i'm trying to get a property value from a bean object inside jsp using standard actions,the initial html form go to a servlet which sets a value inside the desired property,sets the attribute inside the request object and then forwards it to the jsp page, the jsp gets the value from the property by using standard actions but it gets null!:
the bean object:
public class dog {
private String bread;
public String getBread() {
return bread;
}
public void setBread(String bread) {
this.bread = bread;
}
}
the servlet:
dog d=new dog();
d.setBread("Kizer");
request.setAttribute("bread", d);
RequestDispatcher view=request.getRequestDispatcher("index.jsp");
view.forward(request, response);
the JSP (index):
< id="person" class="com.example.model.dog" scope="request" />
Person created by servlet: <jsp:getProperty name="person" property="bread" />
why it returns null ?
In your JSP use
<jsp:useBean id="bread" class="com.example.model.dog" scope="request" />
<jsp:getProperty name="bread" property="bread" />
Using bean id atrribute is the same as bean object.
Related
I have in a servlet a property, I'm setting it's value in the servlet (with getters and setters).
Now, when I want to display the value on the jsf-page (xhtml), it has always the value 0. It's like it looses it'a state.
Servlet:
private int listSize;
private Method SomeMethod(some param){
...some code...
setListSize(int size);
...some code...
}
public int getListSize() {
return listSize;
}
public void setListSize(int size) {
this.listSize = size;
}
xhtml:
<h:outputText value="#{someServlet.listSize}" />
If you use servlet, you can put this value to HttpSession and in xhtml, you call:
<h:outputText value="#{session.getAttribute(yourAttribute)}"/>
Or you use controller, you write:
#ManagedBean
#ViewScoped
public class yourClassName
and in xhtml you call:
<h:outputText value="#{yourClassName.yourVariable}"/>
I have a .jsp form like so
<s:form action="AuditLogReport">Source IP<br>
<input type="text" class="auditLogSearch" name="sourceIp" value="All">
<input type="submit" value="Submit"/>
</s:form>
And my struts.xml is defined
<action name="AuditLogReport"
class="com.mycom.selfservice.actions.AuditLogAction" method="auditLogReport">
<result name="success">jsp/AuditLog.jsp</result>
<result name="error">jsp/Error.jsp</result>
</action>
Here is my class definition
public class AuditLogAction extends ActionSupport implements Action,ServletRequestAware {
And in my AuditLogAction class there is a method
public String auditLogReport() {
System.out.println("Im in auditLogReport...");
but when I click the button, auditLogReport method does not get hit. What I see in the browser url is http://localhost:7001/BPSelfServicePortal/AuditLogReport.action
It is appending .action which I think is why it doesn't find the method. So I tried putting
<constant name="struts.action.extension" value=""/>
in the struts.xml. That prevented the .action from being appended but the button still didn't work. Plus it caused the .css and images from being found. I have a link that uses the default execute() method and that works ok.
If I simply remove the .action in the url and hit enter, it hits the method but then none of the values in the form get passed.
Suggestions?
The problem turned out to be a Date parameter. Apparently struts2 doesn't like them.
public Date getFromDate() {
return fromDate;
}
public void setFromDate(Date fromDate) {
this.fromDate = fromDate;
}
Changed it to
public String getFromDate() {
return fromDate;
}
public void setFromDate(String fromDate) {
this.fromDate = fromDate;
}
And then it worked!
I have a (request-scoped) list from which the user may select a "PQ" (list of links). When clicked or otherwise entered into the browser the main page for each PQ shall be displayed. Each PQ's page is of the form
http://localhost:8080/projectname/main.jsf?id=2
Here's the PQ bean first:
#Named
#ViewScoped
public class PqHome implements Serializable
{
#PersistenceContext(unitName="...")
private EntityManager em;
private Integer id;
private PQ instance;
#PostConstruct
public void init()
{
System.out.println("ID is " + id); // ID from URL param
instance = em.find(PQ.class, id);
}
public Integer getId()
{
return id;
}
public void setId(Integer id)
{
this.id = id;
}
public PQ getInstance()
{
return instance;
}
}
Here's the main.xhtml:
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
...>
<ui:define name="metadata">
<f:metadata>
<f:viewParam name="id" value="#{pqHome.id}">
<f:convertNumber integerOnly="#{true}" />
</f:viewParam>
<!--f:event type="preRenderView" listener="#{pqHome.init}" /-->
</f:metadata>
</ui:define>
<ui:define name="title">
<h:outputText value="Main" />
</ui:define>
...
</ui:composition>
Any time I select or otherwise refresh the page/URL I get a NullPointerException from the EntityManager:
org.jboss.weld.exceptions.WeldException: WELD-000049 Unable to invoke [method] #PostConstruct public de.mycomp.myproj.beans.PqHome.init() on de.mycomp.myproj.beans.PqHome#4f0ea68f
at org.jboss.weld.bean.AbstractClassBean.defaultPostConstruct(AbstractClassBean.java:595)
...
Caused by: java.lang.IllegalArgumentException: id to load is required for loading
at org.hibernate.event.spi.LoadEvent.<init>(LoadEvent.java:87)
at org.hibernate.event.spi.LoadEvent.<init>(LoadEvent.java:59)
at org.hibernate.internal.SessionImpl.get(SessionImpl.java:961)
at org.hibernate.internal.SessionImpl.get(SessionImpl.java:957)
at org.hibernate.ejb.AbstractEntityManagerImpl.find(AbstractEntityManagerImpl.java:787)
at org.hibernate.ejb.AbstractEntityManagerImpl.find(AbstractEntityManagerImpl.java:762)
at org.jboss.as.jpa.container.AbstractEntityManager.find(AbstractEntityManager.java:221)
at de.mycomp.myproj.beans.PqHome.init(PqHome.java:47)
... 56 more
[Line 47 is em.find(...)]
The line
<f:event type="preRenderView" listener="#{pqHome.init}" />
doesn't make things any better. I'm pretty desparate now.
How do you get URL GET request params into an #ViewScoped bean?
Note: I bet it's not a trivial thing to do. Chances are I'm doing something wrong here conceptually, so any tips on how to improve are welcome. I felt that I needed to choose #ViewScoped because there will be more complex AJAX-based GUI on that page which I'd really like to keep accessible via URL GET params.
Thanks
There is a better way to get id from url. Just use it in #PostConstruct init() method to get "id" from url:
FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("id");
You can still use ViewScoped and #PostConstruct.
The #PostConstruct is invoked directly after bean's construction and all dependency injection (such as #PersistenceContext, #EJB, #ManagedProperty, #Inject, etc..etc..).
The <f:viewParam> sets its value during the update model values phase, which is far after (post)construction of the bean. So inside the #PostConstruct the <f:viewParam> value is simply not yet been set. It'll be still null at that point.
You're close with <f:event type="preRenderView">, but you have to remove the #PostConstruct annotation.
So:
<f:viewParam name="pq" value="#{pqHome.id}">
<f:convertNumber integerOnly="#{true}" />
</f:viewParam>
<f:event type="preRenderView" listener="#{pqHome.init}" />
with
private Integer id;
public void init() {
instance = em.find(PQ.class, id);
}
Unrelated to the concrete problem, I'd suggest to use a Converter for this instead. See also Communication in JSF 2.0 - Converting and validating GET request parameters.
Also the combination #Named #ViewScoped won't work as intended. The JSF-specific #ViewScoped works in combination with JSF-specific #ManagedBean only. Your CDI-specific #Named will behave like #RequestScoped this way. Either use #ManagedBean instead of #Named or use CDI-specific #ConversationScoped instead of #ViewScoped.
This question already has an answer here:
JSF does not populate #Named #RequestScoped bean with submitted input values
(1 answer)
Closed 5 years ago.
I have a bean with a field called 'name', and a JSF form that has an inputText mapped with this field. The initial value of the field is well displayed on the form.
The problem is when I submit the form, the value is not updated with the content of the inputText. In the savePlayer() method below, the value of name is always 'name', not what I typed inside the form input.
The bean :
#Named
#RequestScoped
public class PlayerForm {
#Inject
private PlayerRepository playerRepository;
private String name = "name";
public String savePlayer(){
Player player = new Player();
player.setName(name);
playerRepository.savePlayer(player);
return "saveUserOk";
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
}
The form :
<h:form>
<h:inputText value="#{playerForm.name}" />
<h:commandButton value="Submit" action="#{playerForm.savePlayer}" />
</h:form>
Thanks very much for any help!
This can happen if you imported #RequestScoped from the package javax.faces.bean (JSF) instead of from javax.enterprise.context (CDI). Every single EL expression #{} would then create a brand new and completely separate instance of the bean. The given form example would then end up in two instances of the bean, one where the name is set and another where the action is invoked.
The javax.faces.bean.RequestScoped annotation can only be used in conjunction with JSF's own #ManagedBean annotation not with CDI's #Named annotation.
I would like to know how to use jsp:setProperty in the following scenario. Here is a simple example of two java classes.
public class MyExample {
private MyName myNameExample = new MyName();
public MyExample() {}
public MyName getMyNameExample() {
return myNameExample;
}
public void setMyNameExample(MyName setTo) {
myNameExample = setTo;
}
}
public class MyName {
private String firstName;
public MyName() {}
public String getFirstName() {
return firstName;
}
public String setFirstName(String setTo) {
firstName = setTo;
}
}
I was trying to use something like:
<jsp:useBean id="example" class="MyExample" scope="page"/>
<jsp:setProperty name="example" property="????" value="aFirstName"/>
The important part here is that I want to reference the MyName object from within MyExample. Therefore, creating a bean to directly access MyName will not help me. So I am not looking for this answer:
<jsp:useBean id="name" class="MyName" scope="page"/>
<jsp:setProperty name="name" property="firstName" value="aFirstName"/>
You could just create both beans and set one in other by ${}.
<jsp:useBean id="myName" class="MyName" scope="page" />
<jsp:setProperty name="myName" property="firstName" value="aFirstName" />
<jsp:useBean id="myExample" class="MyExample" scope="page" />
<jsp:setProperty name="myExample" property="myExampleName" value="${myName}" />
Unrelated to the concrete problem, I'd suggest to invest time in learning servlets and MVC. The above is a pretty old fashioned and tight-coupled way of controlling the models in the view.
Note that using packageless classes may not work in all circumstances (since they are invisible for normal classes inside a package). Only in certain Apache Tomcat configurations it will work. Rather put your classes inside a package in order to be not dependent of that.