added app code

pom.xml

@@ -0,0 +1,88 @@
+<?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>de.svedie</groupId>
+  <artifactId>mayan_edms_export</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+  <name>Mayan EDMS Dokument Exporter</name>
+  <url>http://svedie.de</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.postgresql</groupId>
+      <artifactId>postgresql</artifactId>
+      <version>42.3.3</version>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
+      <plugins>
+        <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
+        <plugin>
+          <artifactId>maven-clean-plugin</artifactId>
+          <version>3.1.0</version>
+        </plugin>
+        <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
+        <plugin>
+          <artifactId>maven-resources-plugin</artifactId>
+          <version>3.0.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-compiler-plugin</artifactId>
+          <version>3.8.0</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-surefire-plugin</artifactId>
+          <version>2.22.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-jar-plugin</artifactId>
+          <version>3.0.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-install-plugin</artifactId>
+          <version>2.5.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-deploy-plugin</artifactId>
+          <version>2.8.2</version>
+        </plugin>
+        <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
+        <plugin>
+          <artifactId>maven-site-plugin</artifactId>
+          <version>3.7.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-project-info-reports-plugin</artifactId>
+          <version>3.0.0</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-assembly-plugin</artifactId>
+          <configuration>
+            <finalName>Mayan EDMS Exporter</finalName>
+            <appendAssemblyId>false</appendAssemblyId>
+            <archive>
+              <manifest>
+                <mainClass>de.svedie.mayan_edms_export.App</mainClass>
+              </manifest>
+            </archive>
+            <descriptorRefs>
+              <descriptorRef>jar-with-dependencies</descriptorRef>
+            </descriptorRefs>
+          </configuration>
+        </plugin>
+      </plugins>
+    </pluginManagement>
+  </build>
+</project>

src/main/java/de/svedie/mayan_edms_export/App.java

@@ -0,0 +1,79 @@
+package de.svedie.mayan_edms_export;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Exports the Mayan EDMS files.
+ */
+public class App {
+
+    public static void main(String[] args) throws SQLException, IOException {
+
+        if (args.length < 5) {
+            System.out.println(
+                    "please enter the parameters \n1. database ip and database (example:192.168.0.2/mayan) \n2. database user \n3. database password \n4. mayan document directory \n5. export directory");
+            System.exit(0);
+        }
+
+        System.out.println("programm started ...");
+
+        System.out.println("connecting to the database ...");
+        String url = "jdbc:postgresql://" + args[0] + "?user=" + args[1] +
+                "&password=" + args[2];
+        Connection connection = DriverManager.getConnection(url);
+
+        System.out.println("connection successfull ...");
+
+        System.out.println("querying database table documents_documentfile ...");
+        Statement statement = connection.createStatement();
+        ResultSet query = statement
+                .executeQuery("select file, document_id, filename from documents_documentfile order by document_id");
+
+        List<Triple<String, Integer, String>> files = new ArrayList<>();
+        while (query.next()) {
+            String file = query.getString("file");
+            int id = query.getInt("document_id");
+            String filename = query.getString("filename");
+
+            String absolutePath = Paths.get(args[3] + file).toFile().getAbsolutePath();
+
+            Triple<String, Integer, String> filetriple = new Triple<>(absolutePath, id,
+                    filename);
+            files.add(filetriple);
+        }
+
+        if (files.size() > 0) {
+            System.out.println(files.size() + " records in the database found ...");
+        }
+
+        System.out.println("starting copy process ...");
+        for (Triple<String, Integer, String> file : files) {
+            Path newdir = Path.of(args[4]);
+            try {
+                Files.copy(Path.of(file.getFile()), newdir.resolve(file.getFilename()));
+            } catch (Exception e) {
+                System.out.println("duplicate file: " + file.getFile() + " -#- filename: " +
+                        file.getFilename());
+            }
+        }
+
+        System.out.println("copy process finished ...");
+
+        try {
+            System.out.println("closing the database connection ...");
+            connection.close();
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+    }
+}

src/main/java/de/svedie/mayan_edms_export/Triple.java

@@ -0,0 +1,29 @@
+package de.svedie.mayan_edms_export;
+
+/**
+ * Holds the information about the files.
+ */
+public class Triple<F, I, N> {
+
+    private final String file;
+    private final Integer id;
+    private final String filename;
+
+    public Triple(String file, Integer id, String filename) {
+        this.file = file;
+        this.id = id;
+        this.filename = filename;
+    }
+
+    public String getFile() {
+        return file;
+    }
+
+    public Integer getId() {
+        return id;
+    }
+
+    public String getFilename() {
+        return filename;
+    }
+}