Chapter 2. Securing management interfaces and applications

Procedure

1. Set up a Maven project using the mvn command. The command creates the directory structure for the project and the pom.xml configuration file.

   Syntax

   $ mvn archetype:generate \
   -DgroupId=${group-to-which-your-application-belongs} \
   -DartifactId=${name-of-your-application} \
   -DarchetypeGroupId=org.apache.maven.archetypes \
   -DarchetypeArtifactId=maven-archetype-webapp \
   -DinteractiveMode=false

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   Example

   $ mvn archetype:generate \
   -DgroupId=com.example.app \
   -DartifactId=simple-webapp-example \
   -DarchetypeGroupId=org.apache.maven.archetypes \
   -DarchetypeArtifactId=maven-archetype-webapp \
   -DinteractiveMode=false

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2. Navigate to the application root directory:

   Syntax

   $ cd <name-of-your-application>

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   Example

   $ cd simple-webapp-example

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3. Replace the content of the generated pom.xml file with the following text:

   <?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/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
   
     <groupId>com.example.app</groupId>
     <artifactId>simple-webapp-example</artifactId>
     <version>1.0-SNAPSHOT</version>
     <packaging>war</packaging>
   
     <name>simple-webapp-example Maven Webapp</name>
     <!-- FIXME change it to the project's website -->
     <url>http://www.example.com</url>
   
       <properties>
           <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
           <maven.compiler.source>11</maven.compiler.source>
           <maven.compiler.target>11</maven.compiler.target>
           <version.maven.war.plugin>3.4.0</version.maven.war.plugin>
       </properties>
   
       <dependencies>
           <dependency>
               <groupId>jakarta.servlet</groupId>
               <artifactId>jakarta.servlet-api</artifactId>
               <version>6.0.0</version>
               <scope>provided</scope>
           </dependency>
       </dependencies>
   
       <build>
           <finalName>${project.artifactId}</finalName>
           <plugins>
               <plugin>
                   <groupId>org.apache.maven.plugins</groupId>
                   <artifactId>maven-war-plugin</artifactId>
                   <version>${version.maven.war.plugin}</version>
               </plugin>
               <plugin>
                   <groupId>org.wildfly.plugins</groupId>
                   <artifactId>wildfly-maven-plugin</artifactId>
                   <version>4.2.2.Final</version>
               </plugin>
           </plugins>
       </build>
   </project>

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Procedure

1. Create a directory to store the Java files.

   Syntax

   $ mkdir -p src/main/java/<path_based_on_artifactID>

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   Example

   $ mkdir -p src/main/java/com/example/app

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2. Navigate to the new directory.

   Syntax

   $ cd src/main/java/<path_based_on_artifactID>

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   Example

   $ cd src/main/java/com/example/app

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3. Create a file SecuredServlet.java with the following content:

   package com.example.app;
   
   import java.io.IOException;
   import java.io.PrintWriter;
   import java.security.Principal;
   
   import jakarta.servlet.ServletException;
   import jakarta.servlet.annotation.WebServlet;
   import jakarta.servlet.http.HttpServlet;
   import jakarta.servlet.http.HttpServletRequest;
   import jakarta.servlet.http.HttpServletResponse;
   
   /**
    * A simple secured HTTP servlet. It returns the user name of obtained
    * from the logged-in user's Principal. If there is no logged-in user,
    * it returns the text "NO AUTHENTICATED USER".
    */
   
   @WebServlet("/secured")
   public class SecuredServlet extends HttpServlet {
   
       @Override
       protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
           try (PrintWriter writer = resp.getWriter()) {
               writer.println("<html>");
               writer.println("  <head><title>Secured Servlet</title></head>");
               writer.println("  <body>");
               writer.println("    <h1>Secured Servlet</h1>");
               writer.println("    <p>");
               writer.print(" Current Principal '");
               Principal user = req.getUserPrincipal();
               writer.print(user != null ? user.getName() : "NO AUTHENTICATED USER");
               writer.print("'");
               writer.println("    </p>");
               writer.println("  </body>");
               writer.println("</html>");
           }
       }
   
   }

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4. In the application root directory, compile your application with the following command:

   $ mvn package
   ...
   [INFO] ------------------------------------------------------------------------
   [INFO] BUILD SUCCESS
   [INFO] ------------------------------------------------------------------------
   [INFO] Total time: 1.015 s
   [INFO] Finished at: 2022-04-28T17:48:53+05:30
   [INFO] ------------------------------------------------------------------------

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5. Deploy the application.

   $ mvn wildfly:deploy

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