java 上傳文件-生成文件首頁縮略圖 生成pdf 抓取圖片

方法：1、文件轉換成pdf（采用openoffice或者jacob）

　　   2、抓取pdf首頁圖

第一步：采用jacob：

        a、下載jacob  注意區分32位，64位，否則不能用
　　　　將dll文件放在java bin目錄下即可
　　　　jar包引入項目

        b、轉換pdf

package cn.bnsr.edu_yun.util;

import java.io.File;  
  
import java.io.IOException;

import com.jacob.activeX.ActiveXComponent;  
import com.jacob.com.ComThread;  
import com.jacob.com.Dispatch;  
import com.jacob.com.Variant;  
	  
public class TestUtil {
	    static final int wdFormatPDF = 17;// PDF 格式    
	    public void wordToPDF(String sfileName,String toFileName){    
	            
	        System.out.println("啟動Word...");      
	        long start = System.currentTimeMillis();      
	        ActiveXComponent app = null;  
	        Dispatch doc = null;  
	        try {      
	            app = new ActiveXComponent("Word.Application");      
	            app.setProperty("Visible", new Variant(false));  
	            Dispatch docs = app.getProperty("Documents").toDispatch();   
//	          doc = Dispatch.call(docs,  "Open" , sourceFile).toDispatch();   
	            doc = Dispatch.invoke(docs,"Open",Dispatch.Method,new Object[] {                    
	               sfileName, new Variant(false),new Variant(true) }, new int[1]).toDispatch();               
	            System.out.println("打開文檔..." + sfileName);  
	            System.out.println("轉換文檔到PDF..." + toFileName);      
	            File tofile = new File(toFileName);      
	            if (tofile.exists()) {      
	                tofile.delete();      
	            }        
//	          Dispatch.call(doc, "SaveAs",  destFile,  17);                    
	            Dispatch.invoke(doc, "SaveAs", Dispatch.Method, new Object[] {                
	                toFileName, new Variant(17) }, new int[1]);    
	            long end = System.currentTimeMillis();      
	            System.out.println("轉換完成..用時：" + (end - start) + "ms.");                
	        } catch (Exception e) {  
	            e.printStackTrace();  
	            System.out.println("========Error:文檔轉換失敗：" + e.getMessage());      
	        } finally {  
	            Dispatch.call(doc,"Close",false);  
	            System.out.println("關閉文檔");  
	            if (app != null)      
	                app.invoke("Quit", new Variant[] {});      
	            }  
	          //如果沒有這句話,winword.exe進程將不會關閉  
	           ComThread.Release();     
	    }  
	    public static void main(String[] args) {  
	    	TestUtil d = new TestUtil();  
	        d.wordToPDF("D:\\work\\1111.docx", "d:\\work\\1111.pdf");  
	    }  
	  
}

第二步：抓取首頁圖：

　　

package cn.bnsr.edu_yun.util;

import java.awt.Image;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.security.AccessController;
import java.security.PrivilegedAction;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import com.sun.pdfview.PDFFile;
import com.sun.pdfview.PDFPage;

public class PdfImageUtil {
		// 將PDF格式的文件轉換為JPG格式的文件
	public static void pdfToJPG(String inputFile)throws IOException {
		// load a pdf from a byte buffer
		File file = new File(inputFile);
		RandomAccessFile raf = new RandomAccessFile(file, "r");
		FileChannel channel = raf.getChannel();
		//這句代碼通道建立了map映射,如果要刪除file那么得接觸映射
		ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, 0,
		channel.size());
		PDFFile pdffile = new PDFFile(buf);
		int totalpage =pdffile.getNumPages();
		for (int i = 1; i <= totalpage; i++) {
			if (i == 1) {
				// draw the first page to an image
				// 以圖片的形式來描繪首頁
				PDFPage page = pdffile.getPage(i);
				Rectangle rect = new Rectangle(0, 0, (int) page.getBBox().getWidth(), (int) page.getBBox().getHeight());
				// generate the image
				// 生成圖片
				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.getScaledInstance(rect.width, rect.height, Image.SCALE_SMOOTH), 0, 0, rect.width, rect.height,null);
		
				FileOutputStream out = new FileOutputStream( "D:\\work\\s111"+ ".jpg"); // 輸出到文件流
				JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
				encoder.encode(tag); // JPEG編碼
				// 關閉輸出流
				out.close();
				break;
			}
		}
		buf.clear();
		channel.close();
		raf.close();
		unmap(buf);
		file.delete();

	}
		//解除map映射
	public static <T> void unmap(final Object buffer) {
		AccessController.doPrivileged(new PrivilegedAction<T>(){
			@Override
			public T run() { 
				try {
					Method getCleanerMethod = buffer.getClass().getMethod("cleaner", new Class[0]);
					getCleanerMethod.setAccessible(true);
					sun.misc.Cleaner cleaner = (sun.misc.Cleaner) getCleanerMethod.invoke(buffer, new Object[0]);
					cleaner.clean();
				} catch(Exception e) {
					e.printStackTrace();
				} 
				return null;
			} 
		});
	}
		
}

　　

第三步、搞定，加入自己的業務邏輯，有問題歡迎提問。