Using java.util.Map in h:dataTable
I need to display Map
using <h:dataTable>
. My backing bean has a Map
property as below:
public class Bean {
private Map<Integer,String> map; // +getter
@PostConstruct
public void init() {
map = new TreeMap<Integer,String>();
map.put(1,"Sasi");
map.put(2,"Pushparaju");
map.put(3,"Venkat Raman");
map.put(3,"Prabhakaran");
}
}
Then in JSF page I am trying to bind this Map
property to the value
attribute of <h:dataTable>
.
<h:dataTable border="1" value="#{bean.map}" var="map">
<h:column id="column1">
<f:facet name="header">
<h:outputText value="UserId"></h:outputText>
</f:facet>
<h:outputText value="#{map.getKey}"></h:outputText>
</h:column>
<h:column id="column2">
<f:facet name="header">
<h:outputText value="Email Id"></h:outputText>
</f:facet>
<h:outputText value="#{map.getValue}"></h:outputText>
</h:column>
</h:dataTable>
It is giving en error that getKey
and getValue
is not present. I can understand that this is not the correct way to do it. How can I present a Map
using <h:dataTable>
?
Solution 1:
Until upcoming JSF 2.3, UIData
components such as <h:dataTable>
, <p:dataTable>
, etc and <ui:repeat>
does not support iterating over a Map
. This is only supported in <c:forEach>
.
One way is to convert the map entries to an array (alone entrySet()
won't work as UIData
also doesn't support Set
until upcoming JSF 2.3).
<h:dataTable value="#{bean.map.entrySet().toArray()}" var="entry">
<h:column>#{entry.key}</h:column>
<h:column>#{entry.value}</h:column>
</h:dataTable>
Another way is to wrap the map's entry set in a collection which the <h:dataTable>
can iterate over, such as an ArrayList
.
public class Bean {
private Map<Integer, String> map;
private List<Entry<Integer, String>> entries; // +getter (no setter necessary)
@PostConstruct
public void init() {
map = new TreeMap<>();
map.put(1, "Sasi");
map.put(2, "Pushparaju");
map.put(3, "Venkat Raman");
map.put(4, "Prabhakaran");
entries = new ArrayList<>(map.entrySet());
}
// ...
}
<h:dataTable value="#{bean.entries}" var="entry">
<h:column>#{entry.key}</h:column>
<h:column>#{entry.value}</h:column>
</h:dataTable>
However, more clean, self documenting and reusable is to use a List<User>
instead wherein the User
class has the necessary properties id
and name
.
public class Bean {
private List<User> users; // +getter (no setter necessary)
@PostConstruct
public void init() {
users = new ArrayList<>();
users.add(new User(1, "Sasi"));
users.add(new User(2, "Pushparaju"));
users.add(new User(3, "Venkat Raman"));
users.add(new User(4, "Prabhakaran"));
}
// ...
}
<h:dataTable value="#{bean.users}" var="user">
<h:column>#{user.id}</h:column>
<h:column>#{user.name}</h:column>
</h:dataTable>
Solution 2:
You can try this alternative too.
<h:dataTable border="1" value="#{myBean.map.keySet().toArray()}" var="myVar">
<h:column id="column1">
<f:facet name="header">
<h:outputText value="UserId"></h:outputText>
</f:facet>
<h:outputText value="#{myVar}"></h:outputText>
</h:column>
<h:column id="column2">
<f:facet name="header">
<h:outputText value="Email Id"></h:outputText>
</f:facet>
<h:outputText value="#{myBean.map.get(myVar)}"></h:outputText>
</h:column>
</h:dataTable>
Solution 3:
Regarding to the last answer from prageeth, you may use entrySet instead of keySet; then you can get rid of myBean.map.get. See this example:
<h:dataTable border="1" value="#{myBean.map.entrySet().toArray()}" var="map">
<h:column id="column1">
<f:facet name="header">
<h:outputText value="UserId"></h:outputText>
</f:facet>
<h:outputText value="#{map.key}"></h:outputText>
</h:column>
<h:column id="column2">
<f:facet name="header">
<h:outputText value="Email Id"></h:outputText>
</f:facet>
<h:outputText value="#{map.value}"></h:outputText>
</h:column>
</h:dataTable>
This works on myfaces 2.2.3 as I've just used it myself.
Annotation: I'd better had commented the last post, but my reputation is not high enough, therefore this is an extra answer.