动态jsp页面转PDF输出到页面

最近工作中遇到不少问题。总结一下。这段代码主要功能是将一个生成JSP页面转发成PDF输出到页面

需要利用ITEXT

String html = ServletUtils.forward(request,response,"/WEB-INF/jsp/depot/print/jhd.jsp");    //转发请求到jsp，返回解析之后的内容而不是输出到浏览器//System.out.println(html);byte[] pdf = PDFUtils.html2pdf(html);response.setContentType("application/pdf");response.setHeader("Content-Length",String.valueOf(pdf.length));response.setHeader("Connection","keep-alive");response.setHeader("Accept-Ranges","none");response.setHeader("X-Frame-Options","DENY");OutputStream out = response.getOutputStream();out.write(pdf);out.flush();

public class ServletUtils {

/**     * 此forward方法执行完毕之后不会输出内容到浏览器，而是把输出到字节流，最后以字符串的形式返回     * @param request     * @param response     * @param src     * @return     */    public static String forward(HttpServletRequest request, HttpServletResponse response, String src) {        try{

/*  ↓↓↓↓↓重新构造response，修改response中的输出流对象，使其输出到字节数组↓↓↓↓↓  */            final ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();            final ServletOutputStream servletOuputStream = new ServletOutputStream() {                @Override                public void write(int b) throws IOException {                    byteArrayOutputStream.write(b);                }                @Override                public boolean isReady() {                    return false;                }                @Override                public void setWriteListener(WriteListener writeListener) {                }            };

final PrintWriter printWriter = new PrintWriter(new OutputStreamWriter(byteArrayOutputStream, "UTF-8"));

response = new HttpServletResponseWrapper(response) {                public ServletOutputStream getOutputStream() {                    return servletOuputStream;                }                public PrintWriter getWriter() {                    return printWriter;                }            };             /*  ↑↑↑↑↑↑重新构造response，修改response中的输出流对象，使其输出到字节数组↑↑↑↑↑↑ */

//执行forward操作            request.getRequestDispatcher(src).forward(request,response);

//把字节流中的内容太转为字符串            return new String(byteArrayOutputStream.toByteArray(),"utf-8");        }        catch (Exception e){            throw new RuntimeException(e);        }    }}

import com.itextpdf.text.*;import com.itextpdf.text.pdf.PdfWriter;import com.itextpdf.tool.xml.Pipeline;import com.itextpdf.tool.xml.XMLWorker;import com.itextpdf.tool.xml.XMLWorkerFontProvider;import com.itextpdf.tool.xml.XMLWorkerHelper;import com.itextpdf.tool.xml.exceptions.CssResolverException;import com.itextpdf.tool.xml.html.CssAppliers;import com.itextpdf.tool.xml.html.CssAppliersImpl;import com.itextpdf.tool.xml.html.Tags;import com.itextpdf.tool.xml.parser.XMLParser;import com.itextpdf.tool.xml.pipeline.css.CSSResolver;import com.itextpdf.tool.xml.pipeline.css.CssResolverPipeline;import com.itextpdf.tool.xml.pipeline.end.PdfWriterPipeline;import com.itextpdf.tool.xml.pipeline.html.HtmlPipeline;import com.itextpdf.tool.xml.pipeline.html.HtmlPipelineContext;

import java.io.*;

/** * pdf工具类 */public class PDFUtils {

/**     * 把html转换成pdf，以字节数组的形式返回pdf文件     * @param html     * @return pdf字节数组     * @throws IOException     * @throws DocumentException     * @throws CssResolverException     */    public static byte[] html2pdf(String html) throws IOException, DocumentException,CssResolverException {        Document document = new Document(PageSize.A4);        ByteArrayOutputStream os = new ByteArrayOutputStream();        PdfWriter writer = PdfWriter.getInstance(document,os);        document.open();        XMLWorkerFontProvider fontProvider = new XMLWorkerFontProvider(){            @Override            public Font getFont(String fontname, String encoding, float size, int style) {                return super.getFont(fontname == null ? "宋体" : fontname, encoding, size, style);            }        };        fontProvider.addFontSubstitute("lowagie", "garamond");        fontProvider.setUseUnicode(true);        //使用我们的字体提供器，并将其设置为unicode字体样式        CssAppliers cssAppliers = new CssAppliersImpl(fontProvider);        HtmlPipelineContext htmlContext = new HtmlPipelineContext(cssAppliers);        htmlContext.setTagFactory(Tags.getHtmlTagProcessorFactory());        CSSResolver cssResolver = XMLWorkerHelper.getInstance().getDefaultCssResolver(true);        Pipeline<?> pipeline = new CssResolverPipeline(cssResolver,new HtmlPipeline(htmlContext, new PdfWriterPipeline(document,writer)));        XMLWorker worker = new XMLWorker(pipeline, true);        XMLParser p = new XMLParser(worker);        p.parse(new InputStreamReader(new ByteArrayInputStream(html.getBytes("gbk"))));        document.close();        return os.toByteArray();    }}