f:selectOneMenu参数 [英] f:selectOneMenu with parameter
问题描述
我有一组(用户)组和一个表，其中显示了这些组(和用户).每个组表头都包含一个f:selectOneMenu，它可以设置一个组范围的值.对于本示例，将其设为int值(0、5、10、15、20)的列表.在事物的简短版本下面
I have a set of groups (of users) and a table where I display these groups (and users). Each groups table header includes a f:selectOneMenu which allows to set a group-wide value. For the sake of this example, let it be a list of int values (0, 5, 10, 15, 20). Below the short version of things
Pojos:
public class User {
private int id;
private String name;
// .. getter, setter, equals, hashCode
}
public class Group {
private int id;
private String name;
// .. getter, setter, equals, hashCode
}
Bean:
@ManagedBean(name = "oneSelectController")
@ViewScoped
public class OneSelectController implements Serializable {
private List<User> users;
private List<Group> groups;
private List<Integer> values;
private Map<Group, List<User>> usersToGroup;
private Map<Group, List<Integer>> valuesToGroup;
public OneSelectController() {
log.info("New " + this.getClass().getSimpleName() + " ...");
users = new ArrayList<>(4);
users.add(new User(1, "User 1"));
users.add(new User(2, "User 2"));
users.add(new User(3, "User 3"));
users.add(new User(4, "User 4"));
groups = new ArrayList<>(5);
groups.add(new Group(1, "Group 1"));
groups.add(new Group(2, "Group 2"));
groups.add(new Group(3, "Group 3"));
groups.add(new Group(4, "Group 4"));
groups.add(new Group(5, "Group 5"));
values = Arrays.asList(0, 5, 10, 15, 20);
usersToGroup = new HashMap<>();
valuesToGroup = new HashMap<>();
for (Group g : groups) {
usersToGroup.put(g, users);
valuesToGroup.put(g, values);
}
}
public List<Group> getGroups() {
return groups;
}
public List<User> getUsers() {
return users;
}
public Integer getValueByGroup(Group group) {
// return value for given group
}
public List<Integer> getValuesByGroup(Group group) {
// return list of possible values
}
}
XHTML:
<p:dataTable id="userTable"
var="user"
value="#{oneSelectController.users}">
<p:column>
<f:facet name="header">
<div>User</div>
</f:facet>
<div>
<h:outputText value="#{user.name}"/>
</div>
</p:column>
<p:columns id="groups" value="#{oneSelectController.groups}" var="group">
<f:facet name="header">
<div>#{group.name}</div>
<div>
<h:selectOneMenu value="#{oneSelectController.getValueByGroup(group)}">
<f:selectItems value="#{oneSelectController.getValuesByGroup(group)}" />
</h:selectOneMenu>
</div>
</f:facet>
</p:columns>
</p:dataTable>
如何为h:selectOneMenu设置有效的二传手?无论我做什么，我最终都会遇到例外.设置器(必须以某种方式)必须能够获取所选的值，但还必须包含有关针对哪个组进行选择的信息.
How do I set up a working setter for the h:selectOneMenu? Whatever I do, I end up with exceptions. The setter (somehow) must be capable to take the value selected, but also contain the information for which group the selection was made.
推荐答案
getValueByGroup视为吸气剂，因为您将其与参数一起使用.我认为这里最好的方法是使用Map，为Group类正确实现hashCode()和equals()方法:
getValueByGroup is not considered a getter by JSF, since you're using it with a parameter. I think your best here is to use a Map, properly implementing the hashCode() and equals() methods for Group class:
在您的bean中:
private Map<Group, Integer> selectedValueByGroup = new HashMap<>();
//Getter
在视图中:
<h:selectOneMenu value="#{oneSelectController.selectedValueByGroup[group]}">
<f:selectItems value="#{oneSelectController.getValuesByGroup(group)}" />
</h:selectOneMenu>
此外，与具体问题无关，正如@Kukeltje指出的那样，您也可以使用Map结构来管理按组显示的值:
Also, unrelated to the concrete question and as @Kukeltje points out, you could use a Map structure to manage the values to show by group as well:
在您的bean中:
private Map<Group, List<Integer>> valuesByGroup = new HashMap<>();
//Getter
在视图中:
<h:selectOneMenu value="#{oneSelectController.selectedValueByGroup[group]}">
<f:selectItems value="#{oneSelectController.valuesByGroup[group]}" />
</h:selectOneMenu>
如果订购顺序对您也很重要，则可以考虑使用LinkedHashMap而不是HashMap.
You might consider using a LinkedHashMap instead of a HashMap if the ordering is important to you too.
另请参见:
- How to set a Map value in h:inputText
- https://www.geeksforgeeks.org/internal-working-of-hashmap-java/
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