java remove pdf watermark Java去除PDF水印

import org.apache.pdfbox.cos.COSString;
import org.apache.pdfbox.exceptions.COSVisitorException;
import org.apache.pdfbox.pdfparser.PDFStreamParser;
import org.apache.pdfbox.pdfwriter.ContentStreamWriter;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.common.PDStream;
import org.apache.pdfbox.util.PDFOperator;

/**
 * 
 * 
 * 
	<!-- https://mvnrepository.com/artifact/org.apache.pdfbox/pdfbox -->
		<dependency>
		    <groupId>org.apache.pdfbox</groupId>
		    <artifactId>pdfbox</artifactId>
		    <version>1.8.3</version>
		</dependency>
 * @author Cloud-Top
 *
 */
public class PdfUtil {
	
	public static void main(String[] args) {
		removePdfWatermark("C:\\Users\\Cloud-Top\\eclipse-workspace\\demo\\src\\main\\resources\\watermark_pdf\\1629680832866.pdf",
				"C:\\Users\\Cloud-Top\\1629680832866.pdf");
	}

	/**
	 * 
	 * @param sourPath 原pdf
	 * @param savePath 新pdf
	 */
	@SuppressWarnings("unchecked")
	public static void removePdfWatermark(String sourPath ,String savePath) {
		try {
			//读取源文件
			PDDocument helloDocument = PDDocument.load(new File(sourPath));
			List<PDPage> allPages = helloDocument.getDocumentCatalog().getAllPages();
			for(PDPage pdPage : allPages) {
				PDStream contents = pdPage.getContents();
				PDFStreamParser parser = new PDFStreamParser(contents.getStream());  
	            parser.parse();  
	            List<Object> tokens = parser.getTokens();  
	            for (int j = 0; j < tokens.size(); j++) {  
	                Object next = tokens.get(j);  
	                if (next instanceof PDFOperator) {  
	                	PDFOperator op = (PDFOperator) next;  
	                    // Tj and TJ are the two operators that display strings in a PDF  
	                    if (op.getOperation().equals("Tj")) {  
	                        // Tj takes one operator and that is the string  
	                        // to display so lets update that operator  
	                        COSString previous = (COSString) tokens.get(j - 1);  
	                        String string = previous.getString();  
	                        System.out.println(string);
	                        //需要解决乱码
	                        //有效期至 == eHgó
	                        if(string.contains("eHgó")) {
	                        	//清空匹配上的内容
	                        	previous.reset();  
	                        }
	                    } 
	                }
	            } 
	            PDStream updatedStream = new PDStream(helloDocument);  
	            OutputStream out = updatedStream.createOutputStream();  
	            ContentStreamWriter tokenWriter = new ContentStreamWriter(out);  
	            tokenWriter.writeTokens(tokens);  
	            pdPage.setContents(updatedStream); 
			}
            //Output file name  
            helloDocument.save(savePath); 
            helloDocument.close();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (COSVisitorException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}