nothing is working!!!

pom.xml

@@ -174,6 +174,13 @@
             <version>5.4.0</version>
             <scope>test</scope>
         </dependency>
+
+        <!-- other -->
+        <dependency>
+            <groupId>javaee</groupId>
+            <artifactId>javaee-api</artifactId>
+            <version>5</version>
+        </dependency>
     </dependencies>
 
 

src/main/java/de/hsel/itech/jsf/CartBean.java

@@ -1,6 +1,7 @@
 package de.hsel.itech.jsf;
 
 import de.hsel.itech.db.Database;
+import de.hsel.itech.db.pojo.Book;
 import de.hsel.itech.db.pojo.ShoppingCartItem;
 import de.hsel.itech.db.pojo.User;
 import lombok.Getter;
@@ -9,6 +10,7 @@ import lombok.Setter;
 import javax.faces.annotation.ManagedProperty;
 import javax.faces.bean.ManagedBean;
 import javax.faces.bean.RequestScoped;
+import javax.faces.context.FacesContext;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -16,11 +18,30 @@ import java.util.List;
 @RequestScoped
 public class CartBean {
 
-    @Getter
     @Setter
     @ManagedProperty("#{userBean.user}")
     private User user;
 
+    @Setter
+    @Getter
+    private long isbn;
+
+    public User getUser() {
+        FacesContext context = FacesContext.getCurrentInstance();
+        return (User) context.getApplication().evaluateExpressionGet(context,"#{userBean.user}", User.class);
+    }
+
+    public String add(){
+        System.out.println("isbn: " + isbn);
+        if(Database.getInstance().book().exists(isbn)){
+            Book book = Database.getInstance().book().get(isbn);
+            Database.getInstance().shoppingCart().insert(new ShoppingCartItem(user,book,1));
+        }else{
+            return "index.jsf";
+        }
+        return "cart.jsf";
+    }
+
     public List<ShoppingCartItem> getItems(){
         Database db = Database.getInstance();
         if(user==null){

src/main/webapp/bookinfo.xhtml

@@ -13,6 +13,12 @@
 
             <h:form>
                 <h:commandLink action="#{bookBean.back}" value="zurück zur Auswahl" rendered="#{not empty bookBean}"/>
+                <br/>
+                <h:commandLink action="#{cartBean.add}">
+                    <f:setPropertyActionListener target="#{cartBean.isbn}" value="#{bookBean.book.isbn}"/>
+                    <i class="fas fa-cart-plus"/>
+                    in den Warenkorb
+                </h:commandLink>
             </h:form>
 
             <h:panelGroup layout="block" rendered="#{empty bookBean.book}">
@@ -49,10 +55,14 @@
                         <br/>
                         <br/>
                         <div class="m-button m-success">
-                            <a href="#">
+                            <h:form>
+                                <h:commandLink action="#{cartBean.add}">
+                                    <f:setPropertyActionListener target="#{cartBean.isbn}"
+                                                                 value="#{bookBean.book.isbn}"/>
                                     <i class="fas fa-cart-plus"/>
                                     in den Warenkorb
-                            </a>
+                                </h:commandLink>
+                            </h:form>
                         </div>
                     </div>
                 </div>

src/main/webapp/cart.xhtml

@@ -9,20 +9,20 @@
     <ui:composition template="template.xhtml">
         <ui:define name="content">
 
+            #{cartBean.isbn}
+
             <ui:repeat value="#{cartBean.items}" var="item">
                 <li>
                     <h:outputLabel value="#{item.article.title}"/>
                 </li>
             </ui:repeat>
 
-            #{userBean.user.name}
-            #{cartBean.user.name}
-
             <div class="m-row">
                 <div class="m-col-t-3 m-push-t-5 m-button m-success">
                     <a href="#">Jetzt Kaufen</a>
                 </div>
             </div>
+
         </ui:define>
     </ui:composition>
 </f:view>