Itext7 bare bones hello world example – how?

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So I’ve downloaded the compiled itext jar files from https://github.com/itext/itext7/releases/latest and placed them in same folder as the iText example C01E01_HelloWorld.java but when I run

javac C01E01_HelloWorld.java

I get

$ 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

I also tried

javac -cp /home/user01/itext/demo/ C01E01_HelloWorld.java

i.e. where the -cp points to where the iText jar’s (and C01E01_HelloWorld.java) is with same result. How do I get the import lines to know and use the iText jar files?

Or can this not be done in a simple way and need eclipse or maven or ?

So I ran the following without error

javac -cp kernel-7.1.13.jar:layout-7.1.13.jar:io-7.1.13.jar C01E01_HelloWorld.java 

if I left any of the jar files out it resulted in errors related to the missing jar. but when I try

java C01E01_HelloWorld 

I get

Error: Unable to initialize main class C01E01_HelloWorld
Caused by: java.lang.NoClassDefFoundError: com/itextpdf/layout/element/IBlockElement

I also tried

java -cp kernel-7.1.13.jar:layout-7.1.13.jar:io-7.1.13.jar C01E01_HelloWorld

which gave slightly different

Error: Could not find or load main class C01E01_HelloWorld
Caused by: java.lang.ClassNotFoundException: C01E01_HelloWorld

so next step yields

$ 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)

my source is

/*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();
    }
}

Answer

So I downloaded slf4j.api, slf4j-log4j12, and log4j using links provided in

SLF4J: Which .jar files does iText7 need exactly?

and also downloaded the compiled itext jar files from

https://github.com/itext/itext7/releases/latest

I then ran

javac -cp kernel-7.1.13.jar:layout-7.1.13.jar:io-7.1.13.jar:slf4j.api-1.6.1.jar:slf4j-log4j12-1.6.1.jar:log4j-1.2.16.jar C01E01_HelloWorld.java

and then

java -cp kernel-7.1.13.jar:layout-7.1.13.jar:io-7.1.13.jar:slf4j.api-1.6.1.jar:slf4j-log4j12-1.6.1.jar:log4j-1.2.16.jar:. C01E01_HelloWorld

and finally I get the alleged simple hello world pdf….

I’ve tried maven, eclipse, and now IDEA and failed to get any to “just” work following tutorials or hints …. yet



Source: stackoverflow