PDF to PDF Java Examples

This page contains various examples of using the PDF to PDF API in Java. The examples are complete and fully functional. Read more about how to convert PDF to PDF in Java.

Basic examples
Spring examples

Basic examples

Multiple PDFs to PDF file

import com.pdfcrowd.*;
import java.io.*;

public class ApiTest {
    public static void main(String[] args) throws IOException, Pdfcrowd.Error {
        try {
            // create the API client instance
            Pdfcrowd.PdfToPdfClient client =
                new Pdfcrowd.PdfToPdfClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

            // configure the conversion
            client.addPdfFile("/path/to/cover.pdf");
            client.addPdfFile("/path/to/proposal.pdf");
            client.addPdfFile("/path/to/price.pdf");
            client.addPdfFile("/path/to/contact.pdf");

            // run the conversion and write the result to a file
            client.convertToFile("offer.pdf");
        }
        catch(Pdfcrowd.Error why) {
            System.err.println("Pdfcrowd Error: " + why);
            throw why;
        }
        catch(IOException why) {
            System.err.println("IO Error: " + why);
            throw why;
        }
    }
}

Multiple PDFs to in-memory PDF

import com.pdfcrowd.*;
import java.io.*;

public class ApiTest {
    public static void main(String[] args) throws Pdfcrowd.Error {
        try {
            // create the API client instance
            Pdfcrowd.PdfToPdfClient client =
                new Pdfcrowd.PdfToPdfClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

            // configure the conversion
            client.addPdfFile("/path/to/cover.pdf");
            client.addPdfFile("/path/to/proposal.pdf");
            client.addPdfFile("/path/to/price.pdf");
            client.addPdfFile("/path/to/contact.pdf");

            // run the conversion and store the result into the "pdf" variable
            byte[] pdf = client.convert();

            // at this point the "pdf" variable contains PDF raw data and
            // can be sent in an HTTP response, saved to a file, etc.
        }
        catch(Pdfcrowd.Error why) {
            System.err.println("Pdfcrowd Error: " + why);
            throw why;
        }
    }
}

Multiple PDFs to PDF stream

import com.pdfcrowd.*;
import java.io.*;

public class ApiTest {
    public static void main(String[] args) throws IOException, Pdfcrowd.Error {
        try {
            // create the API client instance
            Pdfcrowd.PdfToPdfClient client =
                new Pdfcrowd.PdfToPdfClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

            // configure the conversion
            client.addPdfFile("/path/to/cover.pdf");
            client.addPdfFile("/path/to/proposal.pdf");
            client.addPdfFile("/path/to/price.pdf");
            client.addPdfFile("/path/to/contact.pdf");

            // create an output stream for the conversion result
            FileOutputStream outputStream = new FileOutputStream("offer.pdf");

            // run the conversion and write the result into the output stream
            client.convertToStream(outputStream);

            // close the output stream
            outputStream.close();
        }
        catch(Pdfcrowd.Error why) {
            System.err.println("Pdfcrowd Error: " + why);
            throw why;
        }
        catch(IOException why) {
            System.err.println("IO Error: " + why);
            throw why;
        }
    }
}

Multiple in-memory PDFs to PDF file

import com.pdfcrowd.*;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;

public class ApiTest {
    public static void main(String[] args) throws IOException, Pdfcrowd.Error {
        try {
            // create the API client instance
            Pdfcrowd.PdfToPdfClient client =
                new Pdfcrowd.PdfToPdfClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

            // configure the conversion
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/cover.pdf")));
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/proposal.pdf")));
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/price.pdf")));
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/contact.pdf")));

            // run the conversion and write the result to a file
            client.convertToFile("offer.pdf");
        }
        catch(Pdfcrowd.Error why) {
            System.err.println("Pdfcrowd Error: " + why);
            throw why;
        }
        catch(IOException why) {
            System.err.println("IO Error: " + why);
            throw why;
        }
    }
}

Join 2 in-memory PDFs together with 2 local PDF files to PDF file

import com.pdfcrowd.*;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;

public class ApiTest {
    public static void main(String[] args) throws IOException, Pdfcrowd.Error {
        try {
            // create the API client instance
            Pdfcrowd.PdfToPdfClient client =
                new Pdfcrowd.PdfToPdfClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

            // configure the conversion
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/cover.pdf")));
            client.addPdfFile("/path/to/proposal.pdf");
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/price.pdf")));
            client.addPdfFile("/path/to/contact.pdf");

            // run the conversion and write the result to a file
            client.convertToFile("offer.pdf");
        }
        catch(Pdfcrowd.Error why) {
            System.err.println("Pdfcrowd Error: " + why);
            throw why;
        }
        catch(IOException why) {
            System.err.println("IO Error: " + why);
            throw why;
        }
    }
}

Watermark a PDF file

import com.pdfcrowd.*;
import java.io.*;

public class ApiTest {
    public static void main(String[] args) throws IOException, Pdfcrowd.Error {
        try {
            // create the API client instance
            Pdfcrowd.PdfToPdfClient client =
                new Pdfcrowd.PdfToPdfClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

            // configure the conversion
            client.addPdfFile("/path/to/proposal.pdf");
            client.setPageWatermark("/path/to/watermark.pdf");

            // run the conversion and write the result to a file
            client.convertToFile("company_offer.pdf");
        }
        catch(Pdfcrowd.Error why) {
            System.err.println("Pdfcrowd Error: " + why);
            throw why;
        }
        catch(IOException why) {
            System.err.println("IO Error: " + why);
            throw why;
        }
    }
}

Linearize a PDF file

import com.pdfcrowd.*;
import java.io.*;

public class ApiTest {
    public static void main(String[] args) throws IOException, Pdfcrowd.Error {
        try {
            // create the API client instance
            Pdfcrowd.PdfToPdfClient client =
                new Pdfcrowd.PdfToPdfClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

            // configure the conversion
            client.addPdfFile("/path/to/not_linearized.pdf");
            client.setLinearize(true);

            // run the conversion and write the result to a file
            client.convertToFile("linearized.pdf");
        }
        catch(Pdfcrowd.Error why) {
            System.err.println("Pdfcrowd Error: " + why);
            throw why;
        }
        catch(IOException why) {
            System.err.println("IO Error: " + why);
            throw why;
        }
    }
}

Get info about the current conversion

import com.pdfcrowd.*;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;

public class ApiTest {
    public static void main(String[] args) throws IOException, Pdfcrowd.Error {
        try {
            // create the API client instance
            Pdfcrowd.PdfToPdfClient client =
                new Pdfcrowd.PdfToPdfClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

            // configure the conversion
            client.setDebugLog(true);
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/cover.pdf")));
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/proposal.pdf")));

            // run the conversion and write the result to a file
            client.convertToFile("offer.pdf");
            
            // print URL to the debug log
            System.out.println("Debug log url: " + client.getDebugLogUrl());
            
            // print the number of available conversion credits in your account
            System.out.println("Remaining credit count: " + client.getRemainingCreditCount());
            
            // print the number of credits consumed by the conversion
            System.out.println("Consumed credit count: " + client.getConsumedCreditCount());
            
            // print the unique ID of the conversion
            System.out.println("Job id: " + client.getJobId());
            
            // print the total number of pages in the output document
            System.out.println("Page count: " + client.getPageCount());
            
            // print the size of the output in bytes
            System.out.println("Output size: " + client.getOutputSize());
        }
        catch(Pdfcrowd.Error why) {
            System.err.println("Pdfcrowd Error: " + why);
            throw why;
        }
        catch(IOException why) {
            System.err.println("IO Error: " + why);
            throw why;
        }
    }
}

Spring examples

Multiple PDFs to PDF in Spring

import java.net.URLEncoder;
import java.io.UnsupportedEncodingException;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.http.ResponseEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import com.pdfcrowd.*;

@Controller
public class DemoController {
    // the recommended method is POST
    @PostMapping("/")
    public ResponseEntity<byte[]> convert() throws UnsupportedEncodingException {
        try {
            // create the API client instance
            Pdfcrowd.PdfToPdfClient client =
                new Pdfcrowd.PdfToPdfClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

            // configure the conversion
            client.addPdfFile("/path/to/cover.pdf");
            client.addPdfFile("/path/to/proposal.pdf");
            client.addPdfFile("/path/to/price.pdf");
            client.addPdfFile("/path/to/contact.pdf");

            // run the conversion and store the result into the "pdf" variable
            byte[] pdf = client.convert();

            // set HTTP response headers
            HttpHeaders headers = new HttpHeaders();
            headers.add("Content-Type", "application/pdf");
            headers.add("Cache-Control", "max-age=0");
            headers.add("Accept-Ranges", "none");
            headers.add("Content-Disposition", "attachment; filename*=UTF-8''" +
                        URLEncoder.encode("offer.pdf", "UTF-8").replace("+", "%20"));

            // send the result in the HTTP response
            return new ResponseEntity<>(pdf, headers, HttpStatus.OK);
        }
        catch(Pdfcrowd.Error why) {
            // send the error in the HTTP response
            HttpHeaders headers = new HttpHeaders();
            headers.add("Content-Type", "text/plain");
            String msg = String.format("Pdfcrowd Error: %d - %s",
                                       why.getCode(), why.getMessage());
            return new ResponseEntity<>(msg.getBytes(), headers, HttpStatus.BAD_REQUEST);
        }
    }
}

Multiple in-memory PDFs to PDF in Spring

import java.net.URLEncoder;
import java.io.UnsupportedEncodingException;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.http.ResponseEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import com.pdfcrowd.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.io.IOException;

@Controller
public class DemoController {
    // the recommended method is POST
    @PostMapping("/")
    public ResponseEntity<byte[]> convert() throws IOException, UnsupportedEncodingException {
        try {
            // create the API client instance
            Pdfcrowd.PdfToPdfClient client =
                new Pdfcrowd.PdfToPdfClient("demo", "ce544b6ea52a5621fb9d55f8b542d14d");

            // configure the conversion
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/cover.pdf")));
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/proposal.pdf")));
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/price.pdf")));
            client.addPdfRawData(Files.readAllBytes(Paths.get("/path/to/contact.pdf")));

            // run the conversion and store the result into the "pdf" variable
            byte[] pdf = client.convert();

            // set HTTP response headers
            HttpHeaders headers = new HttpHeaders();
            headers.add("Content-Type", "application/pdf");
            headers.add("Cache-Control", "max-age=0");
            headers.add("Accept-Ranges", "none");
            headers.add("Content-Disposition", "attachment; filename*=UTF-8''" +
                        URLEncoder.encode("offer.pdf", "UTF-8").replace("+", "%20"));

            // send the result in the HTTP response
            return new ResponseEntity<>(pdf, headers, HttpStatus.OK);
        }
        catch(Pdfcrowd.Error why) {
            // send the error in the HTTP response
            HttpHeaders headers = new HttpHeaders();
            headers.add("Content-Type", "text/plain");
            String msg = String.format("Pdfcrowd Error: %d - %s",
                                       why.getCode(), why.getMessage());
            return new ResponseEntity<>(msg.getBytes(), headers, HttpStatus.BAD_REQUEST);
        }
    }
}