所以我从https://github.com/itext/itext7/releases/latest下载了编译好的 itext jar 文件 ，并将它们放在与 iText 示例 C01E01_HelloWorld.java 相同的文件夹中，但是当我运行时
javac C01E01_HelloWorld.java
我明白了
$ javac C01E01_HelloWorld.java
C01E01_HelloWorld.java:3: error: package com.itextpdf.kernel.pdf does not exist
import com.itextpdf.kernel.pdf.PdfDocument;
^
C01E01_HelloWorld.java:4: error: package com.itextpdf.kernel.pdf does not exist
import com.itextpdf.kernel.pdf.PdfWriter;
^
C01E01_HelloWorld.java:5: error: package com.itextpdf.layout does not exist
import com.itextpdf.layout.Document;
^
C01E01_HelloWorld.java:6: error: package com.itextpdf.layout.element does not exist
import com.itextpdf.layout.element.Paragraph;
^
C01E01_HelloWorld.java:25: error: cannot find symbol
PdfWriter writer = new PdfWriter(dest);
^
symbol: class PdfWriter
location: class C01E01_HelloWorld
C01E01_HelloWorld.java:25: error: cannot find symbol
PdfWriter writer = new PdfWriter(dest);
^
symbol: class PdfWriter
location: class C01E01_HelloWorld
C01E01_HelloWorld.java:28: error: cannot find symbol
PdfDocument pdf = new PdfDocument(writer);
^
symbol: class PdfDocument
location: class C01E01_HelloWorld
C01E01_HelloWorld.java:28: error: cannot find symbol
PdfDocument pdf = new PdfDocument(writer);
^
symbol: class PdfDocument
location: class C01E01_HelloWorld
C01E01_HelloWorld.java:31: error: cannot find symbol
Document document = new Document(pdf);
^
symbol: class Document
location: class C01E01_HelloWorld
C01E01_HelloWorld.java:31: error: cannot find symbol
Document document = new Document(pdf);
^
symbol: class Document
location: class C01E01_HelloWorld
C01E01_HelloWorld.java:34: error: cannot find symbol
document.add(new Paragraph("Hello World!"));
^
symbol: class Paragraph
location: class C01E01_HelloWorld
11 errors
我也试过
javac -cp /home/user01/itext/demo/ C01E01_HelloWorld.java
即 -cp 指向 iText jar（和 C01E01_HelloWorld.java）的位置，结果相同。如何让导入行知道和使用 iText jar 文件？
或者这不能以简单的方式完成并且需要eclipse或maven或？
所以我运行以下没有错误
javac -cp kernel-7.1.13.jar:layout-7.1.13.jar:io-7.1.13.jar C01E01_HelloWorld.java
如果我遗漏了任何 jar 文件，则会导致与丢失 jar 相关的错误。但是当我尝试
java C01E01_HelloWorld
我明白了
Error: Unable to initialize main class C01E01_HelloWorld
Caused by: java.lang.NoClassDefFoundError: com/itextpdf/layout/element/IBlockElement
我也试过
java -cp kernel-7.1.13.jar:layout-7.1.13.jar:io-7.1.13.jar C01E01_HelloWorld
这略有不同
Error: Could not find or load main class C01E01_HelloWorld
Caused by: java.lang.ClassNotFoundException: C01E01_HelloWorld
所以下一步产生
$ java -cp kernel-7.1.13.jar:layout-7.1.13.jar:io-7.1.13.jar:. C01E01_HelloWorld
Exception in thread "main" java.lang.NullPointerException at C01E01_HelloWorld.main(C01E01_HelloWorld.java:21)
我的来源是
/*package tutorial.chapter01;*/
import com.itextpdf.kernel.pdf.PdfDocument;
import com.itextpdf.kernel.pdf.PdfWriter;
import com.itextpdf.layout.Document;
import com.itextpdf.layout.element.Paragraph;
import java.io.File;
import java.io.IOException;
/**
* Simple Hello World example.
*/
public class C01E01_HelloWorld {
/* public static final String DEST = "results/chapter01/hello_world.pdf"; */
public static final String DEST = "hello_world.pdf";
public static void main(String args[]) throws IOException {
File file = new File(DEST);
file.getParentFile().mkdirs();
new C01E01_HelloWorld().createPdf(DEST);
}
public void createPdf(String dest) throws IOException {
//Initialize PDF writer
PdfWriter writer = new PdfWriter(dest);
//Initialize PDF document
PdfDocument pdf = new PdfDocument(writer);
// Initialize document
Document document = new Document(pdf);
//Add paragraph to the document
document.add(new Paragraph("Hello World!"));
//Close document
document.close();
}
}