PDF to PDF API - Java

Join multiple PDF files in Java using the Pdfcrowd API v2. The API is easy to use and the integration takes only a couple of lines of code.

Installation

Download pdfcrowd-4.11.0-java.zip, unzip it and copy pdfcrowd-4.11.0.jar to your CLASSPATH.

Learn more about other install options (Maven, GitHub).

Authentication

Authentication is needed in order to use the Pdfcrowd API. The credentials used for accessing the API are your Pdfcrowd username and the API key.
Sign up for a Free Trial

Examples

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) {
            // report the error
            System.err.println("Pdfcrowd Error: " + why);

            // rethrow or handle the exception
            throw why;
        }
        catch(IOException why) {
            // report the error
            System.err.println("IO Error: " + why.getMessage());

            // rethrow or handle the exception
            throw why;
        }
    }
}
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 output file for conversion result
            FileOutputStream outputFile = new FileOutputStream("offer.pdf");

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

            // write the pdf into the output file
            outputFile.write(pdf);

            // close the output file
            outputFile.close();
        }
        catch(Pdfcrowd.Error why) {
            // report the error
            System.err.println("Pdfcrowd Error: " + why);

            // rethrow or handle the exception
            throw why;
        }
        catch(IOException why) {
            // report the error
            System.err.println("IO Error: " + why.getMessage());

            // rethrow or handle the exception
            throw why;
        }
    }
}
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 output stream for 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) {
            // report the error
            System.err.println("Pdfcrowd Error: " + why);

            // rethrow or handle the exception
            throw why;
        }
        catch(IOException why) {
            // report the error
            System.err.println("IO Error: " + why.getMessage());

            // rethrow or handle the exception
            throw why;
        }
    }
}
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) {
            // report the error
            System.err.println("Pdfcrowd Error: " + why);

            // rethrow or handle the exception
            throw why;
        }
        catch(IOException why) {
            // report the error
            System.err.println("IO Error: " + why.getMessage());

            // rethrow or handle the exception
            throw why;
        }
    }
}
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) {
            // report the error
            System.err.println("Pdfcrowd Error: " + why);

            // rethrow or handle the exception
            throw why;
        }
        catch(IOException why) {
            // report the error
            System.err.println("IO Error: " + why.getMessage());

            // rethrow or handle the exception
            throw why;
        }
    }
}
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) {
            // report the error
            System.err.println("Pdfcrowd Error: " + why);

            // rethrow or handle the exception
            throw why;
        }
        catch(IOException why) {
            // report the error
            System.err.println("IO Error: " + why.getMessage());

            // rethrow or handle the exception
            throw why;
        }
    }
}
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) {
            // report the error
            System.err.println("Pdfcrowd Error: " + why);

            // rethrow or handle the exception
            throw why;
        }
        catch(IOException why) {
            // report the error
            System.err.println("IO Error: " + why.getMessage());

            // rethrow or handle the exception
            throw why;
        }
    }
}
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) {
            // report the error
            System.err.println("Pdfcrowd Error: " + why);

            // rethrow or handle the exception
            throw why;
        }
        catch(IOException why) {
            // report the error
            System.err.println("IO Error: " + why.getMessage());

            // rethrow or handle the exception
            throw why;
        }
    }
}

Error Handling

try {
    // call the API 
}
catch(Pdfcrowd.Error why) {
    // print error
    System.err.println("Pdfcrowd Error: " + why);

    // print just error code
    System.err.println("Pdfcrowd Error Code: " + why.getCode());

    // print just error message
    System.err.println("Pdfcrowd Error Message: " + why.getMessage());

    // or handle the error in your way
}

Troubleshooting

API Reference - class PdfToPdfClient

Conversion from PDF to PDF. All setter methods return PdfToPdfClient object unless otherwise specified.

Constructor

public PdfToPdfClient(String userName, String apiKey)
Constructor for the Pdfcrowd API client.
userName
Your username at Pdfcrowd.
apiKey
Your API key.

 

PDF Manipulation

public PdfToPdfClient setAction(String action)
Specifies the action to be performed on the input PDFs.
action
Allowed values:
  • join
    Concatenate input PDFs into a single one.
  • shuffle
    Collate pages from input PDFs into a single one, take one page at a time from each input PDF. This is useful when combining two scanned documents containing odd and even pages.
Default: join
public byte[] convert()
Perform an action on the input files.
Returns
  • byte[] - Byte array containing the output PDF.
public void convertToStream(OutputStream outStream)
Perform an action on the input files and write the output PDF to an output stream.
outStream
The output stream that will contain the output PDF.
public void convertToFile(String filePath) throws IOException
Perform an action on the input files and write the output PDF to a file.
filePath
The output file path.
The string must not be empty.
public PdfToPdfClient addPdfFile(String filePath)
Add a PDF file to the list of the input PDFs.
filePath
The file path to a local PDF file.
The file must exist and not be empty.
public PdfToPdfClient addPdfRawData(byte[] pdfRawData)
Add in-memory raw PDF data to the list of the input PDFs.
Typical usage is for adding PDF created by another Pdfcrowd converter.

Example in PHP:
$clientPdf2Pdf->addPdfRawData($clientHtml2Pdf->convertUrl('http://www.example.com'));
pdfRawData
The raw PDF data.
The input data must be PDF content.

 

Watermark & Background

public PdfToPdfClient setPageWatermark(String pageWatermark)
Apply the first page of the watermark PDF to every page of the output PDF.
pageWatermark
The file path to a local watermark PDF file.
The file must exist and not be empty.
public PdfToPdfClient setPageWatermarkUrl(String pageWatermarkUrl)
Load a watermark PDF from the specified URL and apply the first page of the watermark PDF to every page of the output PDF.
pageWatermarkUrl
The supported protocols are http:// and https://.
Examples:
  • setPageWatermarkUrl("http://myserver.com/watermark.pdf")
public PdfToPdfClient setMultipageWatermark(String multipageWatermark)
Apply each page of the specified watermark PDF to the corresponding page of the output PDF.
multipageWatermark
The file path to a local watermark PDF file.
The file must exist and not be empty.
public PdfToPdfClient setMultipageWatermarkUrl(String multipageWatermarkUrl)
Load a watermark PDF from the specified URL and apply each page of the specified watermark PDF to the corresponding page of the output PDF.
multipageWatermarkUrl
The supported protocols are http:// and https://.
Examples:
  • setMultipageWatermarkUrl("http://myserver.com/watermark.pdf")
public PdfToPdfClient setPageBackground(String pageBackground)
Apply the first page of the specified PDF to the background of every page of the output PDF.
pageBackground
The file path to a local background PDF file.
The file must exist and not be empty.
public PdfToPdfClient setPageBackgroundUrl(String pageBackgroundUrl)
Load a background PDF from the specified URL and apply the first page of the background PDF to every page of the output PDF.
pageBackgroundUrl
The supported protocols are http:// and https://.
Examples:
  • setPageBackgroundUrl("http://myserver.com/background.pdf")
public PdfToPdfClient setMultipageBackground(String multipageBackground)
Apply each page of the specified PDF to the background of the corresponding page of the output PDF.
multipageBackground
The file path to a local background PDF file.
The file must exist and not be empty.
public PdfToPdfClient setMultipageBackgroundUrl(String multipageBackgroundUrl)
Load a background PDF from the specified URL and apply each page of the specified background PDF to the corresponding page of the output PDF.
multipageBackgroundUrl
The supported protocols are http:// and https://.
Examples:
  • setMultipageBackgroundUrl("http://myserver.com/background.pdf")

 

PDF Format

Miscellaneous values for PDF output.

public PdfToPdfClient setLinearize(boolean linearize)
Create linearized PDF. This is also known as Fast Web View.
linearize
Set to true to create linearized PDF.
Default: false
public PdfToPdfClient setEncrypt(boolean encrypt)
Encrypt the PDF. This prevents search engines from indexing the contents.
encrypt
Set to true to enable PDF encryption.
Default: false
public PdfToPdfClient setUserPassword(String userPassword)
Protect the PDF with a user password. When a PDF has a user password, it must be supplied in order to view the document and to perform operations allowed by the access permissions.
userPassword
The user password.
public PdfToPdfClient setOwnerPassword(String ownerPassword)
Protect the PDF with an owner password. Supplying an owner password grants unlimited access to the PDF including changing the passwords and access permissions.
ownerPassword
The owner password.
public PdfToPdfClient setNoPrint(boolean noPrint)
Disallow printing of the output PDF.
noPrint
Set to true to set the no-print flag in the output PDF.
Default: false
public PdfToPdfClient setNoModify(boolean noModify)
Disallow modification of the output PDF.
noModify
Set to true to set the read-only only flag in the output PDF.
Default: false
public PdfToPdfClient setNoCopy(boolean noCopy)
Disallow text and graphics extraction from the output PDF.
noCopy
Set to true to set the no-copy flag in the output PDF.
Default: false

 

Viewer Preferences

These preferences specify how a PDF viewer should present the document. The preferences may be ignored by some PDF viewers.

public PdfToPdfClient setPageLayout(String pageLayout)
Specify the page layout to be used when the document is opened.
pageLayout
Allowed values:
  • single-page
    Display one page at a time.
  • one-column
    Display the pages in one column.
  • two-column-left
    Display the pages in two columns, with odd-numbered pages on the left.
  • two-column-right
    Display the pages in two columns, with odd-numbered pages on the right.
public PdfToPdfClient setPageMode(String pageMode)
Specify how the document should be displayed when opened.
pageMode
Allowed values:
  • full-screen
    Full-screen mode.
  • thumbnails
    Thumbnail images are visible.
  • outlines
    Document outline is visible.
public PdfToPdfClient setInitialZoomType(String initialZoomType)
Specify how the page should be displayed when opened.
initialZoomType
Allowed values:
  • fit-width
    The page content is magnified just enough to fit the entire width of the page within the window.
  • fit-height
    The page content is magnified just enough to fit the entire height of the page within the window.
  • fit-page
    The page content is magnified just enough to fit the entire page within the window both horizontally and vertically. If the required horizontal and vertical magnification factors are different, use the smaller of the two, centering the page within the window in the other dimension.
public PdfToPdfClient setInitialPage(int initialPage)
Display the specified page when the document is opened.
initialPage
Must be a positive integer number.
public PdfToPdfClient setInitialZoom(int initialZoom)
Specify the initial page zoom in percents when the document is opened.
initialZoom
Must be a positive integer number.
public PdfToPdfClient setHideToolbar(boolean hideToolbar)
Specify whether to hide the viewer application's tool bars when the document is active.
hideToolbar
Set to true to hide tool bars.
Default: false
public PdfToPdfClient setHideMenubar(boolean hideMenubar)
Specify whether to hide the viewer application's menu bar when the document is active.
hideMenubar
Set to true to hide the menu bar.
Default: false
public PdfToPdfClient setHideWindowUi(boolean hideWindowUi)
Specify whether to hide user interface elements in the document's window (such as scroll bars and navigation controls), leaving only the document's contents displayed.
hideWindowUi
Set to true to hide ui elements.
Default: false
public PdfToPdfClient setFitWindow(boolean fitWindow)
Specify whether to resize the document's window to fit the size of the first displayed page.
fitWindow
Set to true to resize the window.
Default: false
public PdfToPdfClient setCenterWindow(boolean centerWindow)
Specify whether to position the document's window in the center of the screen.
centerWindow
Set to true to center the window.
Default: false
public PdfToPdfClient setDisplayTitle(boolean displayTitle)
Specify whether the window's title bar should display the document title. If false , the title bar should instead display the name of the PDF file containing the document.
displayTitle
Set to true to display the title.
Default: false
public PdfToPdfClient setRightToLeft(boolean rightToLeft)
Set the predominant reading order for text to right-to-left. This option has no direct effect on the document's contents or page numbering but can be used to determine the relative positioning of pages when displayed side by side or printed n-up
rightToLeft
Set to true to set right-to-left reading order.
Default: false

 

Miscellaneous

public PdfToPdfClient setDebugLog(boolean debugLog)
Turn on the debug logging. Details about the conversion are stored in the debug log. The URL of the log can be obtained from the getDebugLogUrl method or available in conversion statistics.
debugLog
Set to true to enable the debug logging.
Default: false
public String getDebugLogUrl()
Get the URL of the debug log for the last conversion.
Returns
  • String - The link to the debug log.
public int getRemainingCreditCount()
Get the number of conversion credits available in your account.
This method can only be called after a call to one of the convertXYZ methods.
The returned value can differ from the actual count if you run parallel conversions.
The special value 999999 is returned if the information is not available.
Returns
  • int - The number of credits.
public int getConsumedCreditCount()
Get the number of credits consumed by the last conversion.
Returns
  • int - The number of credits.
public String getJobId()
Get the job id.
Returns
  • String - The unique job identifier.
public int getPageCount()
Get the total number of pages in the output document.
Returns
  • int - The page count.
public int getOutputSize()
Get the size of the output in bytes.
Returns
  • int - The count of bytes.
public PdfToPdfClient setTag(String tag)
Tag the conversion with a custom value. The tag is used in conversion statistics. A value longer than 32 characters is cut off.
tag
A string with the custom tag.

 

API Client Options

public PdfToPdfClient setUseHttp(boolean useHttp)
Specifies if the client communicates over HTTP or HTTPS with Pdfcrowd API.
useHttp
Set to true to use HTTP.
Default: false
public PdfToPdfClient setUserAgent(String userAgent)
Set a custom user agent HTTP header. It can be usefull if you are behind some proxy or firewall.
userAgent
The user agent string.
Default: pdfcrowd_java_client/4.11.0 (http://pdfcrowd.com)
public PdfToPdfClient setProxy(String host, int port, String userName, String password)
Specifies an HTTP proxy that the API client library will use to connect to the internet.
host
The proxy hostname.
port
The proxy port.
userName
The username.
password
The password.
public PdfToPdfClient setRetryCount(int retryCount)
Specifies the number of retries when the 502 HTTP status code is received. The 502 status code indicates a temporary network issue. This feature can be disabled by setting to 0.
retryCount
Number of retries wanted.
Default: 1