由于工作需要，今天简单的看了一下Java生成PDF的相关资料。综合看下来，除了使用报表平台和OOo的附带工具，目前使用较为普遍的有两个途径：iText和Apache的FOP。从实际出发，我们分别看看两者处理带有中文的PDF的具体用法吧。
[iText] ( link)
iText我想大概不少人都有所耳闻，JasperReports默认的PDF支持就来自这个软件包，它处理速度快，支持很多PDF"高级"特性，如：Annotations、AcroForms、数字签名、加密等，支持对已有PDF的处理，通过iTextAsian.jar和iTextAsianCmaps.jar，它对中文的支持也不错。缺点是较为依赖Java代码，需要学习不少的专有API，当输入/输出格式有变化时，需要修改代码（除非手工写一些wrapper），不够灵活。目前的版本是2.1.3。具体代码：
Formatter.java
1
import
java.io.FileOutputStream;
2
3 import com.lowagie.text.Document;
4 import com.lowagie.text.Font;
5 import com.lowagie.text.PageSize;
6 import com.lowagie.text.Paragraph;
7 import com.lowagie.text.pdf.BaseFont;
8 import com.lowagie.text.pdf.PdfWriter;
9
10 public class Formatter {
11
12 public static void main(String[] args) throws Exception {
13 Document document = new Document(PageSize.A4);
14 try {
15 System.out.print( " Generating PDF![]()
"
);
16 PdfWriter.getInstance(document, new FileOutputStream( " test.pdf " ));
17 document.open();
18 // iText自带的中文字体
19 BaseFont bf1 = BaseFont.createFont( " STSong-Light " , " UniGB-UCS2-H " , BaseFont.NOT_EMBEDDED);
20 // 自定义字体
21 BaseFont bf2 = BaseFont.createFont( " wqy-zenhei.ttf " , BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
22 Font font = new Font(bf2, 12 , Font.NORMAL);
23 Paragraph p = new Paragraph( " 测试abc中文123 " , font);
24 document.add(p);
25 System.out.println( " Done. " );
26 } finally {
27 document.close();
28 }
29 }
30
31 }
2
3 import com.lowagie.text.Document;
4 import com.lowagie.text.Font;
5 import com.lowagie.text.PageSize;
6 import com.lowagie.text.Paragraph;
7 import com.lowagie.text.pdf.BaseFont;
8 import com.lowagie.text.pdf.PdfWriter;
9
10 public class Formatter {
11
12 public static void main(String[] args) throws Exception {
13 Document document = new Document(PageSize.A4);
14 try {
15 System.out.print( " Generating PDF
16 PdfWriter.getInstance(document, new FileOutputStream( " test.pdf " ));
17 document.open();
18 // iText自带的中文字体
19 BaseFont bf1 = BaseFont.createFont( " STSong-Light " , " UniGB-UCS2-H " , BaseFont.NOT_EMBEDDED);
20 // 自定义字体
21 BaseFont bf2 = BaseFont.createFont( " wqy-zenhei.ttf " , BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
22 Font font = new Font(bf2, 12 , Font.NORMAL);
23 Paragraph p = new Paragraph( " 测试abc中文123 " , font);
24 document.add(p);
25 System.out.println( " Done. " );
26 } finally {
27 document.close();
28 }
29 }
30
31 }
效果：
中文支持有默认的STSong-Light等字体，但为了优化输出效果，这里使用了文泉驿正黑字体。如果不指定中文字体，默认情况下中文字符不会显示。
[FOP] ( link)
FOP出自Apache，在各大Java网站、论坛出现相对较低，我也是从DocBook这条线摸进来的，DocBook主要提供了一个现成的、符合一般技术书籍要求的数据结构，而展现效果（如PDF），则是通过预定义好的XSL-FO来实现的。XSL-FO是W3C的标准，正式的名称是XSL，是XSL相关的三大组件/语言中的一个，另外两个是XSLT和XPath。Apache的FOP是处理FO的众多proecessor之一，相比iText，支持的输出格式更多，对W3C相关标准支持度高，格式定义可以完全脱离具体的Java代码，十分灵活，且控制力很强。缺点是大数据量时性能较差，默认中文支持不好。目前的版本是0.95。具体代码：
test.xml
1
<?
xml version="1.0" encoding="UTF-8"
?>
2 < source >
3 < title >
4 FOP Sample
5 </ title >
6 < paragraph >
7 测试abc中文123
8 </ paragraph >
9 </ source >
2 < source >
3 < title >
4 FOP Sample
5 </ title >
6 < paragraph >
7 测试abc中文123
8 </ paragraph >
9 </ source >
test.xsl
1
<?
xml version="1.0" encoding="UTF-8"
?>
2 < xsl:transform version ="1.0"
3 xmlns:xsl ="http://www.w3.org/1999/XSL/Transform"
4 xmlns:fo ="http://www.w3.org/1999/XSL/Format" >
5
6 < xsl:template match ="/" >
7 < fo:root >
8 < fo:layout-master-set >
9 < fo:simple-page-master master-name ="A4-portrait"
10 page-height ="29.7cm" page-width ="21.0cm" margin ="2cm" >
11 < fo:region-body />
12 </ fo:simple-page-master >
13 </ fo:layout-master-set >
14 < fo:page-sequence master-reference ="A4-portrait" >
15 < fo:flow flow-name ="xsl-region-body" >
16 < fo:block font-family ="WenQuanYi Zen Hei" font-size ="24pt" >
17 < xsl:value-of select ="source/title" />
18 </ fo:block >
19 < fo:block font-family ="WenQuanYi Zen Hei" text-indent ="1cm" >
20 < xsl:value-of select ="source/paragraph" />
21 </ fo:block >
22 </ fo:flow >
23 </ fo:page-sequence >
24 </ fo:root >
25 </ xsl:template >
26
27 </ xsl:transform >
2 < xsl:transform version ="1.0"
3 xmlns:xsl ="http://www.w3.org/1999/XSL/Transform"
4 xmlns:fo ="http://www.w3.org/1999/XSL/Format" >
5
6 < xsl:template match ="/" >
7 < fo:root >
8 < fo:layout-master-set >
9 < fo:simple-page-master master-name ="A4-portrait"
10 page-height ="29.7cm" page-width ="21.0cm" margin ="2cm" >
11 < fo:region-body />
12 </ fo:simple-page-master >
13 </ fo:layout-master-set >
14 < fo:page-sequence master-reference ="A4-portrait" >
15 < fo:flow flow-name ="xsl-region-body" >
16 < fo:block font-family ="WenQuanYi Zen Hei" font-size ="24pt" >
17 < xsl:value-of select ="source/title" />
18 </ fo:block >
19 < fo:block font-family ="WenQuanYi Zen Hei" text-indent ="1cm" >
20 < xsl:value-of select ="source/paragraph" />
21 </ fo:block >
22 </ fo:flow >
23 </ fo:page-sequence >
24 </ fo:root >
25 </ xsl:template >
26
27 </ xsl:transform >
fop-config.xml
1
<?
xml version="1.0"
?>
2 < fop version ="1.0" >
3 < base > . </ base >
4 < source-resolution > 72 </ source-resolution >
5 < target-resolution > 72 </ target-resolution >
6 < default-page-settings height ="29.7cm" width ="21.0cm" />
7 < renderers >
8 < renderer mime ="application/pdf" >
9 < filterList >
10 < value > flate </ value >
11 </ filterList >
12 < fonts >
13 < directory > . </ directory >
14 < auto-detect />
15 </ fonts >
16 </ renderer >
17 </ renderers >
18 </ fop >
2 < fop version ="1.0" >
3 < base > . </ base >
4 < source-resolution > 72 </ source-resolution >
5 < target-resolution > 72 </ target-resolution >
6 < default-page-settings height ="29.7cm" width ="21.0cm" />
7 < renderers >
8 < renderer mime ="application/pdf" >
9 < filterList >
10 < value > flate </ value >
11 </ filterList >
12 < fonts >
13 < directory > . </ directory >
14 < auto-detect />
15 </ fonts >
16 </ renderer >
17 </ renderers >
18 </ fop >
Formatter.java
1
import
java.io.File;
2 import java.io.FileOutputStream;
3 import java.io.OutputStream;
4
5 import javax.xml.transform.Result;
6 import javax.xml.transform.Source;
7 import javax.xml.transform.Transformer;
8 import javax.xml.transform.TransformerFactory;
9 import javax.xml.transform.sax.SAXResult;
10 import javax.xml.transform.stream.StreamSource;
11
12 import org.apache.fop.apps.FOUserAgent;
13 import org.apache.fop.apps.Fop;
14 import org.apache.fop.apps.FopFactory;
15 import org.apache.fop.apps.MimeConstants;
16
17 public class Formatter {
18
19 public static void main(String[] args) throws Exception {
20 File source = new File( " test.xml " );
21 File specs = new File( " test.xsl " );
22 File target = new File( " test.pdf " );
23 FopFactory fopFactory = FopFactory.newInstance();
24 fopFactory.setUserConfig( " fop-config.xml " ); // 读取自定义配置
25 FOUserAgent foUserAgent = fopFactory.newFOUserAgent();
26 OutputStream out = new FileOutputStream(target);
27 out = new java.io.BufferedOutputStream(out);
28 try {
29 System.out.print( " Generating PDF![]()
"
);
30 Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, foUserAgent, out);
31 TransformerFactory factory = TransformerFactory.newInstance();
32 Transformer transformer = factory.newTransformer( new StreamSource(specs));
33 Source src = new StreamSource(source);
34 Result res = new SAXResult(fop.getDefaultHandler());
35 transformer.transform(src, res);
36 System.out.println( " Done. " );
37 } finally {
38 out.close();
39 }
40 }
41
42 }
2 import java.io.FileOutputStream;
3 import java.io.OutputStream;
4
5 import javax.xml.transform.Result;
6 import javax.xml.transform.Source;
7 import javax.xml.transform.Transformer;
8 import javax.xml.transform.TransformerFactory;
9 import javax.xml.transform.sax.SAXResult;
10 import javax.xml.transform.stream.StreamSource;
11
12 import org.apache.fop.apps.FOUserAgent;
13 import org.apache.fop.apps.Fop;
14 import org.apache.fop.apps.FopFactory;
15 import org.apache.fop.apps.MimeConstants;
16
17 public class Formatter {
18
19 public static void main(String[] args) throws Exception {
20 File source = new File( " test.xml " );
21 File specs = new File( " test.xsl " );
22 File target = new File( " test.pdf " );
23 FopFactory fopFactory = FopFactory.newInstance();
24 fopFactory.setUserConfig( " fop-config.xml " ); // 读取自定义配置
25 FOUserAgent foUserAgent = fopFactory.newFOUserAgent();
26 OutputStream out = new FileOutputStream(target);
27 out = new java.io.BufferedOutputStream(out);
28 try {
29 System.out.print( " Generating PDF
30 Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, foUserAgent, out);
31 TransformerFactory factory = TransformerFactory.newInstance();
32 Transformer transformer = factory.newTransformer( new StreamSource(specs));
33 Source src = new StreamSource(source);
34 Result res = new SAXResult(fop.getDefaultHandler());
35 transformer.transform(src, res);
36 System.out.println( " Done. " );
37 } finally {
38 out.close();
39 }
40 }
41
42 }
效果：
FOP的中文支持（其实是自定义字体支持），在0.94版本之前，十分有限，对每一个需要使用的TrueType字体，都需要生成一个metrics文件，在0.94和之后的版本，则没有这个要求，且可以自动扫描系统字体和指定文件夹中的TTF字体。如果不配置中文字体，默认情况下，中文字符在PDF中将被处理成"#"。
上面的示例代码虽然简单，但展示了FOP真正强大的地方，那就是控制力。这里篇幅有限，不可能全部特性都一一涉及，这个简单的例子至少可以让我们看到从原始的XML格式的数据，通过XSLT按照自定义的规则转换成XSL-FO，最后输出到PDF的过程，每一步都可以在Java代码之外进行严格控制。
以上是我对iText和FOP一些基本特点和用法的整理，它们各有特点，大家可以根据各自需要继续深入研究，FOP和iText相结合也未尝不可。希望能够帮助到有需要的朋友。