diff -r a7e543ab0c5f -r e2aa673dd473 src/main/java/de/uapcore/lightpit/modules/ProjectsModule.java
--- a/src/main/java/de/uapcore/lightpit/modules/ProjectsModule.java	Thu Oct 22 12:00:34 2020 +0200
+++ b/src/main/java/de/uapcore/lightpit/modules/ProjectsModule.java	Thu Oct 22 13:03:26 2020 +0200
@@ -74,42 +74,44 @@
             return;
 
         // Select Project
-        final int pid = Functions.parseIntOrZero(pathParameters.get("project"));
-        if (pid > 0) {
-            final var project = projectDao.find(pid);
-            if (project != null) {
-                final var info = new ProjectInfo(project);
-                info.setVersions(versionDao.list(project));
-                info.setComponents(componentDao.list(project));
-                info.setIssueSummary(projectDao.getIssueSummary(project));
-                viewModel.setProjectInfo(info);
-            }
-        }
+        final var project = projectDao.findByNode(pathParameters.get("project"));
+        if (project == null)
+            return;
+
+        final var info = new ProjectInfo(project);
+        info.setVersions(versionDao.list(project));
+        info.setComponents(componentDao.list(project));
+        info.setIssueSummary(projectDao.getIssueSummary(project));
+        viewModel.setProjectInfo(info);
 
         // Select Version
-        final var pathParamVersion = pathParameters.get("version");
-        if ("no-version".equals(pathParamVersion)) {
+        final var versionNode = pathParameters.get("version");
+        if ("no-version".equals(versionNode)) {
             viewModel.setVersionFilter(ProjectView.NO_VERSION);
-        } else if ("all-versions".equals(pathParamVersion)) {
+        } else if ("all-versions".equals(versionNode)) {
             viewModel.setVersionFilter(ProjectView.ALL_VERSIONS);
         } else {
-            final int vid = Functions.parseIntOrZero(pathParamVersion);
-            if (vid > 0) {
-                viewModel.setVersionFilter(versionDao.find(vid));
-            }
+            viewModel.setVersionFilter(versionDao.findByNode(project, versionNode));
         }
 
         // Select Component
-        final var pathParamComponent = pathParameters.get("component");
-        if ("no-component".equals(pathParamComponent)) {
+        final var componentNode = pathParameters.get("component");
+        if ("no-component".equals(componentNode)) {
             viewModel.setComponentFilter(ProjectView.NO_COMPONENT);
-        } else if ("all-components".equals(pathParamComponent)) {
+        } else if ("all-components".equals(componentNode)) {
             viewModel.setComponentFilter(ProjectView.ALL_COMPONENTS);
         } else {
-            final int cid = Functions.parseIntOrZero(pathParamComponent);
-            if (cid > 0) {
-                viewModel.setComponentFilter(componentDao.find(cid));
-            }
+            viewModel.setComponentFilter(componentDao.findByNode(project, componentNode));
+        }
+    }
+
+    private static String sanitizeNode(String node, String defaultValue) {
+        String result = node == null || node.isBlank() ? defaultValue : node;
+        result = result.replace('/', '-');
+        if (result.equals(".") || result.equals("..")) {
+            return "_"+result;
+        } else {
+            return result;
         }
     }
 
@@ -170,6 +172,10 @@
         try {
             final var project = new Project(getParameter(req, Integer.class, "pid").orElseThrow());
             project.setName(getParameter(req, String.class, "name").orElseThrow());
+
+            final var node = getParameter(req, String.class, "node").orElse(null);
+            project.setNode(sanitizeNode(node, project.getName()));
+
             getParameter(req, String.class, "description").ifPresent(project::setDescription);
             getParameter(req, String.class, "repoUrl").ifPresent(project::setRepoUrl);
             getParameter(req, Integer.class, "owner").map(
@@ -301,14 +307,23 @@
     public ResponseType commitVersion(HttpServletRequest req, HttpServletResponse resp, DataAccessObjects dao) throws IOException {
 
         try {
-            final var project = new Project(getParameter(req, Integer.class, "pid").orElseThrow());
+            final var project = dao.getProjectDao().find(getParameter(req, Integer.class, "pid").orElseThrow());
+            if (project == null) {
+                // TODO: improve error handling, because not found is not correct for this POST request
+                resp.sendError(HttpServletResponse.SC_NOT_FOUND);
+                return ResponseType.NONE;
+            }
             final var version = new Version(getParameter(req, Integer.class, "id").orElseThrow());
             version.setName(getParameter(req, String.class, "name").orElseThrow());
+
+            final var node = getParameter(req, String.class, "node").orElse(null);
+            version.setNode(sanitizeNode(node, version.getName()));
+
             getParameter(req, Integer.class, "ordinal").ifPresent(version::setOrdinal);
             version.setStatus(VersionStatus.valueOf(getParameter(req, String.class, "status").orElseThrow()));
             dao.getVersionDao().saveOrUpdate(version, project);
 
-            setRedirectLocation(req, "./projects/" + project.getId() + "/versions/");
+            setRedirectLocation(req, "./projects/" + project.getNode() + "/versions/");
             setContentPage(req, Constants.JSP_COMMIT_SUCCESSFUL);
         } catch (NoSuchElementException | IllegalArgumentException | SQLException ex) {
             resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED);
@@ -373,9 +388,18 @@
     public ResponseType commitComponent(HttpServletRequest req, HttpServletResponse resp, DataAccessObjects dao) throws IOException {
 
         try {
-            final var project = new Project(getParameter(req, Integer.class, "pid").orElseThrow());
+            final var project = dao.getProjectDao().find(getParameter(req, Integer.class, "pid").orElseThrow());
+            if (project == null) {
+                // TODO: improve error handling, because not found is not correct for this POST request
+                resp.sendError(HttpServletResponse.SC_NOT_FOUND);
+                return ResponseType.NONE;
+            }
             final var component = new Component(getParameter(req, Integer.class, "id").orElseThrow());
             component.setName(getParameter(req, String.class, "name").orElseThrow());
+
+            final var node = getParameter(req, String.class, "node").orElse(null);
+            component.setNode(sanitizeNode(node, component.getName()));
+
             component.setColor(getParameter(req, WebColor.class, "color").orElseThrow());
             getParameter(req, Integer.class, "ordinal").ifPresent(component::setOrdinal);
             getParameter(req, Integer.class, "lead").map(
@@ -385,7 +409,7 @@
 
             dao.getComponentDao().saveOrUpdate(component, project);
 
-            setRedirectLocation(req, "./projects/" + project.getId() + "/components/");
+            setRedirectLocation(req, "./projects/" + project.getNode() + "/components/");
             setContentPage(req, Constants.JSP_COMMIT_SUCCESSFUL);
         } catch (NoSuchElementException | IllegalArgumentException | SQLException ex) {
             resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED);
@@ -461,7 +485,13 @@
             } else {
                 component = null;
             }
-            issue.setProject(new Project(getParameter(req, Integer.class, "pid").orElseThrow()));
+            final var project = dao.getProjectDao().find(getParameter(req, Integer.class, "pid").orElseThrow());
+            if (project == null) {
+                // TODO: improve error handling, because not found is not correct for this POST request
+                resp.sendError(HttpServletResponse.SC_NOT_FOUND);
+                return ResponseType.NONE;
+            }
+            issue.setProject(project);
             getParameter(req, String.class, "category").map(IssueCategory::valueOf).ifPresent(issue::setCategory);
             getParameter(req, String.class, "status").map(IssueStatus::valueOf).ifPresent(issue::setStatus);
             issue.setSubject(getParameter(req, String.class, "subject").orElseThrow());
@@ -493,7 +523,7 @@
             dao.getIssueDao().saveOrUpdate(issue, issue.getProject());
 
             // TODO: fix issue #14
-            setRedirectLocation(req, "./projects/" + issue.getProject().getId() + "/all-components/all-versions/issues/");
+            setRedirectLocation(req, "./projects/" + issue.getProject().getNode() + "/all-components/all-versions/issues/");
             setContentPage(req, Constants.JSP_COMMIT_SUCCESSFUL);
 
             return ResponseType.HTML;
@@ -532,7 +562,7 @@
             dao.getIssueDao().saveComment(issueComment);
 
             // TODO: fix redirect location (e.g. after fixing #24)
-            setRedirectLocation(req, "./projects/" + issue.getProject().getId()+"/issues/"+issue.getId()+"/edit");
+            setRedirectLocation(req, "./projects/" + issue.getProject().getNode()+"/issues/"+issue.getId()+"/edit");
             setContentPage(req, Constants.JSP_COMMIT_SUCCESSFUL);
 
             return ResponseType.HTML;