:block font-size="10pt" font-weight="normal" space-after="5mm" margin-left="7mm">
<xsl:value-of select="responsibilities"/>
</fo:block>
<fo:block font-size="14pt" font-weight="bold" space-after="5mm" margin-left="5mm">1.4. References</fo:block>
<fo:block font-size="10pt" font-weight="normal" space-after="5mm" margin-left="7mm">
<xsl:value-of select="references"/>
</fo:block>
<fo:block font-size="14pt" font-weight="bold" space-after="5mm" margin-left="5mm">1.5. Definitions, Acronyms, and Abbreviations</fo:block>
<fo:block font-size="10pt" font-weight="bold" space-after="5mm" margin-left="5mm">
<fo:table table-layout="fixed" border="2cm" background-color="#fff2d9" >
<fo:table-column column-width="4cm"/>
<fo:table-column column-width="6cm"/>
<fo:table-body>
<fo:table-row border="2">
<fo:table-cell>
<fo:block>
<xsl:text>Term</xsl:text>
</fo:block>
</fo:table-cell>
<fo:table-cell>
<fo:block>
<xsl:text>Definition</xsl:text>
</fo:block>
</fo:table-cell>
</fo:table-row>
<xsl:for-each select="DAA">
<fo:table-row border="2">
<fo:table-cell>
<fo:block>
<xsl:value-of select="term"/>
</fo:block>
</fo:table-cell>
<fo:table-cell>
<fo:block>
<xsl:value-of select="definition"/>
</fo:block>
</fo:table-cell>
</fo:table-row>
</xsl:for-each>
</fo:table-body>
</fo:table>
</fo:block>
</xsl:template>
<xsl:template name="generalDescription" match="generalDescription">
<fo:block font-size="18pt" font-weight="bold" space-after="5mm">2. General Description</fo:block>
<fo:block font-size="14pt" font-weight="bold" space-after="5mm" margin-left="5mm">2.1. Feature Name</fo:block>
<fo:block font-size="14pt" font-weight="bold" space-after="5mm" margin-left="7mm">2.1.1. Feature Summary</fo:block>
<fo:block font-size="10pt" font-weight="normal" space-after="5mm" margin-left="9mm">
<xsl:value-of select="featureName/summary"/>
</fo:block>
<fo:block font-size="14pt" font-weight="bold" space-after="5mm" margin-left="7mm">2.1.2. Feature Breakdown</fo:block>
<fo:block font-size="10pt" font-weight="normal" space-after="5mm" margin-left="9mm">
<xsl:value-of select="featureName/breakdown"/>
</fo:block>
<fo:block font-size="14pt" font-weight="bold" space-after="5mm" margin-left="5mm">2.2. Feature Requirements</fo:block>
<fo:block font-size="10pt" font-weight="normal" space-after="5mm" margin-left="7mm">
<xsl:for-each select="requirement">
<xsl:value-of select="content"/>
</xsl:for-each>
</fo:block>
<fo:block font-size="14pt" font-weight="bold" space-after="5mm" margin-left="5mm">2.3. Feature Interactions</fo:block>
<fo:block font-size="10pt" font-weight="normal" space-after="5mm" margin-left="7mm">
<xsl:value-of select="featureInteractions"/>
</fo:block>
</xsl:template>
<xsl:template name="strResources" match="strResources">
<fo:block font-size="18pt" font-weight="bold" space-after="5mm">3. String Resources </fo:block>
<fo:block font-size="10pt" font-weight="bold" space-after="5mm" margin-left="5mm">
<fo:table table-layout="fixed" border="2cm" background-color="#fff2d9" >
<fo:table-column column-width="4cm"/>
<fo:table-column column-width="10cm"/>
<fo:table-column column-width="4cm"/>
<fo:table-body>
<fo:table-row border="2">
<fo:table-cell>
<fo:block>
<xsl:text>English String</xsl:text>
</fo:block>
</fo:table-cell>
<fo:table-cell>
<fo:block>
<xsl:text>Resource ID</xsl:text>
</fo:block>
</fo:table-cell>
<fo:table-cell>
<fo:block>
<xsl:text>Rqmt</xsl:text>
</fo:block>
</fo:table-cell>
</fo:table-row>
<xsl:for-each select="strResource">
<fo:table-row border="2">
<fo:table-cell>
<fo:block>
<xsl:value-of select="estring"/>
</fo:block>
</fo:table-cell>
<fo:table-cell>
<fo:block>
<xsl:value-of select="resourceid"/>
</fo:block>
</fo:table-cell>
<fo:table-cell>
<fo:block>
<xsl:value-of select="rqmt"/>
</fo:block>
</fo:table-cell>
</fo:table-row>
</xsl:for-each>
</fo:table-body>
</fo:table>
</fo:block>
</xsl:template>
</xsl:stylesheet>
其具体的XSL-FO文件格式的语法可以参照一些其他资料.
建立好了此文件之后,我们就可以用FOP提供的一些接口方便的进行转换了.
FOP提供了XML->FO,XML->PDF,FO-PDF,OBJ->FO,OBJ->PDF的转换接口.
我们这里以XML->PDF的为例,其余的可以参照FOP包里相应的DEMO.
public class ExampleXML2PDF {
public void convertXML2PDF(File xml, File xslt, File pdf)
throws IOException, FOPException, TransformerException {
Driver driver = new Driver();
Logger logger = new ConsoleLogger(ConsoleLogger.LEVEL_INFO);
driver.setLogger(logger);
MessageHandler.setScreenLogger(logger);
//Setup Renderer (output format)
driver.setRenderer(Driver.RENDER_PDF);
//Setup output
OutputStream out = new java.io.FileOutputStream(pdf);
try {
driver.setOutputStream(out);
//Setup XSLT
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer(new StreamSource(xslt));
//Setup input for XSLT transformation
Source src = new StreamSource(xml);
//Resulting SAX events (the generated FO) must be piped through to FOP
Result res = new SAXResult(driver.getContentHandler());
//Start XSLT transformation and FOP processing
transformer.transform(src, res);
} finally {
out.close();
}
}
public static void main(String[] args) {
try {
System.out.println("FOP ExampleXML2PDF\n");
System.out.println("Preparing...");
//Setup directories
File baseDir = new File(".");
File outDir = new File(baseDir, "out");
outDir.mkdirs();
//Setup input and output files
File xmlfile = new File(baseDir, "test.xml");
File xsltfile = new File(baseDir, "test.xsl");
File pdffile = new File(outDir, "test.pdf");
System.out.println("Input: XML (" + xmlfile + ")");
System.out.println("Stylesheet: " + xsltfile);
System.out.println("Output: PDF (" + pdffile + ")");
System.out.println();
System.out.println("Transforming...");
ExampleXML2PDF app = new ExampleXML2PDF();
app.convertXML2PDF(xmlfile, xsltfile, pdffile);
System.out.println("Success!");
} catch (Exception e) {
System.err.println(ExceptionUtil.printStackTrace(e));
System.exit(-1);
}
}
}
这样我们就很轻易地实现了XML文档到PDF文档的转换.
如果这些用在webservice的servlet中,想从xml文件直接生成pdf传输给浏览者而并不生成的pdf文件,我们可以如
下实现:
public class FOPServlet extends HttpServlet {
public static final String FO_REQUEST_PARAM = "fo";
public static final String XML_REQUEST_PARAM = "xml";
public static final String XSL_REQUEST_PARAM = "xsl";
public void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException {
try {
String xmlParam =getServletContext().getRealPath("WEB-INF/doc/xml/test.xml");
String xslParam =getServletContext().getRealPath("WEB-INF/doc/xsl/test.xsl");
if ((xmlParam != null) && (xslParam != null)) {
XSLTInputHandler input =
new XSLTInputHandler(new File(xmlParam),
new File(xslParam));
renderXML(input, response);
} else {
PrintWriter out = response.getWriter();
out.println("<html><head><title>Error</title></head>\n"+
"<body><h1>FopServlet Error</h1><h3>No 'fo' "+
"request param given.</body></html>");
}
} catch (ServletException ex) {
throw ex;
}
catch (Exception ex) {
throw new ServletException(ex);
}
}
public void renderXML(XSLTInputHandler input,
HttpServletResponse response) throws ServletException {
try {
ByteArrayOutputStream out = new ByteArrayOutputStream();
response.setContentType("application/pdf");
Driver driver = new Driver();
driver.setRenderer(Driver.RENDER_PDF);
driver.setOutputStream(out);
driver.render(input.getParser(), input.getInputSource());
byte[] content = out.toByteArray();
response.setContentLength(content.length);
response.getOutputStream().write(content);
response.getOutputStream().flush();
} catch (Exception ex) {
throw new ServletException(ex);
}
}
}
三. XML to RTF xml到rtf的转换稍微有一些麻烦,我们没有直接从XML到RTF的API, 我们将要用的JFor API还没有整合到FOP
中去. JFor API可以实现 从 FO文件到RTF文件的转换, 它也提供了consle接口.
我们可以从 www.jfor.org 上获取jfor相关信息.
我们从XML文件到RTF文件的转换可以分为两步:
1. 用FOP将 xml 转换成 fo
2. 用JFor将 fo 转换成RTF
3.1 用FOP将 xml 转换成 fo
这一步我们可以很轻易的沿用上面所述的方法,如下实现xml到fo 的转换,依然会用到上面所用的xml文件
和xsl-fo文件.
OutputStream foOut = new FileOutputStream(fofile);
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer(new StreamSource(
xsltfile));
Source src = new StreamSource(xmlfile);
Result res = new StreamResult(foOut);
transformer.transform(src, res);
foOut.close();
3.2 用JFor将 fo 转换成RTF
仅以Serlvet需求的实现为例:
InputStream foInput = new FileInputStream(fofile);
InputSource inputSource = new InputSource(foInput);
ByteArrayOutputStream out = new ByteArrayOutputStream();
Writer output = new OutputStreamWriter(out);
response.setContentType("application/msword");
new Converter(inputSource,output,Converter.createConverterOption ());
output.flush();
byte[] content = out.toByteArray();
System.out.println(out.toString());
response.setContentLength(content.length);
response.getOutputStream().write(content);
response.getOutputStream().flush();
foInput.close();
output.close();
out.close();
这样我们就成功地将xml转化成了RTF格式的文件.
本文仅简述了大体的实现过程,具体的细节可参照各技术点的详细自述.
