Need Help with my JSF-Project - ResultSet to List to DataTable/c:foreach

Question

Hello!
I am struggeling heavily with JSF and JSTL and JSPs...
I want to show a list of names from a database in my JSF-Document.
I have the following bean "Category":
package de.fh_offenburg.audiodb.webapp;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.jsp.jstl.sql.Result;
public class Category {
     String name = "";
     String creationDate = "";
     int id_kategorie = 0;
     ResultSet resultset;
     Result result;
     Connection con;
     String query = "";
     List result_list;
     Category() {
          result_list = new ArrayList();
          try{
               con = new ConnectDB().connect();
               Statement statement = con.createStatement();
               query = "SELECT * FROM Category WHERE isUKat = '0'";
               resultset = statement.executeQuery(query);
               while (resultset.next()) {
                 // Get the data from the row using the column index
                 String name = resultset.getString("name");
                 // create an object for each row (yes, it is hibernate biased) ;-)
                 Cat cat = new Cat();
                 cat.setName(name);
                 cat.setId_kategorie(id_kategorie);
                 // Add the object to the list
                 result_list.add(cat);
          } catch(Exception hcat){
               System.out.println("HCat-Problem: "+hcat.getMessage());
     public java.lang.String getCreationDate() {
          return creationDate;
     public void setCreationDate(java.lang.String creationDate) {
          this.creationDate = creationDate;
     public int getId_kategorie() {
          return id_kategorie;
     public void setId_kategorie(int id_kategorie) {
          this.id_kategorie = id_kategorie;
     public java.lang.String getName() {
          return name;
     public void setName(java.lang.String name) {
          this.name = name;
     public java.sql.ResultSet getResultset() {
          return resultset;
     public void setResult_cat(java.sql.ResultSet result_cat) {
          this.resultset = result_cat;
     public void setResult(Result result) {
          this.result = result;
     public Result getResult() {
          return result;
     public List getResult_list() {
          return result_list;
     public void setResult_list(ArrayList result_list) {
          this.result_list = result_list;
     }This Bean is registered in my faces-config.xml like this:
<managed-bean>
  <managed-bean-name>category</managed-bean-name>
  <managed-bean-class>de.fh_offenburg.audiodb.webapp.Category</managed-bean-class>
  <managed-bean-scope>application</managed-bean-scope>
  <managed-property>
   <property-name>creationDate</property-name>
   <property-class>java.lang.String</property-class>
   <value/>
  </managed-property>
  <managed-property>
   <property-name>id_kategorie</property-name>
   <property-class>int</property-class>
   <value/>
  </managed-property>
  <managed-property>
   <property-name>name</property-name>
   <property-class>java.lang.String</property-class>
   <value/>
  </managed-property>
  <managed-property id="result">
   <property-name>result</property-name>
   <property-class>javax.servlet.jsp.jstl.sql.Result</property-class>
   <value/>
  </managed-property>
  <managed-property id="resultset">
   <property-name>resultset</property-name>
   <property-class>java.sql.ResultSet</property-class>
   <value/>
  </managed-property>
  <managed-property id="result_list">
   <property-name>result_list</property-name>
   <property-class>java.util.List</property-class>
   <value/>
  </managed-property>
</managed-bean>Now I try to read the list of Cats out in my JSF:
                                                  <h:dataTable value="#{category.result_list}" var="result">
                                                       <h:column>
                                                                      <h:outputText value="#{result.name}" />
                                                       </h:column>
                                                  </h:dataTable>... but that doesnt work... I got an error:
javax.servlet.ServletException: Cannot get value for expression '#{category.result_list}'
     javax.faces.webapp.FacesServlet.service(FacesServlet.java:152)
     org.ajax4jsf.framework.ajax.xmlfilter.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:96)
     org.ajax4jsf.framework.ajax.xmlfilter.BaseFilter.doFilter(BaseFilter.java:220)
     org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:144)
root cause So what am I doing wrong?
I did try to do the same with an JSTL-Syntax (which would be better for me, because I want to layout with DIVs not with a Table...):
                                                  <c:forEach items="#{category.result_list}" var="result">
                                                       <div class="div_mini_kat"><c:out value="#{result.name}"/></div>
                                                  </c:forEach>But that doesnt work out neigther...
Could someone please tell me what I am doing wrong? I am trying this for days now and I am feeling like a bumble-bee in a glasshouse with one small open doorway which I dont see and thousands of m^2 to crash with...
Thanks to everyone who answers in advance!!!
Fuchur

Answer 1

Hello!
I am struggeling heavily with JSF and JSTL and JSPs...
I want to show a list of names from a database in my JSF-Document.
I have the following bean "Category":
package de.fh_offenburg.audiodb.webapp;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.jsp.jstl.sql.Result;
public class Category {
     String name = "";
     String creationDate = "";
     int id_kategorie = 0;
     ResultSet resultset;
     Result result;
     Connection con;
     String query = "";
     List result_list;
     Category() {
          result_list = new ArrayList();
          try{
               con = new ConnectDB().connect();
               Statement statement = con.createStatement();
               query = "SELECT * FROM Category WHERE isUKat = '0'";
               resultset = statement.executeQuery(query);
               while (resultset.next()) {
                 // Get the data from the row using the column index
                 String name = resultset.getString("name");
                 // create an object for each row (yes, it is hibernate biased) ;-)
                 Cat cat = new Cat();
                 cat.setName(name);
                 cat.setId_kategorie(id_kategorie);
                 // Add the object to the list
                 result_list.add(cat);
          } catch(Exception hcat){
               System.out.println("HCat-Problem: "+hcat.getMessage());
     public java.lang.String getCreationDate() {
          return creationDate;
     public void setCreationDate(java.lang.String creationDate) {
          this.creationDate = creationDate;
     public int getId_kategorie() {
          return id_kategorie;
     public void setId_kategorie(int id_kategorie) {
          this.id_kategorie = id_kategorie;
     public java.lang.String getName() {
          return name;
     public void setName(java.lang.String name) {
          this.name = name;
     public java.sql.ResultSet getResultset() {
          return resultset;
     public void setResult_cat(java.sql.ResultSet result_cat) {
          this.resultset = result_cat;
     public void setResult(Result result) {
          this.result = result;
     public Result getResult() {
          return result;
     public List getResult_list() {
          return result_list;
     public void setResult_list(ArrayList result_list) {
          this.result_list = result_list;
     }This Bean is registered in my faces-config.xml like this:
<managed-bean>
  <managed-bean-name>category</managed-bean-name>
  <managed-bean-class>de.fh_offenburg.audiodb.webapp.Category</managed-bean-class>
  <managed-bean-scope>application</managed-bean-scope>
  <managed-property>
   <property-name>creationDate</property-name>
   <property-class>java.lang.String</property-class>
   <value/>
  </managed-property>
  <managed-property>
   <property-name>id_kategorie</property-name>
   <property-class>int</property-class>
   <value/>
  </managed-property>
  <managed-property>
   <property-name>name</property-name>
   <property-class>java.lang.String</property-class>
   <value/>
  </managed-property>
  <managed-property id="result">
   <property-name>result</property-name>
   <property-class>javax.servlet.jsp.jstl.sql.Result</property-class>
   <value/>
  </managed-property>
  <managed-property id="resultset">
   <property-name>resultset</property-name>
   <property-class>java.sql.ResultSet</property-class>
   <value/>
  </managed-property>
  <managed-property id="result_list">
   <property-name>result_list</property-name>
   <property-class>java.util.List</property-class>
   <value/>
  </managed-property>
</managed-bean>Now I try to read the list of Cats out in my JSF:
                                                  <h:dataTable value="#{category.result_list}" var="result">
                                                       <h:column>
                                                                      <h:outputText value="#{result.name}" />
                                                       </h:column>
                                                  </h:dataTable>... but that doesnt work... I got an error:
javax.servlet.ServletException: Cannot get value for expression '#{category.result_list}'
     javax.faces.webapp.FacesServlet.service(FacesServlet.java:152)
     org.ajax4jsf.framework.ajax.xmlfilter.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:96)
     org.ajax4jsf.framework.ajax.xmlfilter.BaseFilter.doFilter(BaseFilter.java:220)
     org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:144)
root cause So what am I doing wrong?
I did try to do the same with an JSTL-Syntax (which would be better for me, because I want to layout with DIVs not with a Table...):
                                                  <c:forEach items="#{category.result_list}" var="result">
                                                       <div class="div_mini_kat"><c:out value="#{result.name}"/></div>
                                                  </c:forEach>But that doesnt work out neigther...
Could someone please tell me what I am doing wrong? I am trying this for days now and I am feeling like a bumble-bee in a glasshouse with one small open doorway which I dont see and thousands of m^2 to crash with...
Thanks to everyone who answers in advance!!!
Fuchur