这两天公司需要将word文档转为pdf，在网上找了一圈之后也没有一个好的解决方案。看来需要自己实现该功能了。
由于之前解析doc文件时使用poi，想着应该poi这么强大的工具包会支持格式转换，还是仔细看看官方相关文档吧。果然不出所料，只不过poi不直接支持doc到pdf文件的转换，需要用到apache的另外一个工具包——fop。难道想这样来支持自家的项目？或者说由于自家项目有该功能，就不需要集成到POI中了？真是搞不懂。
Apache POI - HWPF and XWPF - Java API to Handle Microsoft Word Files
中的An overview of the code一段有对该功能的明确描述
Source code in the org.apache.poi.hwpf.extractor tree is a wrapper of this to facilitate easy extraction of interesting things (eg the Text), and org.apache.poi.hwpf.converter package contains Word-to-HTML and Word-to-FO converters (* latest can be used to generate PDF from Word files when using with Apache FOP *)
从FOP官网
The Apache™ FOP Project
上可以看到FOP的简介，功能很强大的感觉。
Apache™ FOP (Formatting Objects Processor) is a print formatter driven by XSL formatting objects (XSL-FO) and an output independent formatter. It is a Java application that reads a formatting object (FO) tree and renders the resulting pages to a specified output. Output formats currently supported include PDF, PS, PCL, AFP, XML (area tree representation), Print, AWT and PNG, and to a lesser extent, RTF and TXT. The primary output target is PDF.
既然这种变通的方式可以做，那应该不会有错吧。
不过在使用的时候却走了很多弯路。主要是FOP 2.1版本的
FopFactory.newInstance
方法需要一个
fopConf
文件的参数，但哪里来的
fopConf
文件呢？官网给出的例子也没有说这个
fopCOnf
文件是什么格式，做什么用的，感觉真是有点迷惑。
官网示例参见
Apache™ FOP: Embedding
最终在下载的fop-2.1-bin.zip包包含的例子中找到了官方给出的范例，如下所示
具体类路径fop-2.1\examples\embedding\java\embedding\ExampleFO2PDF.java
重点是下面这句代码。这代码，真是坑啊！弄了半天，fopConf还是不知道干嘛用的
private final FopFactory fopFactory = FopFactory.newInstance(new File(“.”).toURI());
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
/* $Id: ExampleFO2PDF.java 1356646 2012-07-03 09:46:41Z mehdi $ */
package
embedding
;
// Java
import
java.io.BufferedOutputStream
;
import
java.io.File
;
import
java.io.FileOutputStream
;
import
java.io.IOException
;
import
java.io.OutputStream
;
import
javax.xml.transform.Result
;
import
javax.xml.transform.Source
;
import
javax.xml.transform.Transformer
;
import
javax.xml.transform.TransformerFactory
;
import
javax.xml.transform.sax.SAXResult
;
import
javax.xml.transform.stream.StreamSource
;
import
org.apache.fop.apps.FOPException
;
import
org.apache.fop.apps.FOUserAgent
;
import
org.apache.fop.apps.Fop
;
import
org.apache.fop.apps.FopFactory
;
import
org.apache.fop.apps.FormattingResults
;
import
org.apache.fop.apps.MimeConstants
;
import
org.apache.fop.apps.PageSequenceResults
;
* This class demonstrates the conversion of an FO file to PDF using FOP.
public
class
ExampleFO2PDF
{
// configure fopFactory as desired
private
final
FopFactory
fopFactory
=
FopFactory
.
newInstance
(
new
File
(
"."
).
toURI
());
* Converts an FO file to a PDF file using FOP
* @param fo the FO file
* @param pdf the target PDF file
* @throws IOException In case of an I/O problem
* @throws FOPException In case of a FOP problem
public
void
convertFO2PDF
(
File
fo
,
File
pdf
)
throws
IOException
,
FOPException
{
OutputStream
out
=
null
;
try
{
FOUserAgent
foUserAgent
=
fopFactory
.
newFOUserAgent
();
// configure foUserAgent as desired
// Setup output stream. Note: Using BufferedOutputStream
// for performance reasons (helpful with FileOutputStreams).
out
=
new
FileOutputStream
(
pdf
);
out
=
new
BufferedOutputStream
(
out
);
// Construct fop with desired output format
Fop
fop
=
fopFactory
.
newFop
(
MimeConstants
.
MIME_PDF
,
foUserAgent
,
out
);
// Setup JAXP using identity transformer
TransformerFactory
factory
=
TransformerFactory
.
newInstance
();
Transformer
transformer
=
factory
.
newTransformer
();
// identity transformer
// Setup input stream
Source
src
=
new
StreamSource
(
fo
);
// Resulting SAX events (the generated FO) must be piped through to FOP
Result
res
=
new
SAXResult
(
fop
.
getDefaultHandler
());
// Start XSLT transformation and FOP processing
transformer
.
transform
(
src
,
res
);
// Result processing
FormattingResults
foResults
=
fop
.
getResults
();
java
.
util
.
List
pageSequences
=
foResults
.
getPageSequences
();
for
(
java
.
util
.
Iterator
it
=
pageSequences
.
iterator
();
it
.
hasNext
();)
{
PageSequenceResults
pageSequenceResults
=
(
PageSequenceResults
)
it
.
next
();
System
.
out
.
println
(
"PageSequence "
+
(
String
.
valueOf
(
pageSequenceResults
.
getID
()).
length
()
>
0
?
pageSequenceResults
.
getID
()
:
"<no id>"
)
+
" generated "
+
pageSequenceResults
.
getPageCount
()
+
" pages."
);
System
.
out
.
println
(
"Generated "
+
foResults
.
getPageCount
()
+
" pages in total."
);
}
catch
(
Exception
e
)
{
e
.
printStackTrace
(
System
.
err
);
System
.
exit
(-
1
);
}
finally
{
out
.
close
();
* Main method.
* @param args command-line arguments
public
static
void
main
(
String
[]
args
)
{
try
{
System
.
out
.
println
(
"FOP ExampleFO2PDF\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
fofile
=
new
File
(
baseDir
,
"xml/fo/helloworld.fo"
);
//File fofile = new File(baseDir, "../fo/pagination/franklin_2pageseqs.fo");
File
pdffile
=
new
File
(
outDir
,
"ResultFO2PDF.pdf"
);
System
.
out
.
println
(
"Input: XSL-FO ("
+
fofile
+
")"
);
System
.
out
.
println
(
"Output: PDF ("
+
pdffile
+
")"
);
System
.
out
.
println
();
System
.
out
.
println
(
"Transforming..."
);
ExampleFO2PDF
app
=
new
ExampleFO2PDF
();
app
.
convertFO2PDF
(
fofile
,
pdffile
);
System
.
out
.
println
(
"Success!"
);
}
catch
(
Exception
e
)
{
e
.
printStackTrace
(
System
.
err
);
System
.
exit
(-
1
);
最终代码如下：
