java使用PDFRenderer實(shí)現(xiàn)預(yù)覽PDF功能
更新時間:2018年12月19日 11:48:37 作者:OkidoGreen
這篇文章主要為大家詳細(xì)介紹了java使用PDFRenderer實(shí)現(xiàn)預(yù)覽PDF功能,具有一定的參考價值,感興趣的小伙伴們可以參考一下
本文實(shí)例為大家分享了java使用PDFRenderer實(shí)現(xiàn)預(yù)覽PDF功能,供大家參考,具體內(nèi)容如下
需要一個jar PDFRenderer-0.9.0.jar
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文檔在線以圖片格式預(yù)覽.
*
*/
@Action(value="/pdfPreview",results={@Result(name="pdf",location="/attachPreview/pdfViewer.jsp")})
public String pdfPreview() {
//按fileId查找出該文件的路徑以及文件名.
//該部分代碼copy自附件上傳組件
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(); // 文件所在磁盤路徑.
String fileName = upFile.getFileAllName(); // 真實(shí)文件名.
String saveFileName = upFile.getSaveFileName(); // 磁盤上的文件名.
String version = upFile.getVersion();
if ("old".equals(request.getParameter("ver"))){
if (version != null){
saveFileName = saveFileName.replace(".dat","_v"+version+".dat");
}
}
//當(dāng)前應(yīng)用絕對路徑
String appPath = request.getSession().getServletContext().getRealPath ("");
String imageSavePath = appPath + "\\preview_images\\";
//按照文件路徑讀取PDF文檔,并將其按頁轉(zhuǎn)換為圖片
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()))) { //如果轉(zhuǎn)換成功
return "pdf";
}else {
servletRequest.setAttribute("state", "f");
return "pdf";
}
}
}
/**
* 圖片文件在線預(yù)覽
*
*/
@Action(value="/imagePreview",results={@Result(name="image",location="/attachPreview/imageViewer.jsp")})
public String imagePreview() {
//按fileId查找出該文件的路徑以及文件名.
//該部分代碼copy自附件上傳組件
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(); // 文件所在磁盤路徑.
String fileName = upFile.getFileAllName(); // 真實(shí)文件名.
String saveFileName = upFile.getSaveFileName(); // 磁盤上的文件名.
String version = upFile.getVersion();
if ("old".equals(request.getParameter("ver"))){
if (version != null){
saveFileName = saveFileName.replace(".dat","_v"+version+".dat");
}
}
//當(dāng)前應(yīng)用絕對路徑
String appPath = request.getSession().getServletContext().getRealPath ("");
String imageSavePath = appPath + "\\preview_images\\";
//按照文件路徑讀取文件
String filePath = path + saveFileName ;
if(filePath == null || "".equals(filePath)) {
servletRequest.setAttribute("state", "f");
return "image";
}else {
//如果成功讀取文件
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文件讀取.
* @param filePath -- 待讀取文件的路徑.
* @param imageSavePath -- 圖片保存路徑.
* @param imageName -- 圖片文件保存后的文件名稱(包括后綴).
* @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()){ //判斷以文件名命名的文件夾是否存在.
file.mkdirs();
}
try {
InputStream is = new FileInputStream(filePath);
String imagePath = path + dirName + "." + extName;
FileOutputStream os = new FileOutputStream(imagePath); // 輸出到文件流.
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文檔讀取.
* @param filePath -- 待讀取PDF文件的路徑.
* @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文檔按頁轉(zhuǎn)換為圖片.
* @param pdfFile -- PDFFile instance
* @param imageSavePath -- 圖片保存路徑.
* @param fileName -- 保存圖片文件夾名稱.
*/
private boolean pdf2Images(PDFFile pdfFile,String imageSavePath,String fileName) {
if(pdfFile == null ) { //待轉(zhuǎn)換文檔不存在,返回false.
return false;
}
//將轉(zhuǎn)換后圖片存放于path路徑下
String path = imageSavePath + fileName + "\\";
File filePath = new File(path);
if(!filePath.exists()){ //判斷以文件名命名的文件夾是否存在.
filePath.mkdirs();
}
//取得當(dāng)前文件夾下的所有jpg格式的文件名.
String[] imageNames = filePath.list(new ImageFilter());
if(imageNames.length == 0) { //當(dāng)前文件夾下沒有文件.
//將pdf文檔按頁轉(zhuǎn)為圖片.
String imagePath = "";
try {
//對轉(zhuǎn)換頁數(shù)進(jìn)行限制,最多只轉(zhuǎn)換前maxPage頁.
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); // 輸出到文件流.
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(tag); // JPEG編碼.
out.close();
}
}catch (Exception ex) {
ex.printStackTrace();
return false;
}
}
//取得當(dāng)前文件夾下的所有jpg格式的文件名.
imageNames = filePath.list(new ImageFilter());
//對文件名排序.
Arrays.sort(imageNames,new FileNameComparator());
servletRequest.setAttribute("state", "s");
servletRequest.setAttribute("fileName", fileName);
servletRequest.setAttribute("imageNames", imageNames);
return true;
}
//圖片后綴名過濾類
//圖片jpg過濾器類
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);
}
}
//文件名稱比較類
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;
}
}
}
以上就是本文的全部內(nèi)容,希望對大家的學(xué)習(xí)有所幫助,也希望大家多多支持腳本之家。
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