Article summary

Summary

Discusses how to create an Apache Sling Servlet that accepts a file posted from a Java Swing application. The Sling Servlet persists the file in the specified client libs folder. This article also discusses how to configure the Sling Servlet so that authentication is not required. In addition, discusses how to use the JCR API to write binary data to nodes. 

This article uses an Adobe Maven Archetype project to build an OSGi bundle. If you are not familiar with an Adobe Maven Archetype project, it is recommended that you read the following article: Creating your first AEM Service using an Adobe Maven Archetype project.

Digital Marketing Solution(s) Adobe Experience Manager (Adobe CQ)
Audience
Developer (intermediate)
Required Skills
Java, Maven, JCR, Sling
AEM Version(s) Adobe Experience Manager 5.5, 5.6, 6.x
Video https://youtu.be/YuqBgrVzD2A

Note:

You can download both the required Sling Servlet and the Java Swing Client that is discussed in this article. This is a sample application (same code as shown in this article).  Included in the ZIP is both the Java Swing application and the the OSGi bundle. Unzip the file and retrieve the JAR OSGi file. Deploy the JAR (OSGi bundle) to AEM using the Felix console. You can find the JAR file at FileUpload\OSGi. You can run the client by using the BAT file. 

Download

Note:

Make sure before you run the Java client application, you have installed the OSGi bundle and placed it into an Active state. 

Introduction

You can create a custom Java Swing client application that lets a user select a file from the local desktop and post the file to an AEM ClientLibs folder. In most AEM applications, you create a ClientLibs folder to store required application files such as CSS file and JS files. In some cases, you can place third-party files like JQuery JS files when you want to incorporate functionality offered by these files into your AEM application.

The following illustration shows CSS and JS files located in an AEM client libs folder.

ClientLibs

Note:

There are other ways to get files into a ClientLibs folder. For example, you can use the CRXDE tool to drag and drop files from the local desktop to a ClientLibs folder. However, there are drawbacks to using CRXDE to drag and drop files from the desktop to an AEM client libs folder. In some situations, you may encounter performance issues.  

To develop a Java Swing application that posts files to an AEM client libs folder, you use Java APIs located in the org.apache.http package. The APIs located in this package lets you post files to a custom AEM Sling Servlet. The Sling Servlet saves the file in the specified ClientLibs folder using the JCR API.  

PostAEM

The following illustration shows the Java client application that is created in this development article.
 

JavaClient


This development article guides you through creating the Java Swing application that posts files and the AEM Sling Servlet. The custom Sling Servlet is is implemented as an OSGi bundle that is built using Declarative Services (DS) and Maven. DS is used to inject a ResourceResolverFactory instance into the service. The OSGi bundle is a managed component, which means that the OSGi service container creates the ResourceResolverFactory instance.

Note:

For more information about a ClientLibs folder, see Using Client-Side Libraries.

Create the client application using Java Swing classes.

The first step is to create an IntelliJ Maven Java project as shown here.

ClientProject

Create an IntelliJ project by performing these tasks:

  1. Start IntelliJ IDEA.
  2. Click File, New Project.
  3. Select Maven Module.
  4. In Project Name, type SwingFileUpload.
  5. In Project Location, specify a location for your project. In this example, C:\SwingFileUpload is specified.
  6. In the Project SDK, specify the location to your Java SDK location.
  7. Click Next.
  8. Click Finish.  

Next, add the following dependencies to the POM file in your IntelliJ project: 

<dependencies>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.0-alpha4</version>
        </dependency>

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
            <version>4.1-beta1</version>
        </dependency>
</dependencies>

Notice that these dependencies include the org.apache.httpcomponents. This dependency lets you use post files from the desktop to an AEM ClientLibs folder.  

Create the PostFile class

The PostFile class extends JFrame and represents the frame of your Java application. For information about the JFrame class, see JFrame.

The PostFile class also contains a Java main method that represents the entry point into your Java application, as shown here.

public static void main(String[] args) {

    SwingUtilities.invokeLater(new Runnable() {
    public void run() {
    UIManager.put("swing.boldMetal", Boolean.FALSE);
    createAndShowGUI();
    }
    });
}

The following Java method posts a file that the user selects to the specified AEM ClientLibs folder. The Sling Servlet used in this use case does not require authentication. As a result, the Sling Servlet is configured so that authentication is not required. (The syntax is shown later.)

The URL to the AEM server (and port) is specified by the user. The value /bin/upload file is specified when developing the Sling Servlet by defining the @SlingServlet annotation value (this is shown later in this development article).

To post a file, you use an org.apache.http.impl.client.DefaultHttpClient instance. Invoke this object's execute method and pass the HttpPost instance. This instance contains two values that are posted to the Sling Servlet:

  1. The file that the user selected.
  2. The path of the ClientLibs folder.

//Posts the selected file to AEM
    private static void postAEM(File file, String host, String path, String mimeType)
    {
        try {

            String aemPostUrl = host+"/bin/upfile";
             HttpPost post = new HttpPost(aemPostUrl);
            org.apache.http.entity.mime.MultipartEntity entity = new org.apache.http.entity.mime.MultipartEntity ();
            byte[] b = new byte[(int)file.length()];
            org.apache.http.entity.mime.content.FileBody fileBody = new org.apache.http.entity.mime.content.FileBody(file, mimeType) ;
            org.apache.http.entity.mime.content.StringBody imageTitle = new org.apache.http.entity.mime.content.StringBody(path);

            entity.addPart("imageTitle", imageTitle);
            entity.addPart("image", fileBody);
            post.setEntity(entity);

            org.apache.http.impl.client.DefaultHttpClient client = new org.apache.http.impl.client.DefaultHttpClient();
            org.apache.http.HttpResponse response = null;

            response = client.execute(post);
            System.out.println("Done") ;
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

The following Java code represents the entire PostFile class.

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.SwingUtilities;
import org.apache.http.client.methods.*;


/*
 * Posts a file to an AEM Sling Servlet
 */
public class PostFile extends JPanel
        implements ActionListener {
    static private final String newline = "\n";
    JButton postButton, clearButton;
    JTextArea log;
    JTextField hostField;
    JTextField path;
    JFileChooser fc;

    static  String aemURL;

    JTextField queryField;
    JComboBox patternList;
    int m_stars = -1;

    String[] mimeType = {
            "text/javascript",
            "text/css",
            "text/plain",

    };

    public PostFile() {
        super(new BorderLayout());

        //Create the log first, because the action listeners
        //need to refer to it.
        log = new JTextArea(5,20);
        log.setMargin(new Insets(5,5,5,5));
        log.setEditable(false);
        JScrollPane logScrollPane = new JScrollPane(log);

        //Create a file chooser
        fc = new JFileChooser();

        //Create the post button.
        postButton = new JButton("Post File...",
                createImageIcon("images/Open16.gif"));
        postButton.addActionListener(this);

        //Create the clear button.
        clearButton = new JButton("Clear...",
                createImageIcon("images/Save16.gif"));
        clearButton.addActionListener(this);

        //For layout purposes, put the buttons in a separate panel
        JPanel buttonPanel = new JPanel(); //use FlowLayout

        buttonPanel.setLayout(new GridLayout(5, 2));
        buttonPanel.add(new JLabel("Enter the AEM URL: "));
        buttonPanel.add(hostField = new JTextField());
        hostField.setText("http://localhost:4502"); // Set default for AEM URL
        buttonPanel.add(new JLabel("Enter the AEM Path: "));
        buttonPanel.add(path = new JTextField());
        path.setText("/apps/slingSevletApp/components/clientlibs"); // Set default for AEM URL


        buttonPanel.add(new JLabel("File MIME type: "));
        buttonPanel.add(patternList = new JComboBox(mimeType));

        buttonPanel.add(postButton);
        buttonPanel.add(clearButton);

        //Add the buttons and the log to this panel.
        add(buttonPanel, BorderLayout.PAGE_START);
        add(logScrollPane, BorderLayout.CENTER);
    }

    public void actionPerformed(ActionEvent e) {

        //Handle open button action.
        if (e.getSource() == postButton) {
            int returnVal = fc.showOpenDialog(PostFile.this);

            if (returnVal == JFileChooser.APPROVE_OPTION) {
                File file = fc.getSelectedFile();

                //Get the path & server value
                String myPath = path.getText();
                String aemUrl = hostField.getText();
                String mimeType =(String) patternList.getSelectedItem() ;

                //This is where a real application would open the file.
                postAEM(file, aemUrl, myPath, mimeType);
                log.append("Successfully posted " + file.getName() + " to "+myPath +"." + newline);
            } else {
                log.append("Open command cancelled by user." + newline);
            }
            log.setCaretPosition(log.getDocument().getLength());

            //Handle clear button action.
        } else if (e.getSource() == clearButton) {
            log.setText("");
        }
    }

    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) {
        java.net.URL imgURL = PostFile.class.getResource(path);
        if (imgURL != null) {
            return new ImageIcon(imgURL);
        } else {
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event dispatch thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("AEM File Uploader");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Add content to the window.
        frame.add(new PostFile());

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }


    //Posts the selected file to AEM
    private static void postAEM(File file, String host, String path, String mimeType)
    {
        try {

            String aemPostUrl = host+"/bin/upfile";
             HttpPost post = new HttpPost(aemPostUrl);
            org.apache.http.entity.mime.MultipartEntity entity = new org.apache.http.entity.mime.MultipartEntity ();
            byte[] b = new byte[(int)file.length()];
            org.apache.http.entity.mime.content.FileBody fileBody = new org.apache.http.entity.mime.content.FileBody(file, mimeType) ;
            org.apache.http.entity.mime.content.StringBody imageTitle = new org.apache.http.entity.mime.content.StringBody(path);

            entity.addPart("imageTitle", imageTitle);
            entity.addPart("image", fileBody);
            post.setEntity(entity);



            org.apache.http.impl.client.DefaultHttpClient client = new org.apache.http.impl.client.DefaultHttpClient();
            org.apache.http.HttpResponse response = null;

            response = client.execute(post);
            System.out.println("Done") ;
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                //Turn off metal's use of bold fonts
                UIManager.put("swing.boldMetal", Boolean.FALSE);
                createAndShowGUI();
            }
        });
    }
}

Setup Maven in your development environment

You can use Maven to build an OSGi bundle that contains a Sling Servlet. Maven manages required JAR files that a Java project needs in its class path. Instead of searching the Internet trying to find and download third-party JAR files to include in your project’s class path, Maven manages these dependencies for you.

You can download Maven 3 from the following URL:

http://maven.apache.org/download.html

After you download and extract Maven, create an environment variable named M3_HOME. Assign the Maven install location to this environment variable. For example:

C:\Programs\Apache\apache-maven-3.0.4

Set up a system environment variable to reference Maven. To test whether you properly setup Maven, enter the following Maven command into a command prompt:

%M3_HOME%\bin\mvn -version

This command provides Maven and Java install details and resembles the following message:

Java home: C:\Programs\Java64-6\jre
Default locale: en_US, platform encoding: Cp1252
OS name: "windows 7", version: "6.1", arch: "amd64", family: "windows"

Note:

It is recommended that you use Maven 3.0.3 or greater.  For more information about setting up Maven and the Home variable, see: Maven in 5 Minutes.

The following XML code represents a settings.xml file that you can use.

<?xml version="1.0" encoding="UTF-8"?>

<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License.  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.
-->

<!--
 | This is the configuration file for Maven. It can be specified at two levels:
 |
 |  1. User Level. This settings.xml file provides configuration for a single user, 
 |                 and is normally provided in ${user.home}/.m2/settings.xml.
 |
 |                 NOTE: This location can be overridden with the CLI option:
 |
 |                 -s /path/to/user/settings.xml
 |
 |  2. Global Level. This settings.xml file provides configuration for all Maven
 |                 users on a machine (assuming they're all using the same Maven
 |                 installation). It's normally provided in 
 |                 ${maven.home}/conf/settings.xml.
 |
 |                 NOTE: This location can be overridden with the CLI option:
 |
 |                 -gs /path/to/global/settings.xml
 |
 | The sections in this sample file are intended to give you a running start at
 | getting the most out of your Maven installation. Where appropriate, the default
 | values (values used when the setting is not specified) are provided.
 |
 |-->
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0" 
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
          xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
  <!-- localRepository
   | The path to the local repository maven will use to store artifacts.
   |
   | Default: ~/.m2/repository
  <localRepository>/path/to/local/repo</localRepository>
  -->

  <!-- interactiveMode
   | This will determine whether maven prompts you when it needs input. If set to false,
   | maven will use a sensible default value, perhaps based on some other setting, for
   | the parameter in question.
   |
   | Default: true
  <interactiveMode>true</interactiveMode>
  -->

  <!-- offline
   | Determines whether maven should attempt to connect to the network when executing a build.
   | This will have an effect on artifact downloads, artifact deployment, and others.
   |
   | Default: false
  <offline>false</offline>
  -->

  <!-- pluginGroups
   | This is a list of additional group identifiers that will be searched when resolving plugins by their prefix, i.e.
   | when invoking a command line like "mvn prefix:goal". Maven will automatically add the group identifiers
   | "org.apache.maven.plugins" and "org.codehaus.mojo" if these are not already contained in the list.
   |-->
  <pluginGroups>
    <!-- pluginGroup
     | Specifies a further group identifier to use for plugin lookup.
    <pluginGroup>com.your.plugins</pluginGroup>
    -->
  </pluginGroups>

  <!-- proxies
   | This is a list of proxies which can be used on this machine to connect to the network.
   | Unless otherwise specified (by system property or command-line switch), the first proxy
   | specification in this list marked as active will be used.
   |-->
  <proxies>
    <!-- proxy
     | Specification for one proxy, to be used in connecting to the network.
     |
    <proxy>
      <id>optional</id>
      <active>true</active>
      <protocol>http</protocol>
      <username>proxyuser</username>
      <password>proxypass</password>
      <host>proxy.host.net</host>
      <port>80</port>
      <nonProxyHosts>local.net|some.host.com</nonProxyHosts>
    </proxy>
    -->
  </proxies>

  <!-- servers
   | This is a list of authentication profiles, keyed by the server-id used within the system.
   | Authentication profiles can be used whenever maven must make a connection to a remote server.
   |-->
  <servers>
    <!-- server
     | Specifies the authentication information to use when connecting to a particular server, identified by
     | a unique name within the system (referred to by the 'id' attribute below).
     | 
     | NOTE: You should either specify username/password OR privateKey/passphrase, since these pairings are 
     |       used together.
     |
    <server>
      <id>deploymentRepo</id>
      <username>repouser</username>
      <password>repopwd</password>
    </server>
    -->
    
    <!-- Another sample, using keys to authenticate.
    <server>
      <id>siteServer</id>
      <privateKey>/path/to/private/key</privateKey>
      <passphrase>optional; leave empty if not used.</passphrase>
    </server>
    -->
  </servers>

  <!-- mirrors
   | This is a list of mirrors to be used in downloading artifacts from remote repositories.
   | 
   | It works like this: a POM may declare a repository to use in resolving certain artifacts.
   | However, this repository may have problems with heavy traffic at times, so people have mirrored
   | it to several places.
   |
   | That repository definition will have a unique id, so we can create a mirror reference for that
   | repository, to be used as an alternate download site. The mirror site will be the preferred 
   | server for that repository.
   |-->
  <mirrors>
    <!-- mirror
     | Specifies a repository mirror site to use instead of a given repository. The repository that
     | this mirror serves has an ID that matches the mirrorOf element of this mirror. IDs are used
     | for inheritance and direct lookup purposes, and must be unique across the set of mirrors.
     |
    <mirror>
      <id>mirrorId</id>
      <mirrorOf>repositoryId</mirrorOf>
      <name>Human Readable Name for this Mirror.</name>
      <url>http://my.repository.com/repo/path</url>
    </mirror>
     -->
  </mirrors>
  
  <!-- profiles
   | This is a list of profiles which can be activated in a variety of ways, and which can modify
   | the build process. Profiles provided in the settings.xml are intended to provide local machine-
   | specific paths and repository locations which allow the build to work in the local environment.
   |
   | For example, if you have an integration testing plugin - like cactus - that needs to know where
   | your Tomcat instance is installed, you can provide a variable here such that the variable is 
   | dereferenced during the build process to configure the cactus plugin.
   |
   | As noted above, profiles can be activated in a variety of ways. One way - the activeProfiles
   | section of this document (settings.xml) - will be discussed later. Another way essentially
   | relies on the detection of a system property, either matching a particular value for the property,
   | or merely testing its existence. Profiles can also be activated by JDK version prefix, where a 
   | value of '1.4' might activate a profile when the build is executed on a JDK version of '1.4.2_07'.
   | Finally, the list of active profiles can be specified directly from the command line.
   |
   | NOTE: For profiles defined in the settings.xml, you are restricted to specifying only artifact
   |       repositories, plugin repositories, and free-form properties to be used as configuration
   |       variables for plugins in the POM.
   |
   |-->
  <profiles>
    <!-- profile
     | Specifies a set of introductions to the build process, to be activated using one or more of the
     | mechanisms described above. For inheritance purposes, and to activate profiles via <activatedProfiles/>
     | or the command line, profiles have to have an ID that is unique.
     |
     | An encouraged best practice for profile identification is to use a consistent naming convention
     | for profiles, such as 'env-dev', 'env-test', 'env-production', 'user-jdcasey', 'user-brett', etc.
     | This will make it more intuitive to understand what the set of introduced profiles is attempting
     | to accomplish, particularly when you only have a list of profile id's for debug.
     |
     | This profile example uses the JDK version to trigger activation, and provides a JDK-specific repo.
    <profile>
      <id>jdk-1.4</id>

      <activation>
        <jdk>1.4</jdk>
      </activation>

      <repositories>
        <repository>
          <id>jdk14</id>
          <name>Repository for JDK 1.4 builds</name>
          <url>http://www.myhost.com/maven/jdk14</url>
          <layout>default</layout>
          <snapshotPolicy>always</snapshotPolicy>
        </repository>
      </repositories>
    </profile>
    -->

    <!--
     | Here is another profile, activated by the system property 'target-env' with a value of 'dev',
     | which provides a specific path to the Tomcat instance. To use this, your plugin configuration
     | might hypothetically look like:
     |
     | ...
     | <plugin>
     |   <groupId>org.myco.myplugins</groupId>
     |   <artifactId>myplugin</artifactId>
     |   
     |   <configuration>
     |     <tomcatLocation>${tomcatPath}</tomcatLocation>
     |   </configuration>
     | </plugin>
     | ...
     |
     | NOTE: If you just wanted to inject this configuration whenever someone set 'target-env' to
     |       anything, you could just leave off the <value/> inside the activation-property.
     |
    <profile>
      <id>env-dev</id>

      <activation>
        <property>
          <name>target-env</name>
          <value>dev</value>
        </property>
      </activation>

      <properties>
        <tomcatPath>/path/to/tomcat/instance</tomcatPath>
      </properties>
    </profile>
    -->
  

<profile>

                <id>adobe-public</id>

                <activation>

                    <activeByDefault>true</activeByDefault>

                </activation>

                <repositories>

                  <repository>

                    <id>adobe</id>

                    <name>Nexus Proxy Repository</name>

                    <url>http://repo.adobe.com/nexus/content/groups/public/</url>

                    <layout>default</layout>

                  </repository>

                </repositories>

                <pluginRepositories>

                  <pluginRepository>

                    <id>adobe</id>

                    <name>Nexus Proxy Repository</name>

                    <url>http://repo.adobe.com/nexus/content/groups/public/</url>

                    <layout>default</layout>

                  </pluginRepository>

                </pluginRepositories>

            </profile>

</profiles>

  <!-- activeProfiles
   | List of profiles that are active for all builds.
   |
  <activeProfiles>
    <activeProfile>alwaysActiveProfile</activeProfile>
    <activeProfile>anotherAlwaysActiveProfile</activeProfile>
  </activeProfiles>
  -->
</settings>

Create an Experience Manager archetype project 

You can create an Experience Manager archetype project by using the Maven archetype plugin. In this example, assume that the working directory is C:\AdobeCQ. 

plugin1

To create an Experience Manager archetype project, perform these steps:

1. Open the command prompt and go to your working directory (for example, C:\AdobeCQ).

2. Run the following Maven command:

mvn archetype:generate -DarchetypeRepository=https://repo.adobe.com/nexus/content/groups/public/ -DarchetypeGroupId=com.day.jcr.vault -DarchetypeArtifactId=multimodule-content-package-archetype -DarchetypeVersion=1.0.2 -DgroupId=com.adobe.cq.sling.uploadcf -DartifactId=uploadcf -Dversion=1.0-SNAPSHOT -Dpackage=com.adobe.cq.sling.uploadcf -DappsFolderName=myproject -DartifactName="My Project" -DcqVersion="5.6.1" -DpackageGroup="My Company"

3. When prompted for additional information, specify Y.

4. Once done, you will see a message like:

[INFO] Finished at: Wed Mar 27 13:38:58 EDT 2013
[INFO] Final Memory: 10M/184M

5. Change the command prompt to the generated project. For example: C:\AdobeCQ\uploadcf. Run the following Maven command:
mvn eclipse:eclipse

After you run this command, you can import the project into Eclipse as discussed in the next section.

Add Java files to the Maven project using Eclipse

To make it easier to work with the Maven generated project, import it into the Eclipse development environment, as shown in the following illustration. 

Upload

 

The next step is to add a Java file to the com.adobe.cq.sling.uploadcf package named HandleFile. The Java class that you create in this section extends the Sling class named org.apache.sling.api.servlets.SlingAllMethodsServlet. This class supports the doPost method that lets you submit a file from the Java Swing client application. For information about this class, see Class SlingAllMethodsServlet.

The HandleFile class uses Apache Felix SCR annotations to create the OSGi component. For information about Apache Felix SCR annotations, see http://felix.apache.org/documentation/subprojects/apache-felix-maven-scr-plugin/scr-annotations.html.

A ResourceResolverFactory instance is injected into the doPost method. This instance creates a Session instance that lets you persist the file into the AEM JCR. To inject a ResourceResolverFactory instance, you use the @Reference annotation to define a class member, as shown in the following example.

//Inject a Sling ResourceResolverFactory
@Reference
private ResourceResolverFactory resolverFactory;

You invoke the ResourceResolver object's adaptTo method to create a Session object, as shown here.

//Persist the Data into the AEM JCR
//Invoke the adaptTo method to create a Session
ResourceResolver resourceResolver = resolverFactory.getAdministrativeResourceResolver(null);
session = resourceResolver.adaptTo(Session.class);

//Create a node that represents the root node
Node root = session.getRootNode();  

The Session object is used to retrieve JCR nodes and create new JCR nodes.   

Note:

When you open a JCR session, there is a reference to the JCR repository object. Every session will consume some memory unless the logout() method is called explicitly. If you do not call this call and create lots of sessions, you risk an out-of-memory exception by your JVM, which terminates the CQ instance. A single leaked session isn’t a problem, but if you have hundreds or thousands of leaked sessions, it might turn into a problem. For more information, see CQ development patterns – Sling ResourceResolver and JCR sessions

The HandleFile Java class also uses a SlingServlet annotation:

@SlingServlet(paths="/bin/upfile", methods = "POST", metatype=true)

The paths property corresponds to the URL that you specify when using Java HTTP application logic to post the file from the Java Swing application. The Sling Servlet created in this development article is configured so that authentication is not required by using a Property annotation.

@Property(name = "sling.auth.requirements", value = "-/bin/upfile")

Note:

Although this development shows you how to configure a Sling Servlet so that authentication is not required, it is strongly recommended that you use this only when required. There are some use cases for this. For example, when you need to create a Sling Servlet that collects data from anonymous users. In most use cases, it is strongly recommended that you code your Sling Servlets so that authentication is required. 

The following Java code represents the HandleFile class that extends org.apache.sling.api.servlets.SlingAllMethodsServlet.  This servlet persists the posted file into the AEM JCR that is specified by the Java Swing application.

package com.adobe.cq.sling.uploadcf;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.rmi.ServerException;
import java.util.Dictionary;
import java.util.Calendar;
import java.io.*;
 
import org.apache.felix.scr.annotations.Properties;
import org.apache.felix.scr.annotations.Property;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.sling.SlingServlet;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.SlingHttpServletResponse;
import org.apache.sling.api.servlets.SlingSafeMethodsServlet;
import org.apache.sling.commons.osgi.OsgiUtil;
import org.apache.sling.jcr.api.SlingRepository;
import org.apache.felix.scr.annotations.Reference;
import org.osgi.service.component.ComponentContext;
import javax.jcr.Session;
import javax.jcr.Node;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.fileupload.util.Streams;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Service;
import javax.jcr.ValueFactory;
import javax.jcr.Binary;
  
import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileOutputStream;
import java.util.Iterator;
import java.util.List;
import java.io.OutputStream;  
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
   
import java.io.StringWriter;
 
import java.util.ArrayList;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
   
import javax.jcr.Repository; 
import javax.jcr.SimpleCredentials; 
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
    
import org.apache.jackrabbit.commons.JcrUtils;
 
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
   
 
   
import javax.jcr.Session;
import javax.jcr.Node; 
 
//Sling Imports
import org.apache.sling.api.resource.ResourceResolverFactory ; 
import org.apache.sling.api.resource.ResourceResolver; 
import org.apache.sling.api.resource.Resource; 
 
//This is a component so it can provide or consume services
@SlingServlet(paths="/bin/upfile", methods = "POST", metatype=true)
@Property(name = "sling.auth.requirements", value = "-/bin/upfile")
public class HandleFile extends org.apache.sling.api.servlets.SlingAllMethodsServlet {
 private static final long serialVersionUID = 2598426539166789515L;
       
 private Session session;
 
 private String clientLibPath = ""; 
 
 /** Default log. */
 protected final Logger log = LoggerFactory.getLogger(this.getClass());
      
 //Inject a Sling ResourceResolverFactory
 @Reference
 private ResourceResolverFactory resolverFactory;
      
 @Override
 protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) throws ServerException, IOException {
        
         
     }
      
      
 @Override
 protected void doPost(SlingHttpServletRequest request, SlingHttpServletResponse response) throws ServerException, IOException {
        
      try
         {
         final boolean isMultipart = org.apache.commons.fileupload.servlet.ServletFileUpload.isMultipartContent(request);
         PrintWriter out = null;
         int index = 1 ; 
          
           out = response.getWriter();
           if (isMultipart) {
             final java.util.Map<String, org.apache.sling.api.request.RequestParameter[]> params = request.getRequestParameterMap();
             
             for (final java.util.Map.Entry<String, org.apache.sling.api.request.RequestParameter[]> pairs : params.entrySet()) {
               
            	 final String k = pairs.getKey();
               
                 final org.apache.sling.api.request.RequestParameter[] pArr = pairs.getValue();
               
                 final org.apache.sling.api.request.RequestParameter param0 = pArr[0];
                 
                 //Determine if the posted value is a file or the JCR Path
                 boolean formField = param0.isFormField(); //Is this a form field or a posted file
                 
                 if (formField)
                 {
                	 String libLoc = param0.getString();  
                	 clientLibPath = libLoc ; //Set the class member - its the first posted value from the client
                	 log.info("FIELD VALUE IS: "+libLoc )  ; 
                	 
                 }
                 else
                 {
                	 // final org.apache.sling.api.request.RequestParameter param1 = pArr[1];
                  final InputStream stream = param0.getInputStream();
                  String mimeType = param0.getContentType(); 
               
                  log.info("THE CONTENT TYPE IS: "+mimeType )  ; 
                  
                  //Save the uploaded file into the Adobe CQ DAM
                  writeToClientLib(stream,param0.getFileName(),clientLibPath,mimeType  ); 
                 }
                 index ++; 
             }
           }
         }
          
         catch (Exception e) {
             e.printStackTrace();
         }
      
     }
      
    
//Save the uploaded file into the specified client lib path
private String writeToClientLib(InputStream is, String fileName, String path, String mimetype)
{
try
{
    //Invoke the adaptTo method to create a Session
    ResourceResolver resourceResolver = resolverFactory.getAdministrativeResourceResolver(null);
    session = resourceResolver.adaptTo(Session.class);
     
    Node node = session.getNode(path);  //Get the client lib node in which to write the posted file
    javax.jcr.ValueFactory valueFactory = session.getValueFactory();             
    javax.jcr.Binary contentValue = valueFactory.createBinary(is);            
    Node fileNode = node.addNode(fileName, "nt:file"); 
    fileNode.addMixin("mix:referenceable"); 
    Node resNode = fileNode.addNode("jcr:content", "nt:resource"); 
    resNode.setProperty("jcr:mimeType", mimetype); 
    resNode.setProperty("jcr:data", contentValue); 
    Calendar lastModified = Calendar.getInstance(); 
    lastModified.setTimeInMillis(lastModified.getTimeInMillis()); 
    resNode.setProperty("jcr:lastModified", lastModified); 
    session.save();            
    session.logout();
      
    // Return the path to the document that was stored in CRX. 
    return fileNode.getPath();
}
catch(Exception e)
{
    e.printStackTrace();
}
return null; 
}
  
}

Modify the Maven POM file 

Modify the POM files to successfully build the OSGi bundle. In the POM file located at C:\AdobeCQ\uploadcf\bundle, add the following dependencies.

  • org.apache.felix.scr
  • org.apache.felix.scr.annotations
  • org.apache.jackrabbit
  • org.apache.sling

The following XML represents this POM file.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd ">
    <modelVersion>4.0.0</modelVersion>
    <!-- ====================================================================== -->
    <!-- P A R E N T P R O J E C T D E S C R I P T I O N -->
    <!-- ====================================================================== -->
    <parent>
        <groupId>com.adobe.cq.sling.uploadcf</groupId>
        <artifactId>uploadcf</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <!-- ====================================================================== -->
    <!-- P R O J E C T D E S C R I P T I O N -->
    <!-- ====================================================================== -->

    <artifactId>uploadcf-bundle</artifactId>
    <packaging>bundle</packaging>
    <name>adobe community Bundle</name>

    <!-- ====================================================================== -->
    <!-- B U I L D D E F I N I T I O N -->
    <!-- ====================================================================== -->
    <build>

        <plugins>
            <plugin>
                <groupId>org.apache.felix</groupId>
                <artifactId>maven-scr-plugin</artifactId>
                <executions>
                    <execution>
                        <id>generate-scr-descriptor</id>
                        <goals>
                            <goal>scr</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.felix</groupId>
                <artifactId>maven-bundle-plugin</artifactId>
                <extensions>true</extensions>
                <configuration>
                    <instructions>
                        <Bundle-SymbolicName>com.adobe.cq.sling.uploadcf.uploadcf-bundle</Bundle-SymbolicName>
                    </instructions>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.sling</groupId>
                <artifactId>maven-sling-plugin</artifactId>
                <configuration>
                    <slingUrl>http://${crx.host}:${crx.port}/apps/Upload/install</slingUrl>
                    <usePut>true</usePut>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
    </dependency>
     
    <dependency>
        <groupId>org.apache.sling</groupId>
        <artifactId>org.apache.sling.commons.osgi</artifactId>
        <version>2.2.0</version>
    </dependency>
     
    <dependency>
        <groupId>org.apache.sling</groupId>
        <artifactId>org.apache.sling.jcr.api</artifactId>
        <version>2.0.4</version>
      </dependency>
   
     
    <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.2</version>
        </dependency>
         
        <dependency>
         <groupId>org.apache.felix</groupId>
      
         <artifactId>org.osgi.core</artifactId>
      
         <version>1.4.0</version>
      </dependency>
       
       
       
      <dependency>
            <groupId>org.apache.sling</groupId>
            <artifactId>org.apache.sling.api</artifactId>
            <version>2.2.4</version>
            <scope>provided</scope>
        </dependency>
       
              
    <dependency>
            <groupId>org.osgi</groupId>
            <artifactId>org.osgi.compendium</artifactId>
        </dependency>
        <dependency>
            <groupId>org.osgi</groupId>
            <artifactId>org.osgi.core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.felix</groupId>
            <artifactId>org.apache.felix.scr.annotations</artifactId>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
        </dependency>
         
          
        <dependency>
         <groupId>org.apache.felix</groupId>
   
         <artifactId>org.osgi.core</artifactId>
   
         <version>1.4.0</version>
      </dependency>
         
        
          
    <dependency>
    <groupId>org.apache.jackrabbit</groupId>
    <artifactId>jackrabbit-core</artifactId>
    <version>2.4.3</version>
    </dependency>
       
    <dependency>
    <groupId>org.apache.jackrabbit</groupId>
    <artifactId>jackrabbit-jcr-commons</artifactId>
    <version>2.4.3</version>
    </dependency>
   <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>
           
    <dependency>
            <groupId>org.apache.sling</groupId>
            <artifactId>org.apache.sling.api</artifactId>
            <version>2.2.4</version>
            <scope>provided</scope>
        </dependency>
         
      <dependency>
         <groupId>javax.jcr</groupId>
         <artifactId>jcr</artifactId>
         <version>2.0</version>
      </dependency>
       
       <dependency>
            <groupId>com.day.cq.wcm</groupId>
            <artifactId>cq-wcm-api</artifactId>
            <version>5.5.0</version>
            <scope>provided</scope>
        </dependency>
         
        <dependency>
            <groupId>com.day.cq</groupId>
            <artifactId>cq-commons</artifactId>
            <version>5.5.0</version>
            <scope>provided</scope>
        </dependency>
         <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
        </dependency>     
               
    </dependencies>
     
    <repositories>
        <repository>
            <id>adobe</id>
            <name>Adobe Public Repository</name>
            <url>http://repo.adobe.com/nexus/content/groups/public/</url>
            <layout>default</layout>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>adobe</id>
            <name>Adobe Public Repository</name>
            <url>http://repo.adobe.com/nexus/content/groups/public/</url>
            <layout>default</layout>
        </pluginRepository>
    </pluginRepositories>       
      
</project>

Build the OSGi bundle using Maven

To build the OSGi component by using Maven, perform these steps:

  1. Open the command prompt and go to the C:\AdobeCQ\uploadcf folder.
  2. Run the following maven command: mvn clean install.
  3. The OSGi component can be found in the following folder: C:\AdobeCQ\uploadcf\bundle\target. The file name of the OSGi component is uploadcf-bundle-1.0-SNAPSHOT.jar.

Deploy the bundle to Experience Manager

Once you deploy the OSGi bundle, you can post process data files from the Java client application to the Sling Servlet. After you deploy the OSGi bundle, you can see it in the Apache Felix Web Console.

osgi

Deploy the OSGi bundle that contains the Sling Servlet by performing these steps:

  1. Login to Apache Felix Web Console at http://server:port/system/console/bundles (default admin user = admin with password= admin).
  2. Click the Bundles tab, sort the bundle list by Id, and note the Id of the last bundle.
  3. Click the Install/Update button.
  4. Browse to the bundle JAR file you just built using Maven. (C:\AdobeCQ\uploadcf\bundle\target).
  5. Click Install.
  6. Click the Refresh Packages button.
  7. Check the bundle with the highest Id.
  8. Click Active.
  9. Your new bundle should now be listed with the status Active.
  10. If the status is not Active, check the CQ error.log for exceptions. 

Note:

After you deploy the OSGi bundle to AEM, you can use the Java Swing client application to post a file to the specified client libs folder.

See also

Congratulations, you have just created both a Java Swing application and an AEM sling servlet that places uploaded files into a client library folder by using an Adobe Maven Archetype project. Please refer to the AEM community page for other articles that discuss how to build AEM services/applications by using an Adobe Maven Archetype project.

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