java - 获取 java.lang.NoClassDefFoundError : org/pdfbox/pdfparser/

Question

下面是我正在使用的代码，我提供了一个 pdf 文件和一个文本文件作为命令行的输入。

import org.pdfbox.cos.COSDocument;
import org.pdfbox.pdfparser.PDFParser;
import org.pdfbox.pdmodel.PDDocument;
import org.pdfbox.pdmodel.PDDocumentInformation;
import org.pdfbox.util.PDFTextStripper;

import java.io.File;
import java.io.FileInputStream;
import java.io.PrintWriter;

public class PDFTextParser {

    PDFParser parser;
    String parsedText;
    PDFTextStripper pdfStripper;
    PDDocument pdDoc;
    COSDocument cosDoc;
    PDDocumentInformation pdDocInfo;

    // PDFTextParser Constructor 
    public PDFTextParser() {
    }

    // Extract text from PDF Document
    String pdftoText(String fileName) {

        System.out.println("Parsing text from PDF file " + fileName + "....");
        File f = new File(fileName);

        if (!f.isFile()) {
            System.out.println("File " + fileName + " does not exist.");
            return null;
        }

        try {
            parser = new PDFParser(new FileInputStream(f));
        } catch (Exception e) {
            System.out.println("Unable to open PDF Parser.");
            return null;
        }

        try {
            parser.parse();
            cosDoc = parser.getDocument();
            pdfStripper = new PDFTextStripper();
            pdDoc = new PDDocument(cosDoc);
            parsedText = pdfStripper.getText(pdDoc);
        } catch (Exception e) {
            System.out.println("An exception occured in parsing the PDF Document.");
            e.printStackTrace();
            try {
                if (cosDoc != null) cosDoc.close();
                if (pdDoc != null) pdDoc.close();
            } catch (Exception e1) {
                e.printStackTrace();
            }
            return null;
        }
        System.out.println("Done.");
        return parsedText;
    }

    // Write the parsed text from PDF to a file
    void writeTexttoFile(String pdfText, String fileName) {

        System.out.println("\nWriting PDF text to output text file " + fileName + "....");
        try {
            PrintWriter pw = new PrintWriter(fileName);
            pw.print(pdfText);
            pw.close();  
        } catch (Exception e) {
            System.out.println("An exception occured in writing the pdf text to file.");
            e.printStackTrace();
        }
        System.out.println("Done.");
    }

    //Extracts text from a PDF Document and writes it to a text file
    public static void main(String args[]) {

        if (args.length != 2) {
            System.out.println("Usage: java PDFTextParser  ");
            System.exit(1);
        }

        PDFTextParser pdfTextParserObj = new PDFTextParser();
        String pdfToText = pdfTextParserObj.pdftoText(args[0]);

        if (pdfToText == null) {
            System.out.println("PDF to Text Conversion failed.");
        }
        else {
            System.out.println("\nThe text parsed from the PDF Document....\n" + pdfToText);
            pdfTextParserObj.writeTexttoFile(pdfToText, args[1]);
        }
    }
}

通过命令行运行此代码并输入 2 个 pdf 文件名和另一个文本文件名后，我收到 noClassDefFound 异常。下面是堆栈跟踪。

Exception in thread "main" java.lang.NoClassDefFoundError: org/pdfbox/pdfparser/
PDFParser
        at PDFTextParser.pdftoText(PDFTextParser.java:42)
        at PDFTextParser.main(PDFTextParser.java:93)
Caused by: java.lang.ClassNotFoundException: org.pdfbox.pdfparser.PDFParser
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
        ... 2 more

添加类路径后，我遇到异常

Exception in thread "main" java.lang.NoClassDefFoundError: org/fontbox/afm/AFMParser
        at org.pdfbox.pdmodel.font.PDFont.getAFM(PDFont.java:350)
        at org.pdfbox.pdmodel.font.PDFont.getAverageFontWidthFromAFMFile(PDFont.java:313)
        at org.pdfbox.pdmodel.font.PDSimpleFont.getAverageFontWidth(PDSimpleFont.java:231)
        at org.pdfbox.util.PDFStreamEngine.showString(PDFStreamEngine.java:276)
        at org.pdfbox.util.operator.ShowTextGlyph.process(ShowTextGlyph.java:80)
        at org.pdfbox.util.PDFStreamEngine.processOperator(PDFStreamEngine.java:452)
        at org.pdfbox.util.PDFStreamEngine.processSubStream(PDFStreamEngine.java:215)
        at org.pdfbox.util.PDFStreamEngine.processStream(PDFStreamEngine.java:174)
        at org.pdfbox.util.PDFTextStripper.processPage(PDFTextStripper.java:336)
        at org.pdfbox.util.PDFTextStripper.processPages(PDFTextStripper.java:259)
        at org.pdfbox.util.PDFTextStripper.writeText(PDFTextStripper.java:216)
        at org.pdfbox.util.PDFTextStripper.getText(PDFTextStripper.java:149)
        at PDFTextParser.pdftoText(PDFTextParser.java:53)
        at PDFTextParser.main(PDFTextParser.java:93)
Caused by: java.lang.ClassNotFoundException: org.fontbox.afm.AFMParser
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
        ... 14 more

Answer 1

在 Java 中运行具有外部依赖项(在您的情况下为 PDF 解析器)的程序时，您必须将适当的 JAR 文件包含到您的 CLASSPATH 中。

参见 this other thread on Stack Overflow或 the documentation at Oracle .

我搜索了在 jarfinder.com 上找不到的类，结果发现您需要(至少)包含两个不同的 JAR 文件 - font box和 pdf box JAR。