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通过 PDFRenderer 实现预览PDF 功能(pdf转成图片)

来源:  2017-08-25 14:13:25    评论:0点击:

需要一个jar PDFRenderer-0.9.0.jar 

http://download.csdn.net/download/oksdn/9950015

    package com.wonders.stpt.attach.action;  
      
    import java.awt.Image;  
    import java.awt.Rectangle;  
    import java.awt.image.BufferedImage;  
    import java.io.File;  
    import java.io.FileInputStream;  
    import java.io.FilenameFilter;  
    import java.io.FileOutputStream;  
    import java.io.InputStream;  
    import java.io.OutputStream;  
    import java.io.RandomAccessFile;  
    import java.nio.ByteBuffer;  
    import java.nio.channels.FileChannel;  
    import java.util.Arrays;  
    import java.util.Comparator;  
    import javax.imageio.*;  
      
    import javax.servlet.http.HttpServletRequest;  
    import javax.servlet.http.HttpServletResponse;  
      
    import org.apache.struts2.convention.annotation.Action;  
    import org.apache.struts2.convention.annotation.Namespace;  
    import org.apache.struts2.convention.annotation.ParentPackage;  
    import org.apache.struts2.convention.annotation.Result;  
    import org.springframework.beans.factory.annotation.Autowired;  
    import org.springframework.beans.factory.annotation.Qualifier;  
    import org.springframework.context.annotation.Scope;  
    import org.springframework.stereotype.Component;  
      
    import com.sun.image.codec.jpeg.JPEGCodec;  
      
    import com.sun.image.codec.jpeg.JPEGImageEncoder;  
    import com.sun.pdfview.PDFFile;  
    import com.sun.pdfview.PDFPage;  
    import com.wonders.stpt.attach.model.vo.UploadFile;  
    import com.wonders.stpt.attach.service.FjshService;  
    import com.wonders.stpt.userMsg.action.AbstractParamAction;  
      
      
      
    @SuppressWarnings("serial")  
    @ParentPackage("struts-default")  
    @Namespace(value="/attach")  
    @Component("attachViewerAction")  
    @Scope("prototype")  
    public class AttachViewerAction extends AbstractParamAction{  
          
        private FjshService fjshService;  
        private final int maxPage = 30;   
          
        public FjshService getFjshService() {  
            return fjshService;  
        }  
          
        @Autowired(required=false)  
        public void setFjshService(@Qualifier("fjshService")FjshService fjshService) {  
            this.fjshService = fjshService;  
        }  
      
          
        /**
         * PDF文档在线以图片格式预览.
         *  
         */  
        @Action(value="/pdfPreview",results={@Result(name="pdf",location="/attachPreview/pdfViewer.jsp")})  
        public String pdfPreview() {  
            //按fileId查找出该文件的路径以及文件名.  
            //该部分代码copy自附件上传组件  
      
            HttpServletRequest request = servletRequest;  
            HttpServletResponse response = servletResponse;       
            String fileId = request.getParameter("fileId");  
            if("".equals(fileId) || null == fileId) {  
                servletRequest.setAttribute("state", "f");  
                return "pdf";  
            }  
              
            UploadFile upFile = this.fjshService.loadFileById(fileId);  
            if(upFile == null) {  
                servletRequest.setAttribute("state", "f");  
                return "pdf";  
            }  
            String path = upFile.getPath();                 // 文件所在磁盘路径.  
            String fileName = upFile.getFileAllName();      // 真实文件名.  
            String saveFileName = upFile.getSaveFileName(); // 磁盘上的文件名.  
            String version = upFile.getVersion();  
            if ("old".equals(request.getParameter("ver"))){  
                if (version != null){  
                    saveFileName = saveFileName.replace(".dat","_v"+version+".dat");  
                }  
            }  
          
            //当前应用绝对路径  
            String appPath =  request.getSession().getServletContext().getRealPath ("");  
            String imageSavePath = appPath + "\\preview_images\\";  
              
            //按照文件路径读取PDF文档,并将其按页转换为图片  
      
            String filePath = path + saveFileName ;       
            if(filePath == null || "".equals(filePath)) {  
                servletRequest.setAttribute("state", "f");  
                return "pdf";  
            }else {  
                PDFFile pdfFile = this.getPdfFile(filePath);  
                if(this.pdf2Images(pdfFile,imageSavePath,String.valueOf(upFile.getId()))) { //如果转换成功  
                    return "pdf";  
                }else {  
                    servletRequest.setAttribute("state", "f");  
                    return "pdf";  
                }                     
            }                 
        }  
          
        /**
         * 图片文件在线预览
         *  
         */  
        @Action(value="/imagePreview",results={@Result(name="image",location="/attachPreview/imageViewer.jsp")})  
        public String imagePreview() {  
            //按fileId查找出该文件的路径以及文件名.  
            //该部分代码copy自附件上传组件  
      
            HttpServletRequest request = servletRequest;  
            HttpServletResponse response = servletResponse;       
            String fileId = request.getParameter("fileId");  
            if("".equals(fileId) || null == fileId) {  
                servletRequest.setAttribute("state", "f");  
                return "image";  
            }  
              
            UploadFile upFile = this.fjshService.loadFileById(fileId);  
            if(upFile == null) {  
                servletRequest.setAttribute("state", "f");  
                return "image";  
            }  
            String path = upFile.getPath();                 // 文件所在磁盘路径.  
            String fileName = upFile.getFileAllName();      // 真实文件名.  
            String saveFileName = upFile.getSaveFileName(); // 磁盘上的文件名.  
            String version = upFile.getVersion();  
            if ("old".equals(request.getParameter("ver"))){  
                if (version != null){  
                    saveFileName = saveFileName.replace(".dat","_v"+version+".dat");  
                }  
            }  
          
            //当前应用绝对路径  
            String appPath =  request.getSession().getServletContext().getRealPath ("");  
            String imageSavePath = appPath + "\\preview_images\\";  
              
            //按照文件路径读取文件  
            String filePath = path + saveFileName ;  
            if(filePath == null || "".equals(filePath)) {  
                servletRequest.setAttribute("state", "f");  
                return "image";  
            }else {  
                //如果成功读取文件  
                String imageName = String.valueOf(upFile.getId());  
                String extName = upFile.getFileExtName();  
                if(getImageFile(filePath,imageSavePath,imageName,extName)) {  
                    return "image";  
                }else {  
                    servletRequest.setAttribute("state", "f");  
                    return "image";  
                }     
            }     
        }  
          
        /**
         * image文件读取.  
         * @param filePath -- 待读取文件的路径.
         * @param imageSavePath -- 图片保存路径.
         * @param imageName -- 图片文件保存后的文件名称(包括后缀).
         * @return boolean instance.
         */  
        private boolean getImageFile(String filePath,String imageSavePath,String dirName,String extName) {        
            String path = imageSavePath + dirName + "\\";  
            File file = new File(path);  
            if(!file.exists()){ //判断以文件名命名的文件夹是否存在.  
                file.mkdirs();  
            }  
              
            try {  
                InputStream is = new FileInputStream(filePath);           
                String imagePath = path + dirName + "." + extName;  
                FileOutputStream os = new FileOutputStream(imagePath);  // 输出到文件流.  
                byte[] buffer = new byte[1024];  
                int n = 0;  
                while ((n = is.read(buffer, 0, 1024)) > 0) {  
                    os.write(buffer, 0, n);  
                }  
                os.close();  
                is.close();           
            } catch (Exception ex) {  
                ex.printStackTrace();  
                return false;  
            }     
              
            servletRequest.setAttribute("state", "s");  
            servletRequest.setAttribute("dirName", dirName);  
            servletRequest.setAttribute("imageName", dirName + "." + extName);  
            return true;  
        }  
          
        /**
         * PDF文档读取.  
         * @param filePath -- 待读取PDF文件的路径.
         * @return null 或者 PDFFile instance.
         */  
        private PDFFile getPdfFile(String filePath) {  
            try {  
                //load a pdf file from byte buffer.  
                File file = new File(filePath);  
                RandomAccessFile raf = new RandomAccessFile(file, "r");  
                FileChannel channel = raf.getChannel();  
                ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, 0,  
                        channel.size());  
                PDFFile pdfFile = new PDFFile(buf);  
      
                return pdfFile;  
            } catch (Exception ex) {  
                ex.printStackTrace();  
            }  
            return null;  
        }  
          
        /**
         * PDF文档按页转换为图片.
         * @param pdfFile -- PDFFile instance
         * @param imageSavePath -- 图片保存路径.
         * @param fileName -- 保存图片文件夹名称.
         */   
        private boolean pdf2Images(PDFFile pdfFile,String imageSavePath,String fileName) {  
            if(pdfFile == null ) { //待转换文档不存在,返回false.  
                return false;  
            }  
              
            //将转换后图片存放于path路径下  
      
            String path = imageSavePath + fileName + "\\";  
            File filePath = new File(path);  
            if(!filePath.exists()){ //判断以文件名命名的文件夹是否存在.  
                filePath.mkdirs();  
            }  
              
            //取得当前文件夹下的所有jpg格式的文件名.  
            String[] imageNames = filePath.list(new ImageFilter());       
            if(imageNames.length == 0) {  //当前文件夹下没有文件.  
                //将pdf文档按页转为图片.  
                String imagePath = "";  
                try {  
                    //对转换页数进行限制,最多只转换前maxPage页.  
                    int pages = pdfFile.getNumPages();  
                    if(pages > maxPage){  
                        pages = maxPage;  
                    }  
                      
                    for (int i = 1; i <= pages; i++) {  
                        // draw the page to an image  
                        PDFPage page = pdfFile.getPage(i);  
                        // get the width and height for the doc at the default zoom  
                        Rectangle rect = new Rectangle(0,   
                                                       0,   
                                                       (int) page.getBBox().getWidth(),   
                                                       (int) page.getBBox().getHeight());  
                        // generate the image  
                        Image img = page.getImage(rect.width, rect.height, // width & height  
                                                  rect, // clip rect  
                                                  null, // null for the ImageObserver  
                                                  true, // fill background with white  
                                                  true // block until drawing is done  
                                                  );  
                                                      
                        BufferedImage tag = new BufferedImage(rect.width,   
                                                              rect.height,  
                                                              BufferedImage.TYPE_INT_RGB);  
                          
                        tag.getGraphics().drawImage(img,   
                                                    0,  
                                                    0,  
                                                    rect.width,  
                                                    rect.height,  
                                                    null);  
                          
                          
                        imagePath = path + i + ".jpg";  
                        FileOutputStream out = new FileOutputStream(imagePath);  // 输出到文件流.  
                        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);  
                        encoder.encode(tag);        // JPEG编码.  
                        out.close();  
                    }                 
                }catch (Exception ex) {  
                    ex.printStackTrace();  
                    return false;  
                }  
            }  
              
            //取得当前文件夹下的所有jpg格式的文件名.  
            imageNames = filePath.list(new ImageFilter());  
            //对文件名排序.  
            Arrays.sort(imageNames,new FileNameComparator());  
              
            servletRequest.setAttribute("state", "s");  
            servletRequest.setAttribute("fileName", fileName);  
            servletRequest.setAttribute("imageNames", imageNames);  
              
            return true;  
        }  
          
        //图片后缀名过滤类  
          
        //图片jpg过滤器类  
        class ImageFilter implements FilenameFilter {  
             public boolean isImageFile(String fileName){  
                  if(fileName.toLowerCase().endsWith("jpg")) {  
                      return true;  
                  }else {  
                      return false;  
                  }         
             }  
               
             public ImageFilter() {}  
               
             public boolean accept(File dir,String name){  
                 return isImageFile(name);  
              }  
        }  
          
        //文件名称比较类  
      
        class FileNameComparator implements Comparator {  
            public final int compare(Object first, Object second) {  
               String[] fir = ((String)first).split("\\.");  
               String[] sec = ((String)second).split("\\.");  
                 
               int firstPage = Integer.parseInt(fir[0]);  
               int secondPage = Integer.parseInt(sec[0]);  
               int diff = firstPage - secondPage;  
               if (diff > 0)  
                return 1;  
               if (diff < 0)  
                return -1;  
               else  
                return 0;  
            }  
        }  
    } 


 

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